Catherine Zimmermann

@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{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{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{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{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{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{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{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{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{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}

}