Laurie Reisberg

@article{Pin_etal2022,

title = {Thermodynamic modeling of melt addition to peridotite: Implications for the refertilization of the non-cratonic continental mantle lithosphere},

author = {J. Pin and L. France and S. Lambart and L. Reisberg},

doi = {10.1016/j.chemgeo.2022.121050},

year  = {2022},

date = {2022-01-01},

journal = {Chemical Geology},

volume = {609},

pages = {121050},

abstract = {In a classic model of evolution of the non-cratonic continental mantle lithosphere, harzburgites represent the refractory (\<5% clinopyroxene) residues of high degrees of partial melting of fertile mantle, while lherzolites (\>5% clinopyroxene) represent residues of lesser degrees of partial melting. However, partial melting is not the only process that could explain the peridotite compositional variability that ranges from fertile (\>2 wt% Al2O3, \<45 wt% MgO) to refractory (\<2 wt% Al2O3, \>45 wt% MgO). In the refertilization process, harzburgite is a refractory protolith (potentially previously formed by partial melting of a fertile mantle) that undergoes reactive percolation of silicate melts derived from the underlying asthenosphere, resulting in the crystallization of a new generation of minerals (mostly clinopyroxene). A simple but critical first step towards understanding therefertilization process is to examine how modal and major element compositions evolve as melts are added to peridotites. Here we use a thermodynamically-constrained two-component mixing model to independently evaluate the roles of five different parameters: pressure, temperature, redox conditions, and compositions of the initial peridotite and the added basaltic melt (hereafter referred to P-T-fO2-X$pi$-Xmelt), during melt addition. We compare the results with observed suites of peridotites. The main observations are as follows: (1) the produced model is consistent with the global peridotite database, and (2) T, fO2 and small variations of pressure have almost no impact on the evolution of the system. In contrast, the mineralogy of the percolated harzburgite has a substantial effect on the variation of the modal proportions. The parameter with the most significant impact is Xmelt, which is directly linked to the geodynamic context and melting conditions. This parameter directly controls the refertilization reaction and so, the phase proportions and the bulk-rock composition. Elements that partition preferentially in the melt phase (e.g., Na) display depletions in natural assemblages that are stronger than those predicted from the simple mixing model, consistent with the fact that the natural process occurs in an open system, and that reactive percolation likely results in incompatible element enrichment in the associated melt. Our results corroborate the suggestion that most of the spectrum of compositional variability observed in lithospheric mantle peridotites can be explained by the impregnation of primitive silicate melt in refractory harzburgites.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jegal_etal2022,

title = {Characterisation of reference materials for In situ Rb-Sr dating by LA-ICP-MS/MS},

author = {Y. Jegal and C. Zimmermann and L. Reisberg and D. Yeghicheyan and C. Cloquet and C. Peiffert and M. Gerardin and E. Deloule and J. Mercadier},

doi = {10.1111/ggr.12456},

year  = {2022},

date = {2022-01-01},

journal = {Geostandards and Geoanalytical Research},

volume = {46},

number = {4},

pages = {645--671},

abstract = {We present Rb and Sr mass fraction and 87Sr/86Sr isotope ratio measurement results for four reference materials (RMs) obtained from the Service d’Analyse des Roches et des Min\'{e}raux (SARM), Nancy, France: Mica-Mg, Mica-Fe, GL-O and FK-N. These four RMs have different chemical compositions spanning the range of those of most K-bearing feldspars and micas, making them potential calibration materials for in situ Rb-Sr dating of natural minerals by LA-ICP-MS/MS. Selected grains and flakes from the four RMs present variable degrees of heterogeneity observable by SEM-EDS and EPMA imaging, and chemical mapping. This heterogeneity is mainly related to inclusions of minerals within flakes and grains and to chemical substitutions linked to crystallographic control and alteration processes. The Mica-Mg RM is the least affected. The powders available at the SARM were analysed by ID-TIMS (87Sr/86Sr and Sr) and ID-MC-ICP-MS (Rb) after digestion and separation. The mean 87Rb/86Sr ratios are 155.6thinspacetextpmthinspace4.7% (2s, as for other RMs) for Mica-Mg, 1815thinspacetextpmthinspace14% for Mica-Fe, 36.2thinspacetextpmthinspace11% for GL-O and 69.9thinspacetextpmthinspace5.9% for FK-N. The mean 87Sr/86Sr ratios are 1.8622thinspacetextpmthinspace0.36% (2s, as for other RMs) for Mica-Mg, 7.99thinspacetextpmthinspace13% for Mica-Fe, 0.75305thinspacetextpmthinspace0.12% for GL-O, and 1.2114thinspacetextpmthinspace0.17% for FK-N. The four RMs each show dispersion in 87Sr/86Sr and Rb and Sr mass fractions, to degrees that differ between RMs and that reflect the heterogeneity of their original crystals. The most heterogeneous RMs are GL-O and Mica-Fe. The calculated mean Rb-Sr isotopic ages are 521thinspacetextpmthinspace24 Ma for Mica-Mg, 287thinspacetextpmthinspace55 Ma for Mica-Fe, 89.2thinspacetextpmthinspace9.9 Ma for GL-O and 512thinspacetextpmthinspace30 Ma for FK-N. The proposed age for Mica-Fe may be unreliable due to the elevated dispersion of individual analysis linked to the highly radiogenic composition of the biotite and to the presence of numerous mineral inclusions. We recommend use of these proposed working values of 87Sr/86Sr and 87Rb/86Sr ratios and associated uncertainties when using the four RMs for in situ Rb-Sr dating by LA-ICP-MS/MS. The availability of these four well-characterised RMs will allow progress in the development and application of the Rb-Sr dating approach by LA-ICP-MS/MS.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Banerjee_etal2022,

title = {Fractionation of trace and platinum-group elements during metamorphism of komatiitic chromites from the early Archean Gorumahishani greenstone belt, Singhbhum Craton (eastern India)},

author = {R. Banerjee and S. K. Mondal and L. Reisberg and J. W. Park},

doi = {10.1007/s00410-022-01943-4},

year  = {2022},

date = {2022-01-01},

journal = {Contributions to Mineralogy and Petrology},

volume = {177},

number = {75},

abstract = {It is well established that the major and minor element contents of chromites are subject to change during greenschist to amphibolite facies metamorphism. During upper amphibolite facies metamorphism, chromite can be completely converted to chrome magnetite. However, not all elements are affected to the same degree, the concentrations of +2 ions (e.g. Zn, Co, Mn) being particularly vulnerable to modification. The degree to which trace elements, particularly the platinum-group elements (PGE), are affected has not been closely examined. The compositions and textures of chromites from komatiites of the Gorumahishani greenstone belt of the Singhbhum Craton (India) have experienced a range of metamorphic conditions from greenschist to amphibolite facies, providing the opportunity to study the changes of trace and platinum-group element composition with metamorphic grade. Five types of altered chromites are identified from the komatiitic suite of rocks in thethinspacetextasciitilde120-km-long greenstone belt. The type-I chromites are non-porous and characterized by the least modified cores. These chromites are mostly present in the northern Maharajgunj-Tua Dungri section where rocks show metamorphism from greenschist to greenschist-amphibolite transition facies. The type-II and type-III chromites are porous and mostly found in the southern Kapili section of the greenstone belt where rocks show metamorphism up to the mid-amphibolite facies. Type-IV and type-V chromites are completely modified to ferritchromit and chrome magnetite, respectively, and are present in the komatiitic rocks from the entire greenstone belt. The central cores of the type-I and type-II grains have relatively higher concentrations of mobile trace elements (e.g. Zn, Co, and Mn) with higher Mg# [Mg/(Mgthinspace+thinspaceFe2+)], lower Cr# [Cr/(Crthinspace+thinspaceAl)], and lower Fe3+/R3+ (R3+thinspace=thinspaceFe3+thinspace+thinspaceCr3+thinspace+thinspaceAl3+) ratios than their respective rims. Significantly higher concentrations of the immobile trace elements (e.g. Ti and V) in the cores of the type-II grains relative to their chrome magnetite rims from the Kapili section and to the type-I varieties from other sections might be due to the metamorphism of the komatiitic rocks under higher-grade conditions (amphibolite facies). In situ LA-ICPMS analysis for PGE reveals a relatively higher concentration of Ru and Rh in the rims of the type-I chromites than in the cores which is due to the diffusion of these elements from the normal spinel structure of the cores towards the bivalent octahedral sites of the inverse spinel structure of the chrome magnetite rims during metamorphic processes. The lower concentrations of Os, Ir, Ru, and Rh in the cores of the type-II chromites from the Kapili section might be related to the metamorphism of the rocks under higher-grade conditions that facilitated the diffusion of these elements to associated sulphide or platinum-group mineral or alloy phases. The calculated partition coefficients of Sc, Ti, V, Mn, Ni, Ga, Os, Ir, Ru, and Rh from the least altered chromite cores assuming equilibrium with the parental komatiitic melt also suggest the variable effects of metamorphism when compared with global experimental and empirical values of the natural samples.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Combes_etal2022,

title = {Integrated geological-geophysical investigation of gold-hosting Rhyacian intrusions (Yaou, French Guiana), from deposit-to district-scale},

author = {M. Combes and A. Eglinger and A. S. Andre-Mayer and Y. teitler and M. Jessell and A. Zeh and L. Reisberg and A. Heuret and P. Gilbert},

doi = {10.1016/j.jsames.2021.103708},

year  = {2022},

date = {2022-01-01},

journal = {Journal of South American Earth Sciences},

volume = {114},

pages = {103708},

abstract = {The mineral system concept, which combines integrated information from all kinds of geological and geophysical studies, is a very useful approach to predict and locate structures and lithologies potentially associated with gold mineralization at all scales (i.e., upscaling from craton-to district-to camp-to deposit-scale). This is demonstrated in this study where the Yaou deposit, located in French Guiana within Rhyacian terranes, formed and deformed during the Trans-Amazonian orogenic cycle (ca. 2600-1950 Ma), is used as a case study. The deposit comprises numerous intrusions hosting the bulk of the high-grade gold mineralization at Yaou, associated with a quartz-carbonate veining system. Both intrusive and gold events are dated in order to constrain Yaou in the regional litho-structural framework. Spatially associated with the Central Yaou Shear Zone (CYSZ), one of the quartz monzodiorite yields a U--Pb zircon age of 2131 textpm 6 Ma, supra-chondritic $epsilon$Hft of ca. 2.5, and Hf model ages at ca. 2.6--2.4 Ga. These data suggest Paleoproterozoic rock formation due to reworking of juvenile crust, derived from the depleted mantle during the late Archean to early Paleoproterozoic. The main and economic gold event hosted by the quartz monzodiorite is dated at 2105 textpm 25 Ma by Re--Os isotope analyses of Au-bearing pyrite, representing the first date for gold mineralization in French Guiana. A multi-scale approach using airborne magnetic and radiometric data allows to better understand the spatial distribution of the intrusions and possibly associated shear zones, both related to gold mineralization events. The intrusions and associated shear zones are interpreted as being parallel along a N60textdegree trend and replicated laterally toward the northwest. A temporal association is defined between the shearing deformation and the magmatic event, both being synchronous with a possibility of pre-shearing intrusion and a protracted magmatic phase active while shearing. The Yaou-type intrusion-hosted mineralization can be targeted along these N60textdegree-striking structures. This integrated approach opens some targeting options, previously unrecognized within the southern Paramaca Greenstone Belt.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mamadou_etal2022,

title = {The Tim Merso"i Basin uranium deposits (Northern Niger): Geochronology and genetic model},

author = {M. M. Mamadou and M. Cathelineau and E. Deloule and L. Reisberg},

doi = {10.1016/j.oregeorev.2022.104905},

year  = {2022},

date = {2022-01-01},

journal = {Ore Geology Reviews},

volume = {145},

pages = {104905},

abstract = {The Tim Merso"i uranium province in northern Niger is one of the world’s largest uranium reserves and fourthhighest uranium producer. The main uranium deposits (Arlit, Akouta, and Imouraren) are located in continental siliciclastic formations. The regional north--south-trending fault (the Arlit Fault) strongly controls them, as well as secondary discontinuity networks oriented NNE-SSW, ENE-WSW, and WNW-ESE. The Arlit and Akouta uranium-ores are hosted in reduced Carboniferous formations and occur as reduced U4+ phase mineralizations.Besides, the Imouraren deposit is hosted by an oxidized Jurassic formation with a predominance of U6+ silicate and vanadate minerals and relics of reduced mineralization. New U-Pb SIMS data have been obtained on the three deposits, and the results reveal two main stages of uranium deposition and ore metallogenesis. (i) the 90--145 Ma Lower Cretaceous mineralization is related to a significant tectonothermal event, synchronous with the Atlantic rifting that induced the deformation and brine migration from Triassic formations. Primary uraninite and chalcocite are formed by fluid mixing in a reduced environment at that stage at a depth of 1 km at less at a temperature 115--150 ◦C, hotter than that of the reservoir. (ii) During later Cenozoic exhumation of the basin, a series of remobilizations of primary uranium stock resulted in the formation of much younger uraninites under reduced conditions at Arlit-Akouta around 50 Ma. At Imouraren, younger uraninites formed between 34 and 8 Ma under locally reduced conditions, and were followed by secondary U-minerals from 21 Ma up to 3--1.6 Ma during supergene events. These ages are close or superimposed with the main oxidation stages, affecting West Africa during the Cenozoic, and attest of water table oscillations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Klaessens_etal2021,

title = {Highly siderophile element and Os isotope results from the structurally atypical Batin dunite in the Wadi Tayin massif of the Oman ophiolite},

author = {D. Klaessens and L. Reisberg and D. Jousselin and Oman Drilling Project Science Team},

doi = {10.1029/2021JB021977},

year  = {2021},

date = {2021-01-01},

journal = {JGR Solid Earth},

abstract = {Dunites in ophiolites form by pyroxene dissolution and olivine precipitation during meltperidotite interaction. We present structural and geochemical data on peridotites from the Batin region (Wadi Tayin massif) of the Oman ophiolite, where an exceptionally large (�`u9.5 km long) dunite body was sampled by the ICDP Oman Drilling Project (BA4A borehole). 900--1,200 m beneath the petrological Moho, this dunite is overlain by harzburgite hosting pyroxene-depleted and pyroxene-rich bands. Highly siderophile elements (HSEs) and Os isotopes, excellent tracers of melt flow through peridotites, were measured in dunites and interspersed harzburgites from BA4A borehole. The Batin dunite is structurally and chemically distinct from dunites from the Moho Transition Zone and basal section of the ophiolite, resembling instead sparse dunite veins in the main mantle section. Batin dunites have fairly uniform Os, Ir, and Ru abundances, but Pd and Pt contents increasing with depth. One deep dunite sample has initial 187Os/188Os more radiogenic than MORB. Though the limited number of data demands prudence, we suggest that the Batin dunite formed from a large pulse of radiogenic melts, whose flow was impeded �`u1,200 m below the Moho. As these melts ascended, they may have lost their radiogenic character and relative Pt and Pd enrichment through interaction with peridotites, which have much higher HSE contents than melts. Such interaction would also diminish the under-saturation in pyroxene of the melts, eliminating their capacity to sufficiently dissolve the pyroxene of the host harzburgite to form dunite, thus explaining the upper limit of the dunite at �`u900 m.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reisberg2021,

title = {Osmium isotope constraints on formation and refertilization of the non-cratonic continental mantle lithosphere},

author = {L. Reisberg},

doi = {10.1016/j.chemgeo.2021.120245},

year  = {2021},

date = {2021-01-01},

journal = {Chemical Geology},

volume = {574},

pages = {120245},

abstract = {It is increasingly accepted that many lherzolites in the lithospheric mantle formed by refertilization of depleted harzburgites, rather than by small degrees of melt extraction from fertile precursors. Such refertilization is often assumed to be linked to tectonic events unrelated to and much younger than the original partial melting episodes that left the depleted harzburgitic residues. Osmium isotopes provide a means of testing this assumption. Data for 187Os/188Os are now available from more than 50 studies of peridotites from the non-cratonic lithospheric mantle, including both xenoliths in alkali basalts and mantle tectonites of subcontinental affinity. The results from these studies confirm the long-recognized observation that whole rock Os isotope compositions are frequently correlated with indices of peridotite fertility such as Al2O3 content, with \>50% of the samples having 187Os/188Os ratios plotting within textpm1.5% of correlation lines between the estimated Primitive Upper Mantle (PUM) composition and the least radiogenic sample in each suite. A simple melt percolation model was developed that shows that such trends cannot result from direct precipitation of exsolved radiogenic sulfides, because any Os initially present in the circulating magma would be trapped by sulfides at the very bottom of the column, due to the extreme chalcophility of this element. Refertilized peridotites higher in the column would thus have unradiogenic Os compositions. The absence of fertile lherzolites with unradiogenic Os isotope compositions, the expected products of percolation of young melts through ancient harzburgites, argues that this process is extremely rare. Instead, the addition of Re during melt percolation occuring soon after harzburgite depletion would produce correlations between Re/Os and Al2O3 that with time would develop into correlations between 187Os/188Os and Al2O3 passing through the PUM composition. Such correlations would be linear, as observed, if DsRuelf/sil is 400, the approximate value predicted for this parameter for FeO-rich magmas at fO2 and fS2 values appropriate for non-arc mantle melting conditions. This perspective is fully consistent with the substantial variation in 187Os/188Os ratios found among sulfides taken from individual hand samples, if radiogenic ingrowth over time is associated with extensive, but incomplete, diffusive reequilibration. The conclusion that refertilization must follow soon after harzburgite formation has several implications. First, it suggests that the original melt depletion episodes are causally linked to the subsequent refertilization, which could result from percolation of the remaining melts through the cooling lithosphere. Second, early refertilization has consequences for the long-term stability of the lithosphere, since lherzolites are denser rocks than harzburgites. A final observation is that the systematic correlations between Os isotope compositions and fertility indices observed in most non-cratonic peridotite suites are unlikely to form in suprasubduction settings, where melts often carry ultramafic xenoliths with radiogenic and chaotic 187Os/188Os ratios. Instead, extensive melting above a mantle plume, followed soon after by refertilization with remaining melts as the plume cools, could explain the observed systematics. This newly formed mantle lithosphere could then be tectonically juxtaposed beneath continental crust formed above subduction zones},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reisberg+Zimmermann2021,

title = {Optimisation of 186Os/188Os measurements by N-TIMS using amplifiers equipped with 1013 $\Omega$ resistors},

author = {L. Reisberg and C. Zimmermann},

doi = {doi:10.1111/ggr.12371},

year  = {2021},

date = {2021-01-01},

journal = {Geostandards and Geoanalytical Research},

abstract = {Analysis of 186Os/188Os variations in most natural samples is hampered by their low Os mass fractions (usually \< 100 pg g-1), requiring Os separation from up to a kilogram of powder to obtain high precision measurement results. Recently developed amplifiers equipped with 1013 $\Omega$ feedback resistors improve the signal to noise ratio by an order of magnitude, allowing acquisition of high precision data (2SE \< 50 ppm) from 186Os16O3 ?\u{I} ion beams of 40 fA and thus analysis of less material ( 10--500 g). Factors controlling the uncertainty of 186Os/188Os N-TIMS measurement results, using a mixed array of 1013 and 1011 $\Omega$ amplifiers, include isobaric interferences, baseline variability, gain calibration, decay time corrections and oxygen isotope composition variations. Isobaric interferences present the greatest challenges, but these can be largely overcome by using double Pt filaments and periodically monitoring interferences during each measurement. The optimised procedures produce 186Os/188Os ratios with precisions close to the theoretical limits imposed by counting statistics and Johnson--Nyquist electronic noise for ion beams of 10--70 fA. The intermediate measurement precision (85 ppm ; 2s) approaches theoretically expected values ( 50--80 ppm). This precision is sufficient to allow 186Os/188Os analyses of crustal rocks, for which relatively large variations are expected.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jousselin_etal2021,

title = {Formation of the Moho transition zone in the Oman ophiolite, and comparison with sub-Moho melt lenses at fast spreading ridges},

author = {D. Jousselin and A. Nicolas and F. Boudier and L. Reisberg and M. Henri and M. Nicolle},

doi = {10.1016/j.tecto.2021.229148},

year  = {2021},

date = {2021-01-01},

journal = {Tectonophysics},

volume = {821},

pages = {229148},

abstract = {Our knowledge of melt distribution in the lower crust and upper mantle at oceanic fast spreading centers is very limited. Evidence of melt accumulation, sometimes away from the axis, has been imaged and interpreted at the Moho of the East Pacific Rise ; but the detailed structures of these deep magma lenses remains much more difficult to unveil than that of the shallow axial melt lens at the top of the plutonic crust. Ophiolites offer on-land sections of oceanic lithosphere that can complement marine geological and geophysical observations. We present results of a geological survey of the Moho transition zone at a paleospreading center in the Oman ophiolite. We find that the thickness of this dunite-rich horizontal layer increases from a few meters at the axis to hundreds of meters 6km away from the axis, and is reduced to a few meters 2--3 km further away. The base of the Moho transition zone contains dunite and very depleted harzburgite with isotropic plagioclase and clinopyroxene impregnations, and stockwork-like magmatic breccia, indicative of episodic high melt fractions. We conclude that the melt-free dunite horizontal layer may stop the progression of ascending melt ; this lead to melt accumulation within the uppermost harzburgite beneath the Moho transition zone and forms the isotropic impregnations. As the melt dissolves the harzburgite orhtopyroxene, and is flushed to the top of the MTZ though the breccia, it leaves new dunite at the base of the Moho transition zone. Repetition of this process renders the Moho transition zone thicker as it moves away from the ridge axis, until it leaves the main area of mantle melt delivery. Then, tectonic thinning and intrusion of parts of the MTZ into the lower crust reduce the MTZ thickness. These processes seem coherent with several marine geophysical observations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Chernonozhkin_etal2020,

title = {Evaluation of rammelsbergite (NiAs2) as a novel mineral for 187Re-187Os dating and implications for unconformity-related U deposits},

author = {S. M. Chernonozhkin and J. Mercadier and L. Reisberg and B. Luais and C. Zimmermann and C. Morlot and L. Salsi and A. Lecomte and O. Rouer and M. Brouand and A. Doney and P. Ledru},

doi = {10.1016/j.gca.2020.04.011},

year  = {2020},

date = {2020-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {280},

pages = {85--101},

abstract = {Rammelsbergite (NiAs2) is often present in ore deposits worldwide in association with other arsenides, sulphides and sulfarsenides. This work demonstrates the value of the application of the Re-Os isotopic system to the dating of rammelsbergite. Using the example of the Cigar Lake uranium deposit (Athabasca Basin, Saskatchewan, Canada), our results show that rammelsbergite concentrates significant and variable amounts of Re when crystallizing, up to 1.6mgg-1, while incorporating minimal common Os. Such characteristics make this mineral an ideal target for Re-Os isotopic dating, by both isochron and model age methods. Remarkable agreement of the Re-Os age of the rammelsbergite with the U-Pb age of the uranium oxide grains found inside one of the massive rammelsbergite veins confirms the applicability of the method. The selected rammelsbergite samples from the Cigar Lake uranium deposit yield a187Re-187Os isochron age of 1239 +33/-20 Ma. These results challenge a long-standing petrogenetic model which postulates contemporaneous U oxide and Ni-Co-arsenide depositionin unconformity-related uranium deposits. The new Re-Os age of rammelsbergite veins indicates that arsenide crystallization postdated the deposition of the primary uranium oxides at 1461--1341 Ma, implying that uranium oxides and nickel arsenides,as well as other sulphides and sulfarsenides, were not precipitated contemporaneously during a single hydrothermal event as previously proposed. The187Re-187Os data suggest that crystallization of rammelsbergite and co-genetic sulphides, arsenides and sulfarsenides was linked to the ca. 1270 Ma Mackenzie magmatic event, marked by the emplacement of mafic dikes throughout the Canadian Shield, including in the area of the Athabasca Basin. This study therefore suggests a new hypothesis for the origin of nickel, cobalt, sulfur and arsenic in unconformity-related U deposits of the Athabasca Basin. More broadly,the successful application of the187Re-187Os rammelsbergite chronometer in this geological context suggests that its application in other ore deposit environments worldwide is likely to provide similar insights. In this respect, the187Re-187Os chronometer applied to rammelsbergite, and potentially to other arsenides and sulfarsenides, represents a valuable complement to molybdenite dating because it can be used in systems that lack molybdenite.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kelemen_etal2020,

title = {Proceedings of the Oman Drilling Project},

author = {P. Kelemen and J. M. Matter and D. A. H. Teagle and J. A. Coggon and Oman Drilling Project Science Team and L. France and M. Boulanger and D. Jousselin and D. Klaessens and L. Reisberg},

doi = {10.14379/OmanDP.proc.2020},

year  = {2020},

date = {2020-01-01},

journal = {College Station, TX (International Ocean Discovery Program},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marzoli_etal2019,

title = {The Central Atlantic Magmatic Province (CAMP) in Morocco},

author = {A. Marzoli and H. Bertrand and N. Youbi and S. Callegaro and R. Merle and L. Reisberg and M. Chiaradia and S. I. Brownlee and F. Jourdan and A. Zanetti and J. H. F. L. Davis and T. Cuppone and A. Mahmoudi and F. Medina and P. R. Renne and G. Bellieni and S. Crivellari and H. El Hachimi and M. K. Bensalah and C. M. Meyzen and C. tegner},

doi = {10.1093/petrology/egz021},

year  = {2019},

date = {2019-01-01},

journal = {Journal of Petrology},

volume = {60},

number = {5},

pages = {945--996},

abstract = {The Central Atlantic Magmatic Province (CAMP) is a large igneous province (LIP) composed of basic dykes, sills, layered intrusions and lava flows emplaced before Pangea break-up and currently distributed on the four continents surrounding the Atlantic Ocean. One of the oldest, best preserved and most complete sub-provinces of the CAMP is located in Morocco. Geochemical, geochronologic, petrographic and magnetostratigraphic data obtained in previous studies allowed identification of four strato-chemical magmatic units, i.e. the Lower, Intermediate, Upper and Recurrent units. For this study, we completed a detailed sampling of the CAMP in Morocco, from the Anti Atlas in the south to the Meseta in the north. We provide a complete mineralogical, petrologic (major and trace elements on whole-rocks and minerals), geochronologic (40Ar/39Ar and U--Pb ages) and geochemical set of data (including Sr--Nd--Pb--Os isotope systematics) for basaltic and basaltic--andesitic lava flow piles and for their presumed feeder dykes and sills. Combined with field observations, these data suggest a very rapid (\<0textperiodcentered3thinspaceMa) emplacement of over 95% of the preserved magmatic rocks. In particular, new and previously published data for the Lower to Upper unit samples yielded indistinguishable 40Ar/39Ar (mean age = 201textperiodcentered2thinspacetextpmthinspace0textperiodcentered8thinspaceMa) and U--Pb ages (201textperiodcentered57thinspacetextpmthinspace0textperiodcentered04thinspaceMa), suggesting emplacement coincident with the main phase of the end-Triassic biotic turnover (c.201textperiodcentered5 to 201textperiodcentered3thinspaceMa). Eruptions are suggested to have been pulsed with rates in excess of 10thinspacekm3/year during five main volcanic pulses, each pulse possibly lasting only a few centuries. Such high eruption rates reinforce the likelihood that CAMP magmatism triggered the end-Triassic climate change and mass extinction. Only the Recurrent unit may have been younger but by no more than 1thinspaceMa. Whole-rock and mineral geochemistry constrain the petrogenesis of the CAMP basalts. The Moroccan magmas evolved in mid-crustal reservoirs (7--20thinspacekm deep) where most of the differentiation occurred. However, a previous stage of crystallization probably occurred at even greater depths. The four units cannot be linked by closed-system fractional crystallization processes, but require distinct parental magmas and/or distinct crustal assimilation processes. EC-AFC modeling shows that limited crustal assimilation (maximum c.5--8% assimilation of e.g. Eburnean or Pan-African granites) could explain some, but not all the observed geochemical variations. Intermediate unit magmas are apparently the most contaminated and may have been derived from parental magmas similar to the Upper basalts (as attested by indistinguishable trace element contents in the augites analysed for these units). Chemical differences between Central High Atlas and Middle Atlas samples in the Intermediate unit could be explained by distinct crustal contaminants (lower crustal rocks or Pan-African granites for the former and Eburnean granites for the latter). The CAMP units in Morocco are likely derived from 5--10% melting of enriched peridotite sources. The differences observed in REE ratios for the four units are attributed to variations in both source mineralogy and melting degree. In particular, the Lower basalts require a garnet peridotite source, while the Upper basalts were probably formed from a shallower melting region straddling the garnet--spinel transition. Recurrent basalts instead are relatively shallow-level melts generated mainly from spinel peridotites. Sr--Nd--Pb--Os isotopic ratios in the CAMP units from Morocco are similar to those of other CAMP sub-provinces and suggest a significant enrichment of the mantle-source regions by subducted crustal components. The enriched signature is attributed to involvement of about 5--10% recycled crustal materials introduced into an ambient depleted or PREMA-type mantle, while involvement of mantle-plume components like those sampled by present-day Central Atlantic Ocean Island Basalts (OIB, e.g. Cape Verde and Canary Islands) is not supported by the observed compositions. Only Recurrent basalts may possibly reflect a Central Atlantic plume-like signature similar to the Common or FOZO components.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Masurel_etal2019,

title = {Intrusion-related affinity and orogenic gold overprint at the Paleoproterozoic Bonikro Au--(Mo) deposit (C^ote dtextquoterightIvoire, West African Craton)},

author = {Q. Masurel and N. Th\'{e}baud and A. Allibone and A. S. Andr\'{e}-Mayer and K. A. A. Hein and L. Reisberg and O. Bruguier and A. Eglinger and J. Miller},

doi = {10.1007/s00126-019-00888-2},

year  = {2019},

date = {2019-01-01},

journal = {Mineralium Deposita},

volume = {55},

pages = {1--24},

abstract = {The Bonikro gold deposit and satellite Hir\'{e} open pits are located at the southern tip of the Oum\'{e}-F\'{e}tt\'{e}kro granite--greenstone belt in C^ote dtextquoterightIvoire. Country rocks in the region have undergone polyphase deformation and prolonged arc magmatism during the Paleoproterozoic Eburnean orogeny. Intrusive host rocks at Hir\'{e} and Bonikro have been dated at 2180thinspacetextpmthinspace6 and 2086thinspacetextpmthinspace4 Ma (U--Pb on zircon), respectively. These plutonic bodies acted as favourable sites for fluid flow due to their brittle rheological characteristics. Gold mineralisation at Bonikro is hosted by (i) a sheeted quartz vein array characterised by an Au--W--Bi--Te--Ag metal association, in the cupola of a porphyritic granodiorite; and (ii) an overprinting swarm of fault-fill smoky quartz--(molybdenite) veins. Gold mineralisation at Hir\'{e} is shear-hosted and shares a similar relative timing with the latter set of auriferous veins. This second phase of gold mineralisation occurred during a period of transcurrent tectonics late in the Eburnean tectono-magmatic history, soon after the cessation of compressional deformation. It is responsible for the bulk of gold resources in the region (e.g. Bonikro, Hir\'{e}, Agbahou) and has been dated at 2074thinspacetextpmthinspace16 Ma (Re--Os on molybdenite). The integration of structural--paragenetic relationships with high precision dating of magmatic and hydrothermal events highlights the superposition of late Eburnean orogenic gold mineralisation on an earlier intrusion-related gold system linked to the local emplacement of a porphyritic granodiorite at Bonikro and illustrates the genetic diversity of Paleoproterozoic granitoid-hosted gold mineralisation in the West African Craton. It also further supports that gold mineralisations in the West African Craton occurred diachronously throughout the Eburnean orogeny through a variety of deposit types including Au-skarn, intrusion-related Au, orogenic Au, and porphyry Cu--Au.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Morino_etal2018,

title = {Differentiation mechanisms of the early Hadean mantle: Insights from combined 176 Hf- 142,143 Nd signatures of Archean rocks from the Saglek Block},

author = {P. Morino and G. Caro and L. Reisberg},

doi = {10.1016/j.gca.2018.08.026},

year  = {2018},

date = {2018-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {240},

pages = {43--63},

abstract = {Positive 142Nd anomalies in Eoarchean rocks provide evidence for early (4.40 textpm 0.03 Ga ; Morino et al., 2017) depletion of Earthtextquoterights mantle. This model age lies within errors of the Pb-Pb textquotelefttextquoteleftage of the Earthtextquoterighttextquoteright (Connelly and Bizzarro, 2016), and is similar to model ages inferred for crystallization of the lunar mantle (McLeod et al., 2014), implying that this large-scale event may reflect crystallization of a magma ocean following the Moon-forming impact. However, differentiation mechanisms responsible for the formation of this early depleted mantle reservoir and the depth at which it formed cannot be constrained from the Sm-Nd isotope system alone, because the magnitude of Sm/Nd fractionation during partial melting or fractional crystallization shows little dependence on pressure-controlled changes in mantle mineralogy. In contrast, the Lu-Hf isotope system is highly dependent on mineralogy, notably the presence or absence of garnet, an upper mantle phase, and thus may be used to constrain the pressure of fractionation. This study provides the first 176Lu-176Hf isotopic results on mafic and ultramafic rocks belonging to the Eoarchean (Nulliak) and Mesoarchean suites of the Saglek Block (northern Labrador, 3.2--3.9 Ga). The 176Lu-176Hf dating confirms the distinction between these two groups of rocks and provides ages consistent with those obtained from 147Sm-143Nd dating. The whole rock 176Lu-176Hf errorchrons yield ages and initial epsilon values of 3766 textpm 140 Ma, $epsilon$176Hfi = 6.0 textpm 2.5 and 3023 textpm 390 Ma, $epsilon$176Hfi = −0.3 textpm 2.5 for the Nulliak suite and the Mesoarchean suite respectively. The time-integrated 176Lu/177Hf for the sources of the Nulliak and the Mesoarchean suites considering a time of differentiation at 4.40 textpm 0.03 Ga are estimated to be 0.047 textpm 0.005 and 0.033 textpm 0.005, respectively. For the Mesoarchean samples, the combined 146,147Sm-142,143Nd and 176Lu-176Hf data are consistent with a near-chondritic mantle source. On the other hand, Nulliak ultramafic rocks were derived from a mantle reservoir with superchondritic Lu/Hf and Sm/Nd. The Nulliak parent reservoir, however, does not plot on the $epsilon$176Hf-$epsilon$143Nd mantle array defined by modern oceanic basalts. Instead, the Nulliak source more likely belongs to a distinct array defined by Eo- and Meso-Archean komatiites. These results are interpreted in the framework of a simple model of crystallization of a primordial magma ocean. It appears that the fractionation observed in the mantle source of Nulliak was most likely generated by crystallization of a garnet-bearing assemblage in the shallow mantle, above the transition zone rather than by perovskite fractionation in the lower mantle. To preserve this depleted reservoir from the rest of the hot and vigorously convecting mantle, the Nulliak mantle source may have been isolated either at the top of the mantle in a buoyant lithosphere or near the core-mantle boundary, with the latter setting being more consistent with the komatiitic nature of the erupted rocks. Given that the garnet signature argues for differentiation of the Nulliak source at relatively shallow depth (few hundred kilometers), its isolation in the deep mantle would require a cumulate overturn following crystallization of the magma ocean.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Callegaro_etal2017,

title = {Geochemical constraints provided by the Freetown layered complex (Sierra Leone) on the origin of high-ti Tholeiitic CAMP magmas},

author = {S. Callegaro and A. Marzoli and H. Bertrand and J. Blichert-Toft and L. Reisberg and G. Cavazzini and F. Jourdan and J. H. F. L. Davies and L. Parisio and R. Bouchet and A. Paul and U. Schaltegger and M. Chiaradia},

year  = {2017},

date = {2017-01-01},

journal = {Journal of Petrology},

volume = {58},

number = {9},

pages = {1811--1840},

abstract = {The Freetown Layered Complex (FLC) is a massive mafic layered intrusion cropping out along the coast of Sierra Leone. The present combined geochemical and geochronological (40Ar/39Ar on plagioclase: 201textperiodcentered7 textpm 0textperiodcentered7 and 202textperiodcentered3 textpm 2textperiodcentered3 Ma; U--Pb on baddeleyite: 198textperiodcentered794 textpm 0textperiodcentered048/0textperiodcentered071/0textperiodcentered22 Ma) study of the complex flags it as a high-Ti occurrence of the Central Atlantic Magmatic Province (CAMP). Sr--Nd--Pb--Os isotope data indicate that the FLC is unique with respect to previously studied CAMP occurrences, constituting a new isotopic end-member for this large igneous province (LIP). Notably, the contribution of ancient source(s) is required to explain its low 206Pb/204Pb and high 207Pb/204Pb. Although the internal isotopic variability of the FLC can be explained by modest assimilation (\<10%) of lower crustal (granulitic) material, represented by a xenolith found within the complex itself, an atypical mantle source is required to account for its unusual Pb isotopic composition. We also present the first Hf isotopic data measured to date for CAMP rocks, which, in the case of the FLC, show a restricted range in 176Hf/177Hf, overlapping the ocean island basalt and mid-ocean ridge basalt fields on the terrestrial array, and can further be used to characterize the FLC isotopic end-member. We propose that the FLC formed by mixing of a predominantly asthenospheric parental magma with small volumes (1--3%) of geochemically highly enriched lamproitic melts derived from the sub-continental lithospheric mantle in a geodynamic context in which a Proterozoic mobile belt (Rokelide) bordered an Archean craton (Man). Within the CAMP, similar isotopic compositions, in particular low 206Pb/204Pb and high 207Pb/204Pb, are found only in regions that were once contiguous with Sierra Leone. A comparable involvement of enriched components stored within the cratonic lithosphere may be envisaged for the high-Ti magmatism in the CAMP and two other LIPs of the South Atlantic realm, Karoo and Paran\'{a}--Etendeka. These Gondwana magmatic provinces share with other mantle-derived magmas from the South Atlantic Ocean enriched isotopic signatures (DUPAL, LOMU, EMI) of much debated origin. The present mantle source model for the FLC, CAMP, and neighbouring LIPs suggests ancient enriched subcontinental lithospheric mantle as a plausible conveyor of such isotopic signatures in the South and Central Atlantic.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Fontaine_etal2017,

title = {Geology of the world-class Kiaka polyphase gold deposit, West African Craton, Burkina Faso},

author = {A. Fontaine and A. Eglinger and K. Ada and A. S. Andr\'{e}-Mayer and L. Reisberg and L. Siebenaller and E. Le Mignot},

doi = {10.1016/j.jafrearsci.2016.11.017},

year  = {2017},

date = {2017-01-01},

journal = {Journal of African Earth Sciences},

volume = {126},

pages = {96--122},

abstract = {The Kiaka gold deposit is a major resource in West Africa, with measured and indicated resources of 124 Mt at 1.09 g/t Au (3.9 Moz) and inferred resources of 27 Mt at 0.83 g/t Au (0.8 Moz). Located within the Manga-Fada NtextquoterightGourma greenstone and plutonic belt in south of the Burkina Faso, the deposit is hosted by a metamorphosed volcano-sedimentary sequence of lithic-, quartz-biotite metagreywackes, aluminosilicate-bearing metapelites and garnet-orthopyroxene-bearing schists and volcanic units. Structural observations indicate four local deformation events: DK1, DK2 and DK3 and DK4. Respectively, these events are linked to regional D1 E-W compression, D2 NW-SE compression and lastly, D3- and D4-related reactivations along D2 shear zones. The S2 foliation and D2 shear zones are developed during lower amphibolite facies metamorphism whereas retrogression occurs during D3-4 reactivations along these shear zones at upper greenschist facies conditions. The emplacement of a dioritic intrusion, dated at 2140 textpm 7 Ma (Concordia U-Pb age on magmatic zircon), is interpreted to be contemporaneouswith sinistral displacement along mineralized, NE-trending D2 shear zones. The intersection of these shears zones and the Markoye shear zone (dextral-reverse D1 and sinistral-reverse D2 reactivations) controlled the final geometry of the host rocks and the ore zones. Four subparallel elongated ore bodies are mainly hosted within D2-related shear zones and some are developed in an apparent axial plane of a F2 isoclinal fold. Detailed petrographic studies have identified two main types of hydrothermal alteration associated with two stages of gold mineralization. The stage (1) corresponds to replacement zones with biotite and clinozoisite during the D2 event associated with pyrrhotite textpm pyrite, chalcopyrite (disseminated gold stage). The stage (2) occurs during reactivations of the D2-related auriferous shear zones (vein stage) and is characterized by diopside textpm actinolite D3 veins andveinlets and D4 pervasive muscovite, textpm chlorite, textpm calcite in quartz-carbonate vein selvages and associated with pyrrhotiteþarsenopyritetextpmelectrum, textpmnative gold and tellurobismuthite. The latter stage (2) could be divided into two sub-stages based on mineralogy and crosscutting relationship. A weighted average Re-Os pyrrhotite age at 2157 textpm 24 Ma (Re-Os age based on 3 replicates) constraints the timing of the disseminated gold stage and represents the first absolute age for gold mineralization in the Manga Fada NtextquoterightGourma area. The timing of gold at Kiaka may be also coeval with one of the two lode gold event at textasciitilde ca. 2.16e2.15 Ga and occurred concomitant with tectono-thermal activity during Eo-Eburnean orogeny.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{LeMignot_etal2017,

title = {Re-Os Geochronological Evidence for Multiple Paleoproterozoic Gold Events at the Scale of the West African Craton},

author = {E. Le Mignot and L. Reisberg and A. S. Andr\'{e}-Mayer and Y. Bourassa and A. Fontaine and J. Miller},

doi = {10.2113/econgeo.112.1.145},

year  = {2017},

date = {2017-01-01},

journal = {Economic Geology Geology},

volume = {112},

pages = {145--168},

abstract = {The Archean-Proterozoic craton of West Africa hosts numerous gold deposits, which are spatially and temporally related to the Eburnean orogeny that took place between 2250 and 1980 Ma, and included multiple deformation events. The majority of these gold deposits are located along shear zones. The structural historyis relatively well established for most gold deposits, but absolute timing of the mineralization is commonly lacking. Five deposits hosted in the Baoul\'{e}-Mossi domain, located in the southwestern part of the West African craton, were studied to better constrain timing of gold events: Nassara and Kiaka in Burkina Faso and Wassa, Damang, and Obuasi in southern Ghana. Gold mineralization was structurally characterized at each deposit, and dated by the Re-Os method on pyrite, arsenopyrite, and pyrrhotite grains that were coeval with the gold deposition. Combined structural and Re-Os geochronological constraints allow two groups of gold deposits to be distinguished. Early orogenic gold formed during the Eoeburnean orogeny, i.e., between 2190 and 2125 Ma, as represented by Kiaka1 at 2157 textpm 24 Ma, and Wassa1 at 2164 textpm 14 Ma. These early gold occurrences are expressed as early disseminated gold enrichment (1--3 g/t Au) at Kiaka, and gold hosted in folded and boudinaged quartz veins that are transposed along the primary S1 foliation at Wassa. These Re-Os ages on the early sulfides at Wassa andKiaka are significant because they definitively provide the first direct age constraints on gold-only Eoeburnean mineralization in the Birimian of West Africa.Late orogenic gold, hosted by brittle structures and with higher gold grades (up to 60g/t at Kiaka), formed during late Eburnean deformation (D3--D5 events) between 2120 and 2000 Ma, as represented by the Re-Os dating of these ores at Wassa at 2055 textpm 18 Ma and Obuasi at 2045 textpm 40 Ma. Similar-style ores dated at Nassara at2131 textpm 99 Ma and Damang at 2080 textpm 135 Ma, but both with large uncertainties, and an undated younger event at Kiaka, are also suggested to be part of this later mineralizing episode. The high uncertainties on the Nassara and Damang ages may be directly linked to the low rhenium and osmium contents of the studied samples.These results highlight the polyphase character of the widespread gold mineralization in the West African craton. Although the late stages of the Eburnean orogeny constitute a prolific period for the formation of highgradegold mineralization, identification of less well-studied early-stage gold deposits, which can also contain large quantities of gold, is critical for mineral exploration in the West African craton.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{LeMignot_etal2017_2,

title = {The Paleoproterozoic Copper-Gold Deposits of the Gaoua District, Burkina Faso: Superposition of Orogenic Gold on a Porphyry Copper Occurrence?},

author = {E. Le Mignot and L. Siebenaller and D. B\'{e}ziat and A. S. Andr\'{e}-Mayer and L. Reisberg and S. Salvi and G. V\'{e}lasquez and C. Zimmermann and A. Nar\'{e} and G. Franceschi},

doi = {10.2113/econgeo.112.1.99},

year  = {2017},

date = {2017-01-01},

journal = {Economic Geology, 100th Anniversary Volume},

volume = {112},

pages = {99--122},

abstract = {The Gaoua mining district, underlain by Paleoproterozoic volcanic and intrusive rocks of the Boromo-Goren greenstone belt in southern Burkina Faso, is a rare case where economic copper and gold resources occur together in the Birimian terrane of West Africa. The main country rock lithologies consist of flows and volcaniclasticsediments of basaltic to andesitic compositions. These are intruded by subvolcanic diorite and quartz diorite stocks and dikes, granophyre dikes and, less commonly, gabbroic dikes. The stocks are porphyritic in texture, locally brecciated, and characterized by development of a carbonate, anhydrite, and quartz stockworksystem. Structural observations, detailed petrography, and sulfide geochemistry reveal that copper and gold in the stockworks and surrounding altered rocks cannot be associated with the same mineralizing event. Copper mineralization, mainly in the form of chalcopyrite, is typically observed in hydrothermal breccia and is associated with early arsenic-poor and gold-free pyrite. The geochemistry of the plutonic rocks and associated basalts and andesites implies formation in an arc setting. Textural evidence indicates that gold mineralization is closelytied to a second generation of sulfides, with the later pyrite hosting visible gold and minor chalcopyrite that clearly postdates the copper ore. Analyses of these pyrites by LA-ICP-MS reveal compositions rich in Ag, As, Au, Bi, Cu, and Pb. Pyrite with this signature was only observed in local shear and fracture zones that crosscut the host rocks and copper-rich breccia. Therefore, our data indicate the strongly deformed and metamorphosed porphyry copper mineralization in the Gaoua district is overprinted by orogenic gold mineralization. Formation of the early porphyry copper deposit took place at 2165 textpm 24 Ma based upon Re-Os dating of the early pyrite; the age of the younger gold event, which is similar in style to that described throughout the West African craton, is not known but may be related to one of the lode gold episodes that are widespread through the West African craton at textasciitilde2150 and textasciitilde2100 to 2040 Ma. The Gaoua copper deposit, one of very few Precambrian porphyry copper deposits known in West Africa, formed in a volcanic-arc setting that predated the Eburnean orogeny in the Boromo-Goren greenstone belt.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Merle_etal2017,

title = {Mt Bambouto Volcano, Cameroon Line: Mantle Source and Differentiation of Within-plate Alkaline Rocks},

author = {R. Merle and A. Marzoli and F. T. Aka and J. M. Chiaradia and L. Reisberg and F. Catorina and F. Jourdan and P. R. Renne and J. Ntextquoterightni and J. B. Nyobe},

doi = {10.1093/petrology/egx041},

year  = {2017},

date = {2017-01-01},

journal = {Journal of Petrology},

volume = {58},

number = {5},

pages = {933--962},

abstract = {The Late Cretaceous--Quaternary Cameroon Volcanic Line (CVL) is a 1600 km long chain of volcanoes that straddles the continent--ocean boundary and extends from the Gulf of Guinea to the interior of the African continent. The magmatic activity started at 70 Ma and has continued until the present. The products of this magmatic activity are distinctive in terms of petrology and isotope geochemistry, the variety of volcanic rocks ranging from ultrabasic, alkaline to sub-alkaline lavas to highly evolved alkaline lavas with isotopic compositions indicating complex combinations of both sub-lithospheric (HIMU, EM, DMM) and lithospheric components (sub-continental lithospheric mantle and crust). We conducted a petrological and geochemical study of a set of volcanic rocks, sampled from the rim and interior of the Miocene Mt Bambouto caldera, one of the 12 main volcanic centres of the CVL. The rocks were analysed for their whole-rock major and trace element contents, 40Ar/39Ar ages and whole-rock Sr--Nd--Pb--Os isotopic compositions. Phonolites and quartz-trachytes of the Mt Bambouto caldera are derived by fractional crystallization of highly alkaline and moderately alkaline parental basic magmas, respectively. Assimilation of the shallow crust has affected both alkaline and subalkaline magmas, suggesting that the petrogenesis of the differentiated rocks cannot be explained by crustal contamination alone. Only minor amounts (usually less than 5%) of assimilation of upper crustal silicic rocks from the local Pan-African basement are required to produce the most differentiated compositions. The rocks with the highest crustal contribution are Q-normative trachytes from peripheral cones, as well as one Ne-trachyte. Mt Bambouto basic--ultrabasic rocks, including basanites and alkali-basalts with high 187Os/188Osi, might have experienced some crustal contamination, but it must have been a limited process. Some Mt Bambouto ultrabasic to basic rocks show large ion lithophile element enrichment, notably of Sr,Ba and P compared with Zr. These samples also have relatively radiogenic Sr and unradiogenic Pb isotopic compositions. Such compositions are similar to those of the high-Sr group identified by previous studies. Most of the basic rocks do not show such characteristics and are identified as a low-Sr group. We interpret the geochemical characteristics of the high-Sr group as resulting from the partial melting of a depleted mantle (DMM-like) peridotite source containing pyroxenite veins that had interacted with carbonatitic fluids. To test this hypothesis, we used a new modelling approach based on Monte Carlo simulation; this method has the advantage of deciphering how different mantle components interacted through time. Our modelling confirms the plausibility of a three-component source. In addition, it suggests that the carbonatitic fluid first mixed with thepyroxenititic component and the resulting melt interacted with a DMM-like mantle. Both high-Sr and low-Sr groups can be produced by such a mixing scenario but with a stronger contribution of the carbonatitic fluid for the high-Sr group. At the time of melting, these source components could have been located in a metasomatized region of the sublithospheric mantle (uppermost section of the asthenosphere) or in the sub-continental lithospheric mantle.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Morino_etal2017,

title = {Chemical stratification in the post-magma ocean Earth inferred from coupled 146,147Sm--142,143Nd systematics in ultramafic rocks of the Saglek block (3.25--3.9 Ga; northern Labrador, Canada},

author = {P. Morino and G. Caro and L. Reisberg and A. Schumacher},

doi = {10.1016/j.epsl.2017.01.044},

year  = {2017},

date = {2017-01-01},

journal = {Earth and Planetary Science Letters},

volume = {463},

pages = {136--150},

abstract = {The coupled 146,147Sm--142,143Nd chronometer has the potential to provide precise constraints on both the age and the composition of silicate reservoirs generated by magma ocean processes on accreting planets. Application of this chronometer to early Earth differentiation, however, is made difficult by the poor preservation and complex geological history of Eoarchean rocks hosting 142Nd anomalies, which often prevents accurate determination of their initial 143Nd/144Nd ratios. In order to better constrain the chronological aspects of Earthtextquoterights formation, we investigated the 146,147Sm--142,143Nd systematics of well-preserved mafic/ultramafic enclaves of the Archean Saglek block of northern Labrador (3.25--3.9Ga). Our results show that two distinct ultramafic suites are present within the Hebron/Saglek fjords region. The first group of samples, with $mu$142Nd=1.6 textpm2.8 and $epsilon$143Ndi=0.4 textpm0.4, yields a whole-rock isochron age of 3365 textpm100 Ma and is tentatively suggested to be associated with the Mesoarchean Upernavik formation. The second group, with $mu$142Nd= 8.6 textpm3.3ppm and $epsilon$143Ndi=1.4 textpm0.6, yields an Eoarchean date of 3782 textpm93 Ma, and is assigned to the Nulliak assemblage. Application of coupled 146,147Sm--142,143Nd chronometry to the Nulliak suite yields a model age of differentiation of 4.40+0.05−0.06Ga, and a corresponding (147Sm/144Nd) source ratio of 0.211 textpm0.007 for the early depleted mantle. These estimates are remarkably similar to those obtained for a tholeiitic lava of the Abitibi greenstone belt (Theotextquoterights flow, 2.7Ga) based on the 142,143Nd dataset of Debaille et al.(2013). Viewed in conjunction with previous 142,143Nd data, our results provide a precise estimate of the age of primordial differentiation of Earthtextquoterights mantle, 160+30−20Myrafter formation of the solar system. This chronological constraint, combined with evidence for late solidification of the lunar magma ocean, strongly supports a young age for the giant impact and the Earth--Moon system. Further, the similarity of 146,147Sm--142,143Nd model ages and (Sm/Nd) source ratios inferred for Nulliak, Isua and Theotextquoterights flow suggests that their parent magmas were derived from a common mantle reservoir. This early depleted domain appears to have evolved as a closed-system on a multi-billion year timescale despite efficient mixing in the hot Hadean/Archean mantle. We thus propose that the occurrence of positive 142Nd anomalies in the Archean rock record reflects episodic melting of a depleted reservoir otherwise isolated from the convective system, rather than progressive homogenization of a highly depleted Hadean mantle.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Rossi_etal2017,

title = {Isotopic and geochemical constraints on lead and fluid sources of the Pb-Zn-Ag mineralization in the polymetallic Tighza-Jbel Aouam district (central Morocco), and relationships with the geodynamic context},

author = {M. Rossi and D. Gasquet and A. Cheilletz and L. Tarrieu and H. Bounajma and T. Mantoy and L. Reisberg and E. Deloule and P. Boulvais and P. Burnard},

doi = {10.1016/j.jafrearsci.2016.08.011},

year  = {2017},

date = {2017-01-01},

journal = {Journal of African Earth Sciences},

volume = {127},

pages = {194--210},

abstract = {The WAu, PbZnAg, and SbBa mineralizations of the polymetallic Tighza-Jbel Aouam district (central Meseta, Morocco), are hosted in Paleozoic rocks surrounding late-Carboniferous granitic stocks. The PbZnAg Tighza deposit formed at 254 textpm 16 Ma, and is clearly disconnected from the late-Variscan WAu deposit (295-280 Ma). The PbZnAg mineralization precipitated from a complex hydrothermal fluid. It displays air-normalized 3He/4He ratio (0.018--0.103) typical of the upper crust. This crustal component is confirmed by the oxygen and carbon isotope compositions ($delta$18O = +19 to +25texttenthousand ; $delta$13C = −3.6 to −11.2texttenthousand) and the ɛNd values (−4.84 to −9.01) of gangue carbonates, which show mixing of (i) fluids that have interacted with late-Carboniferous magmatic rocks, and (ii) fluids in equilibrium with the Paleozoic metasediments. In addition, the PbZnAg mineralization has 40Ar/36Ar values in the range 284--315 typical of a meteoric fluid. The radiogenic Pb isotopic compositions (207Pb/204Pb = 15.70--15.80 and 206Pb/204Pb = 18.30--18.50) suggest leaching of Pb from the surrounding Paleozoic metasediments and late-Variscan granites, whereas the low radiogenic signatures (207Pb/204Pb = 15.40 and 206Pb/204Pb = 18.05) provide evidence of a deeper source attributed to the lower crust.Crustal thinning related to extensional tectonics in late-Permian and Early-Triassic lead to high-K calc-alkaline to alkaline magmatic activity, which is evidenced by a dense SW-NE-trending dike network that pre-dated the Atlantic Ocean opening (early Liassic times). This magmatic event induced a regional heat flux increase that triggered the circulation of a complex hydrothermal fluid, which has a strong crustal component, but also a meteoric and a lower crustal components. The polymetallic district of Tighza-Jbel Aouam thus results from superposition of an intrusion related porphyry-gold mineralization (WAu, 286 Ma) followed by a PbZnAg epithermal mineralization (254 Ma), during two distinct magmatic-hydrothermal events.The proposed metallogenic model for the PbZnAg Tighza-Jbel Aouam deposit provides new constraints for the PbZnAg exploration in the Moroccan Meseta. Exploration targets must take into account the following geological features : (i) Permo-triassic high-K calk-alkaline to alkaline dikes, (ii) extensional tectonics and reactivation of ancient crust-scale faults and shear zones, and (iii) Paleozoic series containing organic matter (e.g., black shales) subjected to low grade metamorphism (e.g., greenschist facies).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{vanderMeer_etal2017,

title = {Preservation of an Archaean whole rock Re-Os isochron for the Venetia lithospheric mantle: Evidence for rapid crustal recycling and lithosphere stabilisation at 3.3 Ga},

author = {Q. H. A. Meer and M. Klaver and L. Reisberg and A. J. V. Riches and G. R. Davies},

doi = {10.1016/j.gca.2017.05.004},

year  = {2017},

date = {2017-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {216},

pages = {242--263},

abstract = {Re-Os and platinum group element analyses are reported for peridotite xenoliths from the 533 Ma Venetia kimberlite cluster situated in the Limpopo Mobile Belt, the Neoarchaean collision zone between the Kaapvaal and Zimbabwe Cratons. The Venetian xenoliths provide a rare opportunity to examine the state of the cratonic lithosphere prior to major regional metasomatic disturbance of Re-Os systematics throughout the Phanerozoic. The 32 studied xenoliths record Si-enrichment that is characteristic of the Kaapvaal lithospheric mantle and can be subdivided into five groups based on Re-Os analyses. The most pristine group I samples (n = 13) display an approximately isochronous relationship and fall on a 3.28 textpm 0.17 Ga (95 % conf. int.) reference line that is based on their mean TMA age. This age overlaps with the formation age of the Limpopo crust at 3.35--3.28 Ga. The group I samples derive from �`u50 to �`u170 km depth, suggesting coeval melt depletion of the majority of the Venetia lithospheric mantle column. Group II and III samples have elevated Re/Os due to Re addition during kimberlite magmatism. Group II has otherwise undergone a similar evolution as the group I samples with overlapping 187Os/188Os at eruption age: 187Os/188OsEA, while group III samples have low Os concentrations, unradiogenic 187Os/188OsEA and were effectively Re-free prior to kimberlite magmatism. The other sample groups (IV and V) have disturbed Re-Os systematics and provide no reliable age information. A strong positive correlation is recorded between Os and Re concentrations for group I samples, which is extended to groups II and III after correction for kimberlite addition. This positive correlation precludes a single stage melt depletion history and indicates coupled remobilisation of Re and Os. The combination of Re-Os mobility, preservation of the isochronous relationship, correlation of 187Os/188Os with degree of melt depletion and lack of radiogenic Os addition puts tight constraints on the formation and subsequent evolution of Venetia lithosphere. First, melt depletion and remobilisation of Re and Os must have occurred within error of the 3.28 Ga mean TMA age. Second, the refractory peridotites contain significant Re despite recording \>40 % melt extraction. Third, assuming that Si-enrichment and Re-Os mobility in the Venetia lithospheric mantle were linked, this process must have occurred within �`u100 Myr of initial melt depletion in order to preserve the isochronous relationship. Based on the regional geological evolution, we propose a rapid recycling model with initial melt depletion at �`u3.35 Ga to form a tholeiitic mafic crust that is recycled at �`u3.28 Ga, resulting in the intrusion of a TTG suite and Si-enrichment of the lithospheric mantle. The non-zero primary Re contents of the Venetia xenoliths imply that TRD model ages significantly underestimate the true depletion age even for highly depleted peridotites. The overlap of the �`u2.6 Ga TRD ages with the time of the Kaapvaal-Limpopo collision is purely fortuitous and has no geological significance. Hence, this study underlines the importance of scrutiny if age information is to be derived from whole rock Re-Os analyses.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Licht_etal2016,

title = {Cenozoic evolution of the central Myanmar drainage system: insights from sediment provenance in the Minbu Sub-Basin},

author = {A. Licht and L. Reisberg and C. France-Lanord and Aung Naing Soe and J. J. Jaeger},

doi = {10.1111/bre.121082108},

year  = {2016},

date = {2016-01-01},

journal = {Basin Research},

volume = {28},

pages = {237--251},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Luguet+Reisberg2016,

title = {Highly siderophile element and 187Os signatures in non-cratonic basalt-hosted peridotite xenoliths: Unravelling the origin and evolution of the post-Archean lithospheric mantle},

author = {A. Luguet and L. Reisberg},

year  = {2016},

date = {2016-01-01},

journal = {Reviews in Mineralogy and Geochemistry},

volume = {81},

pages = {305--367},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nicolle_etal2016,

title = {Major and trace element and Sr and Nd isotopic results from mantle diapirs in the Oman ophiolite: Implications for off-axis magmatic processes},

author = {M. Nicolle and D. Jousselin and L. Reisberg and D. Bosch and A. Stephant},

doi = {10.1016/j.epsl.2015.12.005},

year  = {2016},

date = {2016-01-01},

journal = {Earth and Planetary Science Letters},

volume = {437},

pages = {138--149},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reisberg_etal2016,

title = {Reply to the comment by Wu et al. (2016) on textquotelefttextquoteleft Behavior of Re and Os during contact between an aqueous solution and oil: Consequences on the Re-Os geochronometer applied to petroleumtextquoterighttextquoteright},

author = {L. Reisberg and R. Michels and F. Mahdaoui},

doi = {10.1016/j.gca.2016.04.014},

year  = {2016},

date = {2016-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {2016},

number = {186},

pages = {348--350},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mahdaoui_etal2015,

title = {Behavior of Re and Os during contact between an aqueous solution and oil: Consequences for the application of the Re--Os geochronometer to petroleum},

author = {F. Mahdaoui and R. Michels and L. Reisberg and M. Pujol and Y. Poirier},

doi = {10.1016/j.gca.2015.02.009},

year  = {2015},

date = {2015-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {158},

pages = {1--21},

abstract = {Several recent studies have raised the exciting possibility that oils can be dated using the Re--Os radioisotope system. However the exact nature of the events dated by this technique often remains unclear. Geochronologic interpretation of Re--Os data for oils is hampered by our limited knowledge of how these metals behave in petroleum systems. In particular, it is difficult to understand how isotopic homogenization, an essential prerequisite for the development of an isochronalrelationship, can be achieved at the scale of a petroleum basin. The mechanisms capable of fractionating the Re/Os ratio in a suite of oils are also poorly understood. For this reason, we have performed an experimental study aimed at investigating the behavior of Re and Os during a particularly widespread phenomenon in petroleum systems, the interaction of formation waters with oils during migration. Contact experiments between natural oils and aqueous solutions enriched in Re and/or Os were carried out for varying lengths of time (6 h to 5 months), at different temperatures (25--150 textdegreeC), over a wide range of metal concentrations in the enriched solution (0.001--100 lg/g for Re; 1 and 10 ng/g for Os). In addition, the effect of oil composition on Re--Os exchange at the water--oil interface was examined by testing two oils with very different properties.All of our results demonstrate that Re and Os are transferred massively and very rapidly from the aqueous solution to the organic phase. This is true regardless of temperature or oil composition. It is also true for a very wide range of metal concentrations in the aqueous solution, up to an apparent saturation level that exceeds natural concentrations in oils by several orders of magnitude. Given the efficiency of Re and Os transfer from water to oil demonstrated here, and assuming that our findings are applicable to natural conditions, water/oil ratios of only about 250 would be needed to explain the Re and Os contents of most oils, based on the measured concentrations of Re and Os in groundwaters. Thus transfer of Re and Os from formation waters could plausibly provide a source for these metals in oils. Waters from a given basin may have roughly homogeneous Os isotopiccompositions, approximating the average value of the source rocks. On the other hand, variable Re/Os ratios might be expected to develop, as a result of interaction with various phases (e.g. Fe--Mn oxides or authigenic pyrite) encountered by the water as it flows through the reservoir. If homogeneous 187Os/188Os ratios coupled with variable Re/Os ratios are transferred to the oils with which the waters come in contact, the isotopic geochronometer could be reset.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Muchez_etal2015,

title = {Diagenetic origin of the world-class Cu-Co deposit at Kamoto in the Central African Copperbelt},

author = {P. Muchez and A. S. Andr\'{e}-Mayer and H. A. El Desouki and L. Reisberg},

doi = {DOI10.1007/s00126-015-0582-3},

year  = {2015},

date = {2015-01-01},

journal = {Mineralium Deposita},

volume = {50},

pages = {437--447},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Andr-Mayer_etal2014,

title = {Re--Os geochronological constraints on the Dabolava mesothermal gold occurence, Madagascar: Implications for the Ikalamavony sub-domain deposition age},

author = {A. S. Andr\'{e}-Mayer and N. Ramiandrisoa and O. Vanderhaeghe and L. Reisberg and S. Rabeandrasana and C. Zimmermann},

doi = {10.1016/j.jafrearsci.2014.02.005},

year  = {2014},

date = {2014-01-01},

journal = {Journal of African Earth Sciences},

volume = {94},

pages = {119--127},

abstract = {New Re--Os ages for early concordant veins and later discordant veins in the Ikalamovony sub-domain of west-central Madagascar require respectively a Paleoproterozoic age for metasedimentary rocks and a Pan-African age for the orogenic type occurrences. Indeed, this paper focuses on Re--Os geochronologyof Dabolava gold occurrences, located in the Ikalamavony sub-domain, western central part of Madagascar. Two types of gold veins have been identified in this region; (i) type 1, centimetre-thick quartz veinlets, with diffuse contacts and concordant to the main regional foliation of the host amphibolites, part of the upper-Group of the Ikalamavony sub-domain; (ii) type 2, 30--50 cm-thick quartz veins variously transposed in shear zones affecting the Dabolava granodioritic orthogneisses, part of the Dabolava magmatic suite. These two types of veins with Au--Py assemblages have been sampled for Re--Os geochronology.The type 1 pyrite and electrum assemblage yields a Palaeoproterozoic age (1961 textpm 79 Ma) whereas the pyrite and electrum assemblage of discordant type 2 veins yields a Pan-African age (533 textpm 23 Ma). These ages record two main gold mineralization events that affected this crustal segment. Assuming that the Re--Os systematics were not perturbed by more recent events, the 1961 textpm 79 Ma ageobtained in this study on type 1 gold vein concordant in amphibolites favours a Palaeoproterozoic deposition age for the whole Ikalamavony sub-domain, both lower- and upper Groups. This age contrasts with the previously proposed Mesoproterozoic age for the deposition of the upper Group of the Ikalamavony sub-domain but is consistent with the Paleoproterozoic age (1800 Ma) deduced from detrital zirconages in the Ikalamavony quartzites located in the Ikalamavony lower Group. The Pan-African age obtained on the type 2 gold deposits is much younger than the emplacement age of the host granodiorite and precludes a porphyry-type model for this gold mineralization and rather favours an orogenic type with a deposition during the Pan-African orogeny},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Burnard_etal2014,

title = {An observed link between lithophile compositions and degassing of volatiles (He, Ar, CO2) in MORBs with implications for Revolatility and the mantle C/Nb ratio},

author = {P. Burnard and L. Reisberg and A. Colin},

doi = {10.1016/j.epsl.2014.03.045},

year  = {2014},

date = {2014-01-01},

journal = {Earth and Planetary Science Letters},

volume = {395},

pages = {159--167},

abstract = {There are systematic variations between relative noble gas abundances and lithophile tracers such as 87Sr/86Sr, $epsilon$Nd and La/Sm in a suite of basaltic glasses from the South East Indian Ridge (SEIR). 4He/40Ar⁎ (where 40Ar⁎ is 40Ar corrected for atmospheric contamination) correlates positively with 87Sr/86Sr and La/Sm but anticorrelates with $epsilon$Nd. The large range in 4He/40Ar⁎ observed in the glasses is due to fractionation during magmatic degassing caused by the very different solubilities of He and Ar in silicate liquids, whereas 87Sr/86Sr, $epsilon$Nd, La/Sm, etc. are insensitive to magmatic processes but rather reflect mantle heterogeneity. Thus, there is a curious situation in this suite of basalts where tracers of mantle heterogeneity (87Sr/86Sr, $epsilon$Nd, La/Sm, etc.) correlate with a tracer of magmatic volatile processes (4He/40Ar⁎). Here, we propose that textquotelefttextquoteleftenrichedtextquoterighttextquoteright mantle (with high La/Sm and 87Sr/86Sr, low $epsilon$Nd) also has a higher C concentration than textquotelefttextquoteleftdepletedtextquoterighttextquoteright mantle. Magmas derived from enriched mantle will therefore have higher initial C concentrations, leading to a greater fraction of CO2 degassed and thus a higher 4He/40Ar⁎ ratio on eruption. Simple solubility-determined fractional degassing models show that the range in 4He/40Ar⁎ observed in SEIR basaltic glasses can be generated if the mantle C concentration varies by a factor of 2 over the length of the ridge, consistent with independent estimates of C concentration heterogeneity in the MORB mantle. The correlations between lithophile tracers and 4He/40Ar⁎ can be reproduced by mixing between a depleted endmember with 87Sr/86Sr = 0.70275, $epsilon$Nd = 8.2 and [C] = 12 ppm and an enriched endmember with 87Sr/86Sr = 0.70360, $epsilon$Nd = 5 and [C] = 24 ppm, followed by degassing. The proposed degassing model allows us to estimate the initial C concentration (i.e. prior to degassing) of each SEIR basalt (for which Sr or Nd isotopes are available) ; using independent Nb concentration data (Mahoney et al., 2002), we show that C/Nb ratios prior to degassing along the SEIR are relatively constant, probably with a C/Nb ratio of 200textpm100. However, although the constancy of C/Nb in these samples is a robust conclusion, the estimated C/Nb ratio itself is model dependent. We also use these data to evaluate volatility of Re during degassing of MORBs ; Re is known to be moderately volatile during subaerial and shallow marine volcanism, although it is not known if this element is also volatile at conditions appropriate to MORB emplacement. Although there is a (poor) correlation between Re/Yb (Yb being a non-volatile element of similar apparent bulk compatibility to Re) and 4He/40Ar⁎ in these samples, it is more likely that this correlation results from Re/Yb variation in the mantle source and is not due to loss of Re during magmatic degassing.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Callegaro_etal2014,

title = {Enriched mantle source for the Central Atlantic magmatic province: New supporting evidence from southwestern Europe},

author = {S. Callegaro and C. Rapaille and A. Marzoli and H. Bertrand and M. Chiaradia and L. Reisberg and G. Bellieni and L. Martins and J. Madeira and J. Mata and N. Youbi and A. De Min and M. R. Azevedo and M. Khalil Bensalah},

doi = {10.1016/j.lithos.2013.10.021},

year  = {2014},

date = {2014-01-01},

journal = {Lithos},

volume = {188},

number = {2},

pages = {15--32},

abstract = {Remnants of the Central Atlantic magmatic province (CAMP), emplaced ca. 201 Ma during the rifting phases leading to Pangaea breakup, are still preserved in southwestern Europe (SWE) in the form of sills, dykes and lava flows. Low--Ti (TiO2 0.48--1.46 wt.%) tholeiitic basalts and basaltic andesites crop out as sills only in the Pyrenean area, as dykes (especially the Messejana--Plasencia dyke) from central Spain to the Atlantic coast, and as lava flows within sedimentary basins in Southern Portugal. Here we present new geochemical data (major and trace elements, mineral chemistry and combined Sr--Nd--Pb--Os analyses) on 132 samples, aiming to investigate the mantle source of these rocks and correlate them with magmatism from other areas of the CAMP. Crustal-like signatures in incompatible element patterns (Nb--Ta troughs, Pb peaks, generally shared by most CAMP rocks) and the enriched Sr--Nd--Pb isotopic characters (87Sr/86Sr200 Ma 0.70529--0.70657; 143Nd/144Nd200 Ma 0.51238--0.51225; 206Pb/204Pb200 Ma 18.15--18.48; 207Pb/204Pb200 Ma 15.57--15.68; 208Pb/204Pb200 Ma 37.99--38.52) apparently argue in favor of crustal assimilation playing an important role in the evolution of these magmas. However, the low initial 187Os/188Os values (0.1298 textpm 0.0056) as well as the restricted geochemical variations shown by SWE-CAMP rocks over such a large area limit the crustal assimilation of various Iberian lithologies to small amounts. We thus locate this enrichment in the mantle source, in the form of upper and lower crustal material recycled during earlier subduction-related events. This process, while imparting crustal signatures to incompatible elements and Sr--Nd--Pb isotopes, would not alter the Os isotopic signature, dominated by the peridotite. The mixed contribution of 3--7% of local upper (pelitic) and lower (felsic granulitic) crust is sufficient to enrich a depleted mantle source, which can be either the sub-SWE lithosphere or the upper depleted asthenosphere. Similar processes of crustal recycling within the upper mantle have been recognized to be responsible for the mantle source enrichment in other areas of the CAMP (Eastern North America). Geochemical correlations of the here studied tholeiites with CAMP rocks from other areas inscribe European basalts within the main pulse of CAMP magmatism.A subset of samples from Southern Portugal (here defined high-Sr dykes) shows different major and trace element geochemistry (e.g. Sr and CaO enrichment, SiO2 depletion) as well as more radiogenic 87Sr/86Sr200 Ma (0.70669--0.70749) and Pb isotopic ratios (e.g., 206Pb/204Pb200 Ma 18.55) at similar 143Nd/144Nd200 Ma (0.51232--0.51224). This reflects a different magmatic evolution for these rocks, dominated by the late-stage assimilation of 10--20% local carbonates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Licht_etal2014,

title = {Cenozoic evolution of the central Myanmar drainage system: insights from sediment provenance in the Minbu Sub-Basin},

author = {A. Licht and L. Reisberg and C. France-Lanord and A. N. Soe and J. J. Jaeger},

doi = {10.1111/bre.12108},

year  = {2014},

date = {2014-01-01},

journal = {Basin Research},

pages = {1--15},

abstract = {Located at the southern edge of the eastern Himalayan syntaxis, the Central Myanmar Basin (CMB) is divided into several Tertiary sub-basins that have been almost continuously filled since the Indo-Asia collision. They are currently drained by the Irrawaddy River, which flows down the eastern Tibetan Plateau and the Sino-Burman Ranges. Tracing sediment provenance from the CMB is thuscritical for reconstructing the past denudation of the Himalayan-Tibetan orogen; it is especially relevant since a popular drainage scenario involves the capture of the Tsangpo drainage system in Tibet by a precursor to the Irrawaddy River. Here, we document the provenance of sediment samples from the Minbu Sub-Basin at the southern edge of the CMB, which is traversed by the modern stream ofthe Irrawaddy River. Samples ranging in age from middle Eocene to Pleistocene were investigated using Nd isotopes, trace element geochemistry and sandstone modal compositions. Our data provide no evidence of a dramatic provenance shift; however, sandstone petrography, trace element ratios and isotopic values display long-term trends indicating a gradual decrease of the volcanic input andits replacement by a dominant supply from the Burmese basement. These trends are interpreted to reflect the progressive denudation of the Andean-type volcanic arc that extended onto the Burmese margin, along the flank of the modern Sino-Burman Ranges, where most of the post-collisional deformation of central Myanmar is located. Though our results do not exclude an ephemeral or diluted contribution from a past Tsangpo-Irrawaddy connection, sedimentation rates suggest thatthis hypothesis is unlikely before the development of a stable Tsangpo-Brahmaputra River in the Miocene. These results thus suggest that the central Myanmar drainage basin has remained restricted to the Sino-Burman Ranges since the beginning of the India-Asia collision.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Merle_etal2014,

title = {Sr, Nd, Pb and Os isotope systematics of CAMP Tholeiites from Eastern North America (ENA): Evidence of a subduction-enriched mantle source},

author = {R. Merle and A. Marzoli and L. Reisberg and H. Bertrand and A. Nemchin and M. Chiaradia and S. Callegaro and F. Jourdan and G. Bellieni and D. Kontak and J. Puffer and J. G. McHone},

doi = {doi:10.1093/petrology/egt063},

year  = {2014},

date = {2014-01-01},

journal = {Journal of Petrology},

volume = {55},

number = {1},

pages = {133--180},

abstract = {The Central Atlantic Magmatic Province (CAMP) is one of the largest igneous provinces on Earth, with an areal extent exceeding 107 km2. Here we document the geochemical characteristics of CAMP basalts from Triassic--Jurassic basins in northeastern USA and Nova Scotia (Canada). The CAMP rocks occur as lava flows, sills and dykes. All of our analysed samples show chemical characteristics typical of CAMP basalts with low titanium content, which include enrichment in the most incompatible elements and negative Nb anomalies. All the basalts also show enriched Sr--Nd--Pb initial (t = 201 Ma) isotopic compositions (206Pb/204Pbini. = 18textperiodcentered155--18textperiodcentered691, 207Pb/204Pbini. = 15textperiodcentered616--15textperiodcentered668, 208Pb/204Pbini. = 38textperiodcentered160--38textperiodcentered616, 143Nd/144Ndini. = 0textperiodcentered512169--0textperiodcentered512499). On the basis of stratigraphy, rare earth element (REE) chemistry and Sr--Nd--Pb isotope composition, three chemical groups are defined. The Hook Mountain group, with the lowest La/Yb ratios, initial 206Pb/204Pbini. \>18textperiodcentered5 and 143Nd/144Ndini. \> 0textperiodcentered51238, comprises all the lastest and upper stratigraphic units. The Preakness group, with intermediate La/Yb ratios, 206Pb/204Pbini. \> 18textperiodcentered5 and 0textperiodcentered51233 \> 143Nd/144Ndini. \> 0textperiodcentered51225, comprises the intermediate units. The Orange Mountain group has the highest La/Yb ratios and 143Nd/144Ndini. \< 0textperiodcentered51235 and involves all the earliest and stratigraphically lowest units, including the entire North Mountain basalts from Nova Scotia. In this last group, three sub-groups may be distinguished: the Rapidan sill, which has 206Pb/204Pbini. higher than 18textperiodcentered5, the Shelburne sub-group, which has 143Nd/144Ndini. \< 0textperiodcentered51225, and the remaining Orange Mt samples. With the exception of one sample, the Eastern North America (ENA) CAMP basalts display initial 187Os/188Os ratios in the range of mantle-derived magmas (\<0textperiodcentered15). Simple modelling shows that the composition of the ENA CAMP basalts cannot plausibly be explained solely by crustal contamination of oceanic island basalt (OIB), mid-ocean ridge basalt (MORB) or oceanic plateau basalt (OPB) magmas. Mixing of such magma compositions with sub-continental lithospheric mantle (SCLM)-derived melts followed by crustal contamination, by either assimilation--fractional crystallization (AFC) or assimilation through turbulent ascent (ATA) processes is somewhat more successful. However, this latter scenario does not reproduce the REE and isotopic composition of the ENA CAMP in a fully satisfactory manner. Alternatively, we propose a model in which asthenospheric mantle overlying a subducted slab (i.e. mantle wedge) was enriched during Cambrian to Devonian subduction by sedimentary material, isotopically equivalent to Proterozoic--Lower Paleozoic crustal rocks. Subsequently, after subduction ceased, the isotopic composition of this mantle evolved by radioactive decay for another 170 Myr until the CAMP magmatic event. Varying amounts and compositions of the incorporated sedimentary component coupled with radiogenic ingrowth over time can account for the main geochemical characteristics of the ENA CAMP (enriched incompatible element patterns, negative Nb anomalies, enriched Sr--Nd--Pb isotopic composition) and the differences between the three chemical groups.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Callegaro_etal2013,

title = {Upper and lower crustre cycling in the source of CAMP basaltic dykes from southeastern North America},

author = {S. Callegaro and A. Marzoli and H. Bertrand and M. Chiaradia and L. Reisberg and C. Meysen and G. Bellieni and R. E. Weems and R. Merle},

doi = {10.1016/j.epsl.2013.06.023},

year  = {2013},

date = {2013-01-01},

journal = {Earth and Planetary Science Letters},

volume = {376},

pages = {186--199},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Licht_etal2013_2,

title = {A palaeo Tibet--Myanmar connection? Reconstructing the Late Eocene drainage system of central Myanmar using a multi-proxy approach},

author = {A. Licht and C. France-Lanord and L. Reisberg and C. Fontaine and A. N. Soe and J. J. Jaeger},

doi = {10.1144/jgs2012-126},

year  = {2013},

date = {2013-01-01},

journal = {Journal of Geological Society, London},

volume = {170},

number = {6},

pages = {929--939},

abstract = {Strain resulting from the collision of India with Asia has caused fundamental changes to Asian drainage patterns, but the timing and nature of these changes are poorly understood. One frequently proposed hypothesis involves the connection of the palaeo Tsangpo drainage to a precursor to the Irrawaddy River of central Myanmar in the Palaeogene. To test this hypothesis, we studied the provenance of Palaeogene fluvioclastic sedimentary rocks that crop out in central Myanmar, namely the Late Middle Eocene--Early Oligocene Pondaung and Yaw Formations. Isotopic on bulk-rock and petrographic data indicate a primary magmatic arc source, and a secondary source composed of recycled, metamorphosed basement material. Although the exact location of both sources is hardly distinguishable because Burmese and Tibetan provinces share common lithological features, the presence of low-grade metamorphic fragments, the heterogeneity in Sr--Nd isotopic values of bulk sediments and westward-directed palaeoflow orientations indicate a proximal source area located on the eastern Asian margin. Central Myanmar was the locus of westward-prograding deltas opening into the Indian Ocean, supplied by the unroofing of an Andean-type cordillera that extended along the Burmese margin. We found no evidence to support a palaeo Tsangpo--Irrawaddy River, at least during the Late Eocene.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Maccali_etal2013,

title = {Geochemical signatures of sediments documenting Arctic sea-ice and water mass export through Fram Strait since the Last Glacial Maximum},

author = {J. Maccali and C. Hillaire-Marcel and J. Carignan and L. Reisberg},

doi = {doi.org/10.1016/j.quascirev.2012.10.029},

year  = {2013},

date = {2013-01-01},

journal = {Quaternary Science Reviews},

volume = {64},

pages = {136--151},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mahdaoui_etal2013,

title = {Effect of the progressive precipitation of petroleum asphaltenes on the Re-Os radioisotope system},

author = {F. Mahdaoui and L. Reisberg and R. Michels and Y. Hautevelle and Y. Poirier and J. P. Girard},

doi = {10.1016/j.chemgeo.2013.08.038},

year  = {2013},

date = {2013-01-01},

journal = {Chemical Geology},

volume = {358},

pages = {90--100},

abstract = {Recent studies (e.g., Selby and Creaser, 2005) have raised the intriguing possibility that the evolution of oil can be dated using the Re--Os radioisotope system. However, in order to understand which specific events are beingdated, it is essential to determine the processes that could create the range in the parent--daughter ratio necessary for the use of the geochronometer. One particularly important process in the evolution of petroleum is the sequential and progressive precipitation of asphaltenes during oil migration, mixing and reservoir filling. As asphaltenes are known to contain the near totality of the Re and Os present in oil, this event could potentially lead to the required fractionation of Re/Os ratios. Sequential asphaltene precipitation was performed in the laboratory with the aim of assessing the effect of progressive precipitation on relative and absolute Re and Os contents. The experiments were performed on two well preserved oils with distinct properties: one was a mediumdensity, sulfur-poor crude oil containing about 7% asphaltenes; the other a heavy, sulfur-rich oil containing about 20% asphaltenes. Bulk asphaltenes were extracted from each oil and dissolved in an organic solvent (dichloromethane). Starting with these bulk fractions, sequential precipitation into fractions of decreasing polarity was provoked by adding increasing quantities of precipitant (n-heptane or n-pentane). For both oils, the Re and Os concentrations of the successive asphaltene fractions decreased steadily during the progressive precipitation.However the Re/Os ratio remained constant, except at very high degrees of asphaltene precipitation. This suggests that natural asphaltene precipitation during the evolution of hydrocarbons in a petroleum system has very little effect on the Re/Os ratio. Thus asphaltene precipitation during the evolution of hydrocarbons in a petroleum system or during oil recovery is unlikely to perturb the Re--Os geochronometer. Conversely, asphaltene precipitation is probably not the process responsible for the Re/Os fractionation required to develop an isochron.The similarity of the concentration profiles with progressive precipitation obtained for Re and Os suggests that these metals have similar binding properties in asphaltenes. In contrast, V and Ni concentration profiles obtainedduring these experiments display a different character. Unlike Re and Os, which are hosted by the most polar asphaltenes, V and Ni are preferentially bound to asphaltenes of intermediate polarity. This suggests that Re and Os are not hosted by the same organic entities that carry V and Ni (e.g., metallo-porphyrins).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Maccali_etal2012,

title = {Pb isotopes and geochemical monitoring of Arctic sedimentary supplies and water mass export through Fram Strait since the Last Glacial Maximum},

author = {J. Maccali and C. Hillaire-Marcel and J. Carignan and L. Reisberg},

doi = {10.1029/2011PA002152.},

year  = {2012},

date = {2012-01-01},

journal = {Paleoceanography},

volume = {27},

number = {PA1201},

pages = {1--17},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Alard_etal2011,

title = {Volatile-rich metasomatism in Montferrier xenoliths (Southern France): Implications for the abundances of Chalcophile and highly siderophile elements in the subcontinental mantle},

author = {O. Alard and J. P. Lorand and L. Reisberg and J. L. Bodinier and J. M. Dautria and S. Y. OtextquoterightReilly},

doi = {10.1093/petrology/egr038},

year  = {2011},

date = {2011-01-01},

journal = {Journal of Petrology},

volume = {52},

number = {10},

pages = {2009--2045},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Merle_etal2011,

title = {40Ar/39Ar ages and Sr-Nd-Pb-Os geochemistry of CAMP tholeiites from Western Maranh~ao basin (NE Brazil): Implications for low and high-Ti basalt sources},

author = {R. Merle and A. Marzoli and H. Bertrand and L. Reisberg and C. Verati and C. Zimmermann and M. Chiaradia and G. Bellieni and M. Ernesto},

doi = {10.1016/j.lithos.2010.12.010},

year  = {2011},

date = {2011-01-01},

journal = {Lithos},

volume = {122},

pages = {137--151},

abstract = {The Central Atlantic Magmatic Province (CAMP), emplaced at the Triassic--Jurassic (T--J) boundary (textasciitilde200 Ma), is among the largest igneous provinces on Earth. The Maranh~ao basin in NE Brazil is located around 700 km inland and 2000 km from the site of the earliest Pangea disruption. The CAMP tholeiites occur only in thewestern part of the basin and have been described as low and high-Ti. Here we document the occurrence of two sub-groups among the high-Ti tholeiites in the Western Maranh~ao basin. The major and trace elements and the Sr--Nd--Pb isotopic ratios define three chemical groups corresponding to the low-Ti (TiO2b1.3 wt.%),high-Ti (TiO2textasciitilde2.0 wt.%) and evolved high-Ti (TiO2N3 wt.%) western Maranh~ao basin tholeiites (WMBT). The new 40Ar/39Ar plateau ages obtained on plagioclase separates for high-Ti (199.7textpm2.4 Ma) and evolved high-Ti WMBT (197.2textpm0.5 Ma and 198.2textpm0.6 Ma) are indistinguishable and identical to those of previouslyanalyzed low-Ti WMBT (198.5textpm0.8 Ma) and to the mean 40Ar/39Ar age of the CAMP (199textpm2.4 Ma). We also present the first Re--Os isotopic data for CAMP basalts. The low and high-Ti samples display mantle-like initial (187Os/188Os)i ranging from 0.1267 to 0.1299, while the evolved high-Ti samples are more radiogenic ((187Os/188Os)i up to 0.184) We propose that the high-Ti WMBT were derived from the sub-lithospheric asthenosphere, and contaminated during ascent by interaction with the subcontinental lithospheric mantle (SCLM). The evolved high-Ti WMBT were derived from the same asthenospheric source but experienced crustal contamination. The chemical characteristics of the low-Ti group can be explained by partial melting of the most fertile portions of the SCLM metasomatized during paleo-subduction. Alternatively, the low-Ti WMBT could be derived from the sub-lithospheric asthenosphere but the resulting melts may have undergone contamination by the SCLM. The occurrences of high-Ti basalts are apparently not restricted to the area of initial continental disruption which may bring into question previous interpretations such as those relating high-Ti CAMP magmatism to the initiation of Atlantic ridge spreading or as the expression of a deep mantle plume. We propose that the CAMP magmatism in the Maranh~ao basin may be attributed to local hotter mantle conditions due to the combined effects of edge-driven convection and large-scale mantle warming under the Pangea supercontinent. The involvement of a mantle-plume with asthenosphere-like isotopic characteristics cannot be ruled out either as one of the main source components of the WMBT or as a heat supplier.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Paul_etal2011,

title = {Behavior of osmium at the freshwater--saltwater interface based on Ganga derived sediments from the estuarine zone},

author = {M. Paul and L. Reisberg and N. Vigier and C. France-Lanord},

doi = {10.1029/2011GC003831},

year  = {2011},

date = {2011-01-01},

journal = {Geochemistry, Geophysics, Geosystems G3},

volume = {12},

number = {12},

pages = {Q12023},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reisberg_etal2011,

title = {Re and Os distribution and Os isotope composition of the Platreef at the Sandsloot--Mogolakwena mine, Bushveld complex, South Africa},

author = {L. Reisberg and M. Tredoux and C. Harris and A. Coftier and J. Chaumba},

doi = {10.1016/j.chemgeo.2010.12.021},

year  = {2011},

date = {2011-01-01},

journal = {Chemical Geology},

volume = {281},

pages = {352--363},

abstract = {Rhenium and Os concentrations and Os isotopic compositions were determined for a suite of previously characterized samples from a traverse across the Platreef at the Sandsloot--Mogolakwena mine of the Northern Limb of the Bushveld complex. The samples comprise five pyroxenites and five textquotelefttextquoteleftparapyroxenites,textquoterighttextquoteright contact rocks representing variable mixtures of calc--silicate country rocks and magmatic rocks. The isotopic data from the pyroxenites define a Re--Os regression line with an age (2011textpm51 Ma) that agrees within uncertainty with the accepted age for the Bushveld complex, whereas the parapyroxenite data scatter about this trend. The initial 187Os/188Os ratios of the pyroxenites (0.1820--0.1848) are similar to, but slightly more radiogenic than, previously published values for the Merensky Reef. Our preferred interpretation is that this section of the Platreef formed from a well mixed, crustally contaminated magma, genetically related to that which gave rise to the Merensky Reef. The Platreef parental magma may also have experienced minoradditional contamination by wall rock interaction during emplacement.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Paul_etal2010,

title = {Dissolved osmium in Bengal plain groundwater: Implications for the marine Os budget},

author = {M. Paul and L. Reisberg and N. Vigier and Y. Zheng and K. M. Ahmed and L. Charlet and M. R. Huq},

doi = {10.1016/j.gca.2010.02.034},

year  = {2010},

date = {2010-01-01},

journal = {Geochimica Et Cosmochimica Acta},

volume = {74},

number = {12},

pages = {3432--3448},

abstract = {We report osmium concentrations and isotopic compositions of 40 groundwater samples from the Bengal plain. Groundwaters have Os concentrations (16.9-191.5 pg/kg), about 5-10 times higher than those published for most rivers or seawater. Os-187/Os-188 varies widely (from 0.96 to 2.79) and is related to the isotopic signatures of the sediments constituting local aquifers. Os contents are correlated with those of soluble elements such as Sr, Mg, and Ca, suggesting that differing extents of solid-solution interaction explain most of the variation in measured Os concentrations. The covariation between Os and Sr allows us to estimate the mean Os content of Bengal groundwater (similar to 70 pg/kg). This concentration is too low to allow Bengal groundwater to significantly influence the marine Os isotopic composition, if likely fresh groundwater discharge rates to the Bay of Bengal are assumed. However, if Bengal groundwater Os concentrations are typical, the global Os groundwater flux would be expected to be around 180 kg/year, making it the second largest input of Os to the ocean after the river flux. Including this flux in the current Os marine budget, and assuming that this and other fluxes have remained constant with time, would decrease the calculated residence time of Os in the ocean by about 30%. (C) 2010 Elsevier Ltd. All rights reserved.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dera_etal2009,

title = {Water mass exchange and variations in seawater temperature in the NW Tethys during the Early Jurassic: Evidence from neodymium and oxygen isotopes of fish teeth and belemnites},

author = {G. Dera and E. Puc\'{e}at and P. Pellenard and P. Neige and D. Delsate and M. Joachimski and L. Reisberg and J. Martinez},

doi = {10.1016/j.epsl.2009.06.027},

year  = {2009},

date = {2009-01-01},

journal = {Earth and Planetary Science Letters},

volume = {289},

pages = {198--207},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Paul_etal2009,

title = {A new method for analysis of osmium isotopes and concentrations in surface and subsurface water samples},

author = {M. Paul and L. Reisberg and N. Vigier},

doi = {10.1016/j.chemgeo.2008.09.018},

year  = {2009},

date = {2009-01-01},

journal = {Chemical Geology},

volume = {258},

pages = {136--144},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reisberg_etal2009,

title = {Nucleosynthetic osmium isotope anomalies in acid leachates of the Murchison meteorite},

author = {L. Reisberg and N. Dauphas and A. Luguet and D. G. Pearson and R. Gallino and C. Zimmermann},

doi = {10.1016/j.epsl.2008.10.030},

year  = {2009},

date = {2009-01-01},

journal = {Earth and Planetary Science Letters},

volume = {277},

pages = {334--344},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zheng_etal2009,

title = {Re--Os systematics of the Raobazhai peridotite massifs from the Dabie orogenic zone, eastern China},

author = {L. Zheng and X. Zhi and L. Reisberg},

doi = {10.1016/j.chemgeo.2009.06.021},

year  = {2009},

date = {2009-01-01},

journal = {Chemical Geology},

volume = {268},

pages = {1--14},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Cardon_etal2008,

title = {Re-Os systematics of pyrite from the bolcana porhyry copper deposit, Apuseni Mountains, Romania},

author = {O. Cardon and L. Reisberg and A. S. Andr\'{e}-Mayer and J. Leroy},

doi = {10.2113/gsecongeo.103.8.1695},

year  = {2008},

date = {2008-01-01},

journal = {Economic Geology},

volume = {103},

number = {8},

pages = {1695--1702},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Najman_etal2008,

title = {The Paleogene record of Himalayan erosion: Bengal Basin, Bangladesh},

author = {Y. Najman and M. Bickle and M. BouDagher-Fadel and A. Carter and E. Garzanti and M. Paul and J. Wijbrans and E. Willet and G. Olivier and R. Parrish and S. H. Akhter and R. Allen and S. Ando and E. Chisty and L. Reisberg and G. Vezzoli},

doi = {10.1016/j.epsl.2008.04.028},

year  = {2008},

date = {2008-01-01},

journal = {Earth and Planetary Science Letters},

volume = {273},

number = {1-2},

pages = {1--14},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reisberg_etal2008,

title = {Re--Os results from ODP Site 801: Evidence for extensive Re uptake during alteration of oceanic crust},

author = {L. Reisberg and O. Rouxel and J. Ludden and H. Staudigel and C. Zimmermann},

doi = {10.1016/j.chemgeo.2007.07.01},

year  = {2008},

date = {2008-01-01},

journal = {Chemical Geology},

volume = {248},

pages = {256--271},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Oxburgh_etal2007,

title = {Climate-correlated variations in seawater 187Os/ 188Os over the past 200,000 yr: Evidence from the Cariaco Basin, Venezuela},

author = {E. Oxburgh and A. C. Pierson-Wickmann and L. Reisberg and S. Hemming},

doi = {10.1016/j.epsl.2007.08.033},

year  = {2007},

date = {2007-01-01},

journal = {Earth and Planetary Science Letters},

volume = {263},

number = {3-4},

pages = {246--258},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Solgadi_etal2007,

title = {The role of crustal anatexis and mantle-derived magmas in the genesis of synorogenic hercynian granites of the Livradois area, French Massif Central},

author = {F. Solgadi and J. F. Moyen and O. Vanderhaeghe and E. W. Sawyer and L. Reisberg},

year  = {2007},

date = {2007-01-01},

journal = {The Canadian Mineralogist},

volume = {45},

number = {3},

pages = {581--606},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gaffney_etal2005,

title = {Oxygen-osmium isotope systematics of West Maui lavas: a record of shallow-level magmatic processess},

author = {A. M. Gaffney and B. K. Nelson and L. Reisberg and J. Eiler},

doi = {10.1016/j.epsl.2005.07.027},

year  = {2005},

date = {2005-01-01},

journal = {Earth and Planetary Science Letters},

volume = {239},

pages = {122--139},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pucat_etal2005,

title = {Neodymium isotope evolution of NW Tethyan upper ocean waters throughout the Cretaceous},

author = {E. Puc\'{e}at and C. L\'{e}cuyer and L. Reisberg},

doi = {10.1016/j.epsl.2005.03.015},

year  = {2005},

date = {2005-01-01},

journal = {Earth and Planetary Science Letters},

volume = {236},

number = {3-4},

pages = {705--720},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reisberg_etal2005,

title = {Re-Os and S systematics of spinel peridotite xenoliths from east central China: Evidence for contrasting effects of melt percolation},

author = {L. Reisberg and X. Zhi and J. P. Lorand and C. Wagner and Z. Peng and C. Zimmermann},

doi = {10.1016/j.epsl.2005.09.010},

year  = {2005},

date = {2005-01-01},

journal = {Earth and Planetary Science Letters},

volume = {239},

pages = {286--308},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Asrat_etal2004,

title = {Petrology and isotope geochemistry of the Pan-African Negash Pluton, Northern Ethiopia: mafic-felsic magma interactions during the construction of shallow-level calc-alkaline plutons},

author = {A. Asrat and P. Barbey and J. Ludden and L. Reisberg and G. Gleizes and D. Ayalew},

doi = {10.1093/petrology/egh009},

year  = {2004},

date = {2004-01-01},

journal = {Journal of Petrology},

volume = {45},

number = {6},

pages = {1147--1179},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dauphas_etal2004,

title = {The cosmic Molybdenum-Ruthenium isotope correlation},

author = {N. Dauphas and A. M. Davis and B. Marty and L. Reisberg},

doi = {10.1016/j.epsl.2004.07.026},

year  = {2004},

date = {2004-01-01},

journal = {Earth and Planetary Science Letters},

volume = {226},

number = {3-4},

pages = {465--475},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Levresse_etal2004,

title = {Osmium, sulphur, and helium isotopic results from the giant Neoproterozoic epithermal Imiter silver deposit, Morocco: evidence for a mantle source},

author = {G. Levresse and A. Cheilletz and D. Gasquet and L. Reisberg and E. Deloule and B. Marty and K. Kyser},

doi = {10.1016/j.chemgeo.2004.02.004},

year  = {2004},

date = {2004-01-01},

journal = {Chemical Geology},

volume = {207},

number = {1-2},

pages = {59--79},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reisberg_etal2004,

title = {Highly siderophile element behavior in high temperature processes},

author = {L. Reisberg and O. Alard and J. P. Lorand and M. Ohnenstetter},

doi = {10.1016/j.chemgeo.2004.04.004},

year  = {2004},

date = {2004-01-01},

journal = {Chemical Geology},

volume = {208},

number = {1-4},

pages = {1--4},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reisberg_etal2004_2,

title = {Reliability of Os model ages in pervasively metasomatized continental mantle lithosphere: a case study of Sidamo spinel peridotite xenoliths (East African Rift, Ethiopia)},

author = {L. Reisberg and J. P. Lorand and R. M. Bedini},

doi = {10.1016/j.chemgeo.2004.04.008},

year  = {2004},

date = {2004-01-01},

journal = {Chemical Geology},

volume = {208},

number = {1-4},

pages = {119--140},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dauphas_etal2003,

title = {Short-lived p-nuclides in the early solar system and implications on the nucleosynthetic role of X-ray binaries},

author = {N. Dauphas and T. Rauscher and B. Marty and L. Reisberg},

doi = {10.1016/S0375-9474(03)00934-5},

year  = {2003},

date = {2003-01-01},

journal = {Nuclear Physics. A},

volume = {719},

pages = {287c-295c},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lorand_etal2003,

title = {Platinum-group elements and melt percolation processes in Sidamo spinel peridotite xenoliths, Ethiopia, East African rift},

author = {J. P. Lorand and L. Reisberg and R. M. Bedini},

doi = {10.1016/S0009-2541(02)00407-2},

year  = {2003},

date = {2003-01-01},

journal = {Chemical Geology},

volume = {196},

pages = {57--75},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Meisel_etal2003,

title = {Re-Os systematics of UB-N, a serpentinized peridotite reference material},

author = {T. Meisel and L. Reisberg and J. Moser and J. Carignan and F. Melcher and G. Br\"{u}gmann},

doi = {10.1016/S0009-2541(03)00234-1},

year  = {2003},

date = {2003-01-01},

journal = {Chemical Geology},

volume = {201},

pages = {161--179},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Singh_etal2003,

title = {Re-Os isotope systematics of sediments of the Brahmaputra River System: implications for their sources and for evolution of oceanic 187Os/188Os},

author = {S. Singh and L. Reisberg and C. France-Lanord},

doi = {10.1016/S0016-7037(00)00201-1},

year  = {2003},

date = {2003-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {67},

number = {21},

pages = {4101--4111},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ayalew_etal2002,

title = {Source, genesis and timing of giant ignimbrite deposits associated with Ethiopian continental flood basalts},

author = {D. Ayalew and P. Barbey and B. Marty and L. Reisberg and G. Yirgu and R. Pik},

doi = {10.1016/S0016-7037(01)00834-1},

year  = {2002},

date = {2002-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {66},

number = {8},

pages = {1429--1448},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ayalew_etal2002_2,

title = {Origin and timing of Ethiopian Ignimbrites},

author = {D. Ayalew and P. Barbey and B. Marty and L. Reisberg and G. Yirgu and R. Pik},

year  = {2002},

date = {2002-01-01},

journal = {Geological Journal},

volume = {36},

pages = {409--419},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dauphas_etal2002,

title = {Molybdenum nucleosynthetic dichotomy revealed in primitive meteorites},

author = {N. Dauphas and B. Marty and L. Reisberg},

doi = {10.1086/340580},

year  = {2002},

date = {2002-01-01},

journal = {Astrophysical Journal},

volume = {569},

pages = {L139-L142},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dauphas_etal2002_2,

title = {Inference on terrestrial genesis from molybdenum isotope systematics},

author = {N. Dauphas and B. Marty and L. Reisberg},

year  = {2002},

date = {2002-01-01},

journal = {Geophysical Research Letters},

volume = {29},

number = {6},

pages = {8-1},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dauphas_etal2002_3,

title = {Molybdenum evidence for inherited large scale isotope heterogeneity of the Protosolar Nebula},

author = {N. Dauphas and B. Marty and L. Reisberg},

doi = {10.1086/324597},

year  = {2002},

date = {2002-01-01},

journal = {The Astrophysical Journal},

volume = {565},

pages = {640--644},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dauphas_etal2002_4,

title = {An alternative explanation for the distribution of highly siderophile elements in Earth},

author = {N. Dauphas and L. Reisberg and B. Marty},

year  = {2002},

date = {2002-01-01},

journal = {Geochemical Journal},

volume = {36},

number = {4-5},

pages = {409--419},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Decitre_etal2002,

title = {Behavior of Li and its isotopes during serpentinization of oceanic peridotites},

author = {S. Decitre and E. Deloule and L. Reisberg and R. James and C. M\'{e}vel},

doi = {10.1029/2001GC000178},

year  = {2002},

date = {2002-01-01},

journal = {G-cubed},

volume = {3},

number = {1},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pierson-Wickmann_etal2002,

title = {Impure marbles of the Lesser Himalaya: another source of continental radiogenic osmium},

author = {A. -C. Pierson-Wickmann and L. Reisberg and C. France-Lanord},

doi = {10.1016/S0012-821X(02)00962-7},

year  = {2002},

date = {2002-01-01},

journal = {Earth and Planetary Science Letters},

volume = {204},

number = {1-2},

pages = {203--214},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pierson-Wickmann_etal2002_2,

title = {Behavior of Re and Os during low temperature alteration : results from Himalayan soils},

author = {A. -C. Pierson-Wickmann and L. Reisberg and C. France-Lanord},

doi = {10.1016/S0016-7037(01)00865-1},

year  = {2002},

date = {2002-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {66},

number = {9},

pages = {1539--1548},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reisberg+Meisel2002,

title = {The Re-Os isotopic system: a review of analytical techniques},

author = {L. Reisberg and T. Meisel},

doi = {10.1111/j.1751-908X.2002.tb00633.x},

year  = {2002},

date = {2002-01-01},

journal = {Geostandards Newsletter},

volume = {26},

number = {3},

pages = {249--267},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dauphas_etal2001,

title = {Solvent extraction, ion chromatography, and mass spectrometry of Molybdenum isotopes},

author = {N. Dauphas and L. Reisberg and B. Marty},

doi = {10.1021/ac000998g},

year  = {2001},

date = {2001-01-01},

journal = {Analytical Chemistry},

volume = {73},

pages = {2613--2616},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pierson-Wickmann_etal2001_2,

title = {Os-Sr-Nd results from sediments in the Bay of Bengal: implications for sediment transport and the marine Os record},

author = {A. -C. Pierson-Wickmann and L. Reisberg and C. France-Lanord and H. R. Kudrass},

doi = {10.1029/2000PA000532},

year  = {2001},

date = {2001-01-01},

journal = {Paleoceanography},

volume = {16},

number = {4},

pages = {435--444},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Peslier_etal2000,

title = {Re-Os constraints on harzburgite and lherzolite formation in the lithospheric mantle: a study of Northern Canadian Cordillera xenoliths},

author = {A. Peslier and L. Reisberg and J. Ludden and D. Francis},

doi = {10.1016/S0016-7037(00)00391-4},

year  = {2000},

date = {2000-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {64},

number = {17},

pages = {3061--3071},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Peslier_etal2000_2,

title = {Os isotopic systematics in mantle xenoliths: age constraints on the Canadian Cordilleran lithosphere},

author = {A. Peslier and L. Reisberg and J. N. Ludden and D. Francis},

doi = {10.1016/S0009-2541(99)00187-4},

year  = {2000},

date = {2000-01-01},

journal = {Chemical Geology},

volume = {166},

number = {1-2},

pages = {85--101},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pierson-Wickmann_etal2000,

title = {The Os isotopic composition of Himalayan river bedloads and bedrocks : importance of black shales},

author = {A. -C. Pierson-Wickmann and L. Reisberg and C. France-Lanord},

doi = {10.1016/S0012-821X(00)00003-0},

year  = {2000},

date = {2000-01-01},

journal = {Earth and Planetary Science Letters},

volume = {176},

pages = {203--218},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reisberg_etal1997,

title = {Os isotopic compositions of leachates and bulk sediments from the Bengal Fan},

author = {L. Reisberg and C. France-Lanord and A. -C. Pierson-Wickmann},

year  = {1997},

date = {1997-01-01},

journal = {Earth and Planetary Science Letters},

volume = {150},

pages = {117--127},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kumar_etal1996,

title = {A major and trace element and Sr, Nd, and Os isotopic study of a thick pyroxenite layer from the Beni Bousera Ultramafic Complex of N. Morocco},

author = {N. Kumar and L. Reisberg and A. Zindler},

doi = {10.1016/0016-7037(95)00443-2},

year  = {1996},

date = {1996-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {60},

pages = {1429--1444},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Molzahn_etal1996,

title = {Os, Sr, Nd, Pb, O isotope and trace element data from the Ferrar flood basalts, Antarctica : evidence for an enriched subcontinental lithospheric source},

author = {M. Molzahn and L. Reisberg and G. W\"{o}rner},

year  = {1996},

date = {1996-01-01},

journal = {Earth and Planetary Science Letters},

volume = {144},

pages = {529--546},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Brueckner_etal1995,

title = {A Pan African origin and uplift for the gneisses and peridotites of Zabargad Island, Red Sea : a Nd, Sr, Pb and Os isotope study},

author = {H. K. Brueckner and M. E. Elhaddad and B. Hamelin and S. Hemming and A. Kr\"{o}ner and L. Reisberg and M. Seyler},

year  = {1995},

date = {1995-01-01},

journal = {Journal of Geophysical Research},

volume = {100},

pages = {22283--22297},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reisberg+Lorand1995,

title = {Longevity of sub-continental mantle lithosphere from osmium isotope systematics in orogenic peridotite massifs},

author = {L. Reisberg and J. P. Lorand},

year  = {1995},

date = {1995-01-01},

journal = {Nature},

volume = {376},

pages = {159--162},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Snow+Reisberg1995,

title = {Os isotopic systematics of the MORB mantle : results from altered abyssal peridotites},

author = {J. E. Snow and L. Reisberg},

year  = {1995},

date = {1995-01-01},

journal = {Earth and Planetary Science Letters},

volume = {136},

pages = {723--733},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{LeMignot_etal,

title = {Re-Os geochronological evidence for multiple Paleoproterozoic gold events at the scale of the West African craton},

author = {E. Le Mignot and L. Reisberg and A. S. Andr\'{e}-Mayer and J. Miller and M. Ali Bouhifd},

journal = {Economic Geology},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{LeMignot_etal_2,

title = {The Paleoproterozoic copper-gold deposit of Gaoua, Burkina Faso: Evidence for a superimposition of a porphyry copper with an orogenic gold deposit},

author = {E. Le Mignot and L. Siebenaller and D. B\'{e}ziat and A. S. Andr\'{e}-Mayer and L. Reisberg and S. Salvi and G. Velasquez and C. Zimmermann and A. Nar\'{e}},

journal = {Economic Geology},

keywords = {},

pubstate = {published},

tppubtype = {article}

}