Pierre-Henri Blard

@article{Charreau_etal2023,

title = {Unsteady topography in the eastern Tianshan due to imbalance between denudation and crustal thickening},

author = {J. Charreau and P. H. Blard and J. Lav\'{e} and S. Dominguez and W. S. Li},

doi = {10.1016/j.tecto.2022.229702},

year  = {2023},

date = {2023-01-01},

journal = {Tectonophysics},

volume = {848},

pages = {229702},

abstract = {The Tianshan mountains have complex and variable topography and documenting their growth is important for understanding both intracontinental mountain building and the evolution of the global climate. We investigate whether this topography is in equilibrium with crustal influx (thickening) and sediment outflux (denudation).Based on literature, we estimate that the eastern Tianshan has been subject to a total crustal shortening rate of textasciitilde9.4 mm/a across the Kuitun--Kuche transect, implying textasciitilde1.3 mm/a of crustal thickening and a total crustal influx of textasciitilde9 texttimes 107 m3/a. We measured in-situ cosmogenic 10Be concentrations in modern river sands of 34 catchments to constrain recent (0--6 ka) basin-averaged denudation rates within the range and on its two flanks. Denudation rates range from 0.020 textpm 0.002 to 0.53 textpm 0.07 mm/a, averaging 0.20 textpm 0.04 and 0.11 textpm 0.02 mm/a in the north and south, respectively; these rates correspond to respective total sediment outfluxes of (542 textpm 69) texttimes 104 and (164 textpm 24) texttimes 104 m3/a. To ensure that these values can be compared to Pleistocene tectonic rates, we reconstructed Pleistocene denudation rates in seven of the studied basins. For this, we determined inherited insitu cosmogenic 10Be concentrations from 11 cosmogenic depth profiles of abandoned fluvial terraces deposited in the Tianshan piedmonts. These data indicate that denudation rates have been relatively steady since the Pleistocene and thus that recent and Pleistocene sediment fluxes can be compared. These results show that crustal thickening outpaced denudation and sediment outflux by a factor of textasciitilde10. Therefore, the Tianshan topography is not in dynamic equilibrium and is growing, even if materials are being subducted into the mantle. Consequently, to sustain this disequilibrium, the range grew laterally. This lateral growth and the inheritance of structures and basins are likely responsible for the complex topography of the range.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blard_etal2023,

title = {Basal debris of the NEEM ice core, Greenland: a window into sub-ice-sheet geology, basal ice processes and ice-sheet oscillations},

author = {P. H. Blard and M. Protin and J. L. Tison and F. Fripiat and D. Dahl-Jensen and J. P. Steffensen and W. C. Mahaney and P. R. Bierman and A. J. Christ and L. B. Corbett and V. Debaille and T. Rigaudier and P. Claeys and ASTER Team.},

doi = {10.1017/jog.2022.122},

year  = {2023},

date = {2023-01-01},

journal = {Journal of Glaciology},

volume = {614},

pages = {1--19},

abstract = {We present new data from the debris-rich basal ice layers of the NEEM ice core (NW Greenland). Using mineralogical observations, SEM imagery, geochemical data from silicates (meteoric 10Be, $epsilon$Nd, 87Sr/86Sr) and organic material (C/N, $delta$13C), we characterize the source material, succession of previous glaciations and deglaciations and the paleoecological conditions during ice-free episodes. Meteoric 10Be data and grain features indicate that the ice sheet interacted with paleosols and eroded fresh bedrock, leading to mixing in these debris-rich ice layers. Our analysis also identifies four successive stages in NW Greenland: (1) initial preglacial conditions, (2) glacial advance 1, (3) glacial retreat and interglacial conditions and (4) glacial advance 2 (current ice-sheet development). C/N and $delta$13C data suggest that deglacial environments favored the development of tundra and taiga ecosystems. These two successive glacial fluctuations observed at NEEM are consistent with those identified from the Camp Century core basal sediments over the last 3 Ma. Further inland, GRIP and GISP2 summit sites have remained glaciated more continuously than the western margin, with less intense ice-substratum interactions than those observed at NEEM.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bekaert_etal2023,

title = {Last glacial maximum cooling of 9 textdegreeC in continental Europe from a 40 kyr-long noble gas paleothermometry record},

author = {D. V. Bekaert and P. H. Blard and Y. Raoult and R. Pik and R. Kipfer and A. M. Seltzer and E. Legrain and B. Marty},

doi = {10.1016/j.quascirev.2023.108123},

year  = {2023},

date = {2023-01-01},

journal = {Quaternary Science Reviews},

volume = {310},

pages = {108123},

abstract = {The Last Glacial Maximum (LGM; \^{a}`u26--18 kyr ago) is a time interval of great climatic interest characterized by substantial global cooling driven by radiative forcings and feedbacks associated with orbital changes, lower atmospheric CO2, and large ice sheets. However, reliable proxies of continental paleotemperatures are scarce and often qualitative, which has limited our understanding of the spatial structure of past climate changes. Here, we present a quantitative noble gas temperature (NGT) record of the last \^{a}`u40 kyr from the Albian aquifer in Eastern Paris Basin (France, \^{a}`u48textdegreeN). Our NGT data indicate that the mean annual surface temperature was \^{a}`u5 textdegreeC during the Marine Isotope Stage 3 (MIS3; \^{a}`u40--30 kyr ago), before cooling to \^{a}`u2 textdegreeC during the LGM, and warming to \^{a}`u11 textdegreeC in the Holocene, which closely matches modern ground surface temperatures in Eastern France. Combined with water stable isotope analyses, NGT data indicate $delta$D/NGT and $delta$18O/NGT transfer functions of +1.6 textpm 0.4texttenthousand/textdegreeC and +0.18 textpm 0.04texttenthousand/textdegreeC, respectively. Our noble-gas derived LGM cooling of \^{a}`u9 textdegreeC (relative to the Holocene) is consistent with previous studies of noble gas paleothermometry in European groundwaters but larger than the low-to-mid latitude estimate of 5.8 textpm 0.6 textdegreeC derived from a compilation of noble gas records, which supports the notion that continental LGM cooling was more extreme at higher latitudes. While an LGM cooling of \^{a}`u9 textdegreeC in Eastern France appears compatible with recent data assimilation studies, this value is greater than most estimates from current-generation climate model simulations of the LGM. Comparing our estimate for the temperature in Eastern France during MIS3 (6.4 textpm 0.5 textdegreeC) with GCM outputs presents a promising avenue to further evaluate climate model simulations and constrain European climate evolution over the last glacial cycle.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Seltzer_etal2023,

title = {Terrestrial amplification of past, present, and future climate change},

author = {A. M. Seltzer and P. H. Blard and S. C. Sherwood and M. Kageyama},

doi = {10.1126/sciadv.adf8119},

year  = {2023},

date = {2023-01-01},

journal = {Science Advances},

volume = {9},

number = {9},

pages = {eadf8119},

abstract = {Terrestrial amplification (TA) of land warming relative to oceans is apparent in recent climatic observations. TA results from land-sea coupling of moisture and heat and is therefore important for predicting future warming and water availability. However, the theoretical basis for TA has never been tested outside the short instrumental period, and the spatial pattern and amplitude of TA remain uncertain. Here, we investigate TA during the Last Glacial Maximum (LGM; textasciitilde20 thousand years) in the low latitudes, where the theory is most applicable. We find remarkable consistency between paleotemperature proxies, theory, and climate model simulations of both LGM and future climates. Paleoclimate data thus provide crucial new support for TA, refining the range of future lowlatitude, low-elevation TA to 1:37 +0:27 ?\u{I} 0:23 (95% confidence interval), i.e., land warming textasciitilde40% more than oceans. The observed data model theory agreement helps reconcile LGM marine and terrestrial paleotemperature proxies, with implications for equilibrium climate sensitivity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Charton_etal2022,

title = {New cosmogenic nuclide constraints on Late Glacial and Holocene glacier fluctuations in the sub-Antarctic Indian Ocean (Kerguelen Islands, 49-S)},

author = {J. Charton and I. Schimmelpfennig and V. Jomelli and G. Delpech and P. H. Blard and R. Braucher and D. Verfaille and V. Favier and V. Rinterknecht and H. Goosse and X. Crosta and L. Chassiot and L. Martin and D. Guillaume and C. Legentil},

doi = {10.1016/j.quascirev.2022.107461},

year  = {2022},

date = {2022-01-01},

journal = {Quaternary Science Review},

volume = {283},

pages = {107461},

abstract = {Cosmogenic nuclide dating of glacial landforms on the Kerguelen Archipelago (49-S, 69-E) gives the opportunity to study multi-millennial glacier fluctuations within the sub-Antarctic sector of the Indian Ocean. We here dated such geomorphic features to provide time constraints over the last 17,000 years using in situ-produced 36Cl in three glacial valleys : Val Travers valley, Ampere Glacier valley and Arago Glacier valley. For the first time, a combination of in situ-produced 36Cl and 10Be dating and 26Al/10Be ratios analysis was performed in the quartz-bearing syenite boulders of the Arago Glacier site. In addition, a Bayesian approach was computed to obtain a better constraint on moraine dating. Glacial advances occurred during the Late Glacial at 16.0 textpm 1.9 ka and at 12.9 textpm 1.7 ka in Val Travers, and at 13.6 textpm 1.8 ka in Arago Glacier valley, probably linked to the Heinrich Stadial 1 and/or Antarctic Cold Reversal events, respectively. This suggests that all glaciers at this latitude were broadly sensitive to the large-scale climatic signal of the Antarctic Cold Reversal. So far, no Early nor Mid-Holocene moraines have been found in the glacial valleys on Kerguelen, indicating that the glaciers had probably receded significantly during these periods. This is in agreement with previously determined 14C ages from peat bogs, which suggest extensive deglaciation during several millennia of the Holocene period. Samples from glacially-polished bedrock surfaces (ranging from 4.4 ka to 14 ka) at Ampere Glacier site also suggest that this valley was ice free for several millennia during the Holocene. Finally, glaciers seem to have re-advanced only during the Late Holocene, especially within the last millennium, at 1 ka, 430 yr and 300 yr. A comparison of this new dataset with the available 10Be ages from other southern midlatitude regions during the Holocene allows the identification of three different glacier evolution patterns. We suspect that variations of Kerguelen glaciers, which are located in the Southern Indian Ocean, were controlled by the combined effects of sea surface temperature related to the variations of the Antarctic Polar Front and fluctuations of precipitation related to long-term variations of the Southern Annular Mode.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Defourny_etal2022,

title = {CO2/3He ratios reveal the presence of mantle gas in the CO2-rich groundwaters of the Ardenne massif (Spa, Belgium)},

author = {A. Defourny and P. H. Blard and L. Zimmermann and P. Job\'{e} and A. Collignon and F. Nguyen and A. Dassargues},

doi = {10.5194/hess-2021-611},

year  = {2022},

date = {2022-01-01},

journal = {Hydrology and Earth Systems Science},

abstract = {Natural CO2-rich groundwaters of eastern Belgium have been known for centuries although the exact origin of the gas they contained was still unclear. This paper presents the results of a sampling campaign in the area (Spa, Stoumont, Malmedy) where 30 samples of both carbogazeous and non-carbogazeous groundwaters have been analyzed for major elements, CO2 content and carbon isotopic composition. Among them, 13 samples were analyzed for 3He/4He and 4He/20Ne ratios. The combination of $delta$13C and 3He/CO2 ratios have 5 shown with a high level of confidence that the CO2 in groundwater from springs and boreholes has a mantellic origin, and can very likely be attributed to the degassing of the neighboring and still buoyant Eifel mantle plume, located at a distance of 100 km eastwards. The identity and nature of the deep-rooted fractures that act as CO2 transport pathway to the surface are still to be clarified, but several major thrust faults exist in the Rhenish Massif and could connect the Eifel volcanic field with the studied area.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jomelli_etal2022,

title = {In-phase millennial-scale glacier changes in the tropics and North Atlantic regions during the Holocene},

author = {V. Jomelli and D. Swingedouw and M. Vuille and V. Favier and B. Goehring and J. Shakun and R. Braucher and I. Schimmelpfennig and L. Menviel and A. Rabatel and L. C. P. Martin and P. H. Blard and T. Condom and M. Lupker and M. Christl and D. Verfaillie and A. Gorin and G. Auma^itre and D. Bourl`es and K. douche Keddadouche},

doi = {https://doi.or10.1038/s41467-022-28939-9},

year  = {2022},

date = {2022-01-01},

journal = {Nature Communications},

volume = {13},

number = {1419},

abstract = {Based on new and published cosmic-ray exposure chronologies, we show that glacier extent in the tropical Andes and the north Atlantic regions (TANAR) varied in-phase on millennial timescales during the Holocene, distinct from other regions. Glaciers experienced an early Holocene maximum extent, followed by a strong mid-Holocene retreat and a re-advance in the late Holocene. We further explore the potential forcing of TANAR glacier variations using transient climate simulations. Since the Atlantic Meridional Overturning Circulation (AMOC) evolution is poorly represented in these transient simulations, we develop a semi-empirical model to estimate the ‘‘AMOC-corrected’’ temperature and precipitation footprint at regional scales. We show that variations in the AMOC strength during the Holocene are consistent with the observed glacier changes. Our findings highlight the need to better constrain past AMOC behavior, as it may be an important driver of TANAR glacier variations during the Holocene, superimposed on other forcing mechanisms.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Legrain_etal2022,

title = {Glacial equilibrium line--based relationship for paleoclimate reconstructions (Sierra Nevada, USA)},

author = {E. Legrain and P. H. Blard and J. Charreau},

doi = {10.1017/qua.2022.10},

year  = {2022},

date = {2022-01-01},

journal = {Quaternary Research},

pages = {1--12},

abstract = {We use PRISM climatic data (1981--2010) and Landsat images (2012--2013) to establish an empirical relationship linking annual temperature and precipitation to the equilibrium line altitude (ELA) of glaciers in the Sierra Nevada (36--41textdegreeN, California, USA). For this, we determined the present-day ELAs of 57 glaciers and the local 0textdegreeC isotherms elevation Iso0, averaged over the 1981--2010 period. The difference, for each glacier, is Y, the normalized snowline altitude (Y=ELA -- Iso0). We then empirically calibrated a logarithmic relationship between this normalized snowline altitude and mean annual precipitation using data from partially covered glaciers. Our calibration is statistically distinct from that previously established for the tropical and midlatitude Andes (Fox and Bloom [1994], Journal of Geography (Chigaku Zasshi), 103, 867--885 ; Condom et al. [2007], Global and Planetary Change, 59, 189--202). This new relationship for North America is an easy-to-use tool to permit paleoclimatic reconstructions from paleo-ELAs. For a specific paleoglacial site, paleotemperature can be computed knowing the paleoprecipitation range, and vice versa.We also performed a test showing that, if precipitation is well known, the uncertainty associated with paleotemperature is about 1textdegreeC (1$sigma$).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zerathe_etal2022,

title = {Cosmogenic 3He and 10Be denudation rates in the Central Andes: Comparison with a natural sediment trap over the last 18 ka},

author = {S. Zerathe and C. Litty and P. H. Blard and F. Delgado and L. Audin and J. Carcaillet and ASTER Team.},

doi = {https://doi.org/10.1016/j.epsl.2022.117869},

year  = {2022},

date = {2022-01-01},

journal = {Earth and Planetary Science Letters},

volume = {599},

pages = {117869},

abstract = {It is of major importance for Earth surface sciences to reconstruct denudation rates in the most precise and accurate way. For this, it can be useful to test on the same setting methods based on different assumptions, such as those relying on geomorphological and geochemical observations. Here, we use an exceptionally suited setting in the Locumba catchment (southwestern Peruvian Andes) that offers the unique opportunity to compare denudation rates derived from in situ cosmogenic 3He and 10Be with a geomorphological sediment budget integrated over the last 18 ka. The sediment budget is estimated by determining the volume of sediment trapped in the Aricota lake that formed 18 ka ago after the occurrence of a giant rockslide dam. We reconstructed the topography of the Locumba valley before the dam emplacement and established that the captured sediment volume is 0.8 textpm 0.1 km3. Considering that the lake-water output is restricted to seepage through the dam and that overflow above the dam never occurred, this volume correctly represents the sediment flux integrated over the last 18 ka. Integrating this volume over the upstream catchment area (\^{a}`u1500 km2), we derived a corresponding mean erosion rate of 30 textpm 9 mm.ka\^{a}ˆ’1. Fluvial sediments feeding the Aricota lake were sampled to derive denudation rates from in-situ cosmogenic 10Be in the silicates and from in-situ cosmogenic 3He in the ferromagnesian minerals. Cosmogenic nuclide denudation rates from the main stream are 30 textpm 2, 33 textpm 2, 21 textpm 1 and 82 textpm 5 mm.ka\^{a}ˆ’1 for the 10Be-quartz, the 10Be-feldspar, the 3He-amphibole and 3He-pyroxene, respectively. The consistency between the cosmogenic nuclide denudation rates derived from 10Be in the silicates and the erosion rate derived from our sediment budget shows that the 10Be accurately estimates of the sediment flux. Additionally, this work provides the first successful application of 10Be-feldspar nuclide-mineral pair to derive catchment-mean denudation rate and demonstrate that 10Be-feldspar can thus be a good alternative in catchments dominated by volcanic rocks with no quartz. The discrepancies observed between the denudation rates derived from the 3He-amphibole and 3He-pyroxene couples require further studies.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Capelle_etal2021,

title = {Discriminating value of HR-pQCT for fractures in women with similar FRAX scores: A substudy of the FRISBEE cohort},

author = {S. I. Capelle and M. Moreau and R. Karmali and L. Iconaru and F. Baleanu and V. Kinnard and M. Paesmans and S. Rozenberg and M. Rubinstein and M. Surquin and P. H. Blard and R. Chapurlat and J. J. Body and P. Bergmann},

doi = {10.1016/j.bone.2020.115613},

year  = {2021},

date = {2021-01-01},

journal = {Bone},

abstract = {Areal bone mineral density (aBMD) has a low sensitivity to identify women at high fracture risk. The FRAX algorithm, by combining several clinical risk factors, might improve fracture prediction compared to aBMD alone. Several micro-architectural and biomechanical parameters which can be measured by high-resolution peripheral quantitative computed tomography (HR-pQCT) are associated with fracture risk. HR-pQCT in com- bination or not with finite element analysis (FEA) may be used to improve bone strength prediction.Our aim was to assess whether HR-pQCT measurements (densities, cortical and trabecular microarchitecture, biomechanical proprieties assessed by FEA) had an added value in predicting fractures in a subgroup of women belonging to the Belgian FRISBEE cohort. One hundred nineteen women who sustained a fracture (aged 60 to 85 years) during the initial follow-up of our cohort had a radius and tibia examination by HR-pQCT and were compared with controls matched for their FRAX score at baseline. We found that low distal radius total (OR = 1.41 [1.07--1.86] per SD, p \< 0.05) and trabecular densities (OR = 1.45 [1.10--1.90], p \< 0.01), trabecular number (OR = 1.32 [1.01--1.72], p \< 0.05), intra individual distribution of separation (OR = 0.73 [0.54--0.99], p \< 0.05) as several FEA parameters were significantly associated with fractures. At the distal tibia, impaired cortical density (OR = 1.32 [1.03--1.70] per SD, p \< 0.05) and thickness (OR = 1.29 [1.01--1.63], p \< 0.05) and apparent modulus (OR = 1.30 [1.01--1.66], p \< 0.05) were significantly corre- lated with fractures. A low ultra distal radial aBMD (UDR) measured at the time of HR-pQCT was significantly associated with fractures (OR = 1.67 [1.22--2.28], p \< 0.01). Women from both groups were followed further after the realization of the HR-pQCT and 46 new fractures were registered. In this second part of the study, low UDR aBMD (OR = 1.66 [1.18--2.35], p \< 0.01), total (OR = 1.48 [1.08--2.03], p \< 0.05), cortical (OR = 1.40 [1.04--1.87], p \< 0.05) and trabecular (OR = 1.37 [1.01--1.85], p \< 0.05) densities or apparent modulus (OR = 1.49 [1.07--2.05], p \< 0.05) at the radius were associated with a significant increase of fracture risk. At the tibia, only the cortical density was significantly associated with the fracture risk (OR = 1.34 [1.02--2.76], p \< 0.05). These results confirm the interest of HR-pQCT measurements for the evaluation of fracture risk, also in women matched for their baseline FRAX score. They also highlight that UDR aBMD contains pertinent in- formation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hemelsdal_etal2021,

title = {Tectono-climatic controls of the early rift alluvial succession: Plio-Pleistocene Corinth Rift (Greece)},

author = {R. Hemelsda"el and J. Charreau and M. Ford and M. S. Proborukmi and F. Malartre and B. Urban and P. H. Blard},

doi = {10.1016/j.palaeo.2021.110507},

year  = {2021},

date = {2021-01-01},

journal = {Palaeogeography, Palaeoclimatology, Palaeoecology},

volume = {576},

pages = {110507},

abstract = {Proximal alluvial sediments represent a useful sedimentary archive to reconstruct the tectono-climatic history of continental rift basins. However, poor dating of coarse fluvial successions usually prevents high-resolution distinction of tectonic and climatic processes, and thus good determination of process rates. This paper presents a dating study of Plio-Pleistocene Kalavryta river system during the early history of the Corinth Rift (northern Peloponnese, Greece) based on magnetostratigraphy and palynology. This river system developed across several active normal fault blocks that are now uplifted along the southern rift margin. The detailed sedimentary record constrains alluvial architectures from the proximal basin to the river outlet where small deltas built into a shallow lake. In four magnetostratigraphy sections the correlation to the reference scale relies on the identification of the Gauss/Matuyama magnetic reversal and biostratigraphic elements. The river system developed between about 3.6 to 1.8 Ma, with sediment accumulation rates (SARs) ranging from 0.40 to 0.75 mm yr−1. SAR is lower in the alluvial fans than in the deltaic system, and higher at the centre of the normal fault depocentres than at the fault tip. By comparison with worldwide Cenozoic SARs, our values are higher but lie in the same range as those determined in coarse alluvial foreland basins. Moreover, in the context of overfilled intra-mountainous rift basins, these rates are minimum values and can be used as a proxy for accommodation rate. Therefore, early rift stratal wedges and growth synclines attest high sedimentation rates and also high rates of tectonic processes. Finally, in the distal river system, floral compositions and changes of vegetation deduced from palynological data are coherent with alternating fluvio-deltaic and shallow lacustrine deposits, which are linked to relative base level variations. Dry/cool climate is preferentially recorded during periods of low lake level, while the warm/moist climate is mainly recorded in prodelta deposits during periods of high lake level. This correlation suggests that, despite the dominant control of active faulting, climate is a key control of syn-rift stratigraphic architectures.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mariotti_etal2021,

title = {Nonlinear forcing of climate on mountain denudation during glaciations},

author = {A. Mariotti and P. H. Blard and J. Charreau and S. Toucanne and S. J. Jorry and S. Molliex and D. L. Bourl`es and G. Auma^itre and K. Keddadouche},

doi = {10.1038/s41561-020-00672-2},

year  = {2021},

date = {2021-01-01},

journal = {Nature Geoscience},

volume = {14},

pages = {16--22},

abstract = {Denudation is one of the main processes that shapes landscapes. Because temperature, precipitation and glacial extents are key factors involved in denudation, climatic fluctuations are thought to exert a strong control on this parameter over geological timescales. However, the direct impacts of climatic variations on denudation remain controversial, particularly those involving the Quaternary glacial cycles in mountain environments. Here we measure in situ cosmogenic 10Be concentration in quartz in marine turbidites of two high-resolution cores collected in the Mediterranean Sea, providing a near-continuous (temporal resolution of 1--2thinspacekyr) reconstruction of denudation in the Southern Alps since 75thinspacekyr ago (ka). This high-resolution palaeo-denudation record can be compared with well-constrained climatic variations over the last glacial cycle. Our results indicate that total denudation rates were approximately two times higher than present during the Last Glacial Maximum (26.5--19thinspaceka), the glacial component of the denudation rates being 1.5+0.9−1.0thinspacemmthinspaceyr−1. However, during moderately glaciated times (74--29thinspaceka), denudation rates were similar to those today (0.24thinspacetextpmthinspace0.04thinspacemmthinspaceyr−1). This suggests a nonlinear forcing of climate on denudation, mainly controlled by the interplay between glacier velocity and basin topography. Hence, the onset of Quaternary glaciations, 2.6 million years ago, did not necessarily induce a synchronous global denudation pulse.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Molliex_etal2021,

title = {Quaternary evolution of the Golo river alluvial plain (NE Corsica, France)},

author = {S. Molliex and G. Jouet and P. H. Blard and J. Moreau and J. Storms Demartini and C. Vella and Aster Team.},

doi = {10.1016/j.quageo.2020.101115},

year  = {2021},

date = {2021-01-01},

journal = {Quaternary Geochronology},

volume = {61},

pages = {101115},

abstract = {The Golo River drains a steep catchment (average gradient of 30 m km−1, surface of 1214 km2) in the northeast part of Corsica Island, delivering sediments to the Ligurian Sea. In this study, we review and revise the geologic map and constrain the extent of the Golo coastal alluvial plain formations and their relative and absolute chronology. To update the surface extent of each formation, we performed a geomorphologic analysis with DEMs and satellite imagery data coupled with an extensive pedogenic and sedimentary field observations database, including a new borehole of 117,4 m depth. Additionally, we performed in-situ cosmogenic 10Be analysis from a depth-profile in the well-preserved alluvial terrace Fy2, yielding a minimum age of 70 ka for its emplacement. Our new chronology, based on cosmogenic 10Be and soil chronosequences, implies older ages than those previously obtained with luminescence methods. Soil mixing by bioturbation is proposed as a possibility to explain differences between luminescence and 10Be ages. In this scenario, 10Be dates the original deposition of the alluvial terrace, while luminescence dates a later soil development. We highlighted at least five outcropping alluvial terraces in the Golo coastal plain, which are controlled by sea-level fluctuations and were most likely deposited during past sea-level highstands (close to present-day sea-level). Moreover, we identified from a borehole more than 117 m of coarse fluvial sediments in the plain, that do not outcrop at the surface. New cosmogenic 26Al/10Be burial ages suggest that this sedimentary unit results from a thick accumulation of fluvial material filling a zone significantly affected by subsidence, probably accommodated by a normal fault during the Early Quaternary.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Christ_etal2021,

title = {A multimillion-year-old record of Greenland vegetation and glacial history preserved in sediment beneath 1.4 km of ice at Camp Century},

author = {A. J. Christ and P. R. Bierman and J. M. Schaefer and D. Dahl-Jensen and J. P. Steffensen and L. B. Corbett and D. M. Peteet and E. K. Thomas and E. J. Steig and T. M. Rittenour and J. L. Tison and P. H. and Blard},

doi = {10.1073/pnas.2021442118},

year  = {2021},

date = {2021-01-01},

journal = {PNAS},

volume = {118},

number = {13},

pages = {e-2021442118},

abstract = {Understanding the history of the Greenland Ice Sheet (GrIS) is critical for determining its sensitivity to warming and contribution to sea level; however, that history is poorly known before the last interglacial. Most knowledge comes from interpretation of marine sediment, an indirect record of past ice-sheet extent and behavior. Subglacial sediment and rock, retrieved at the base of ice cores, provide terrestrial evidence for GrIS behavior during the Pleistocene. Here, we use multiple methods to determine GrIS history from subglacial sediment at the base of the Camp Century ice core collected in 1966. This material contains a stratigraphic record of glaciation and vegetation in northwestern Greenland spanning the Pleistocene. Enriched stable isotopes of pore-ice suggest precipitation at lower elevations implying ice-sheet absence. Plant macrofossils and biomarkers in the sediment indicate that paleo-ecosystems from previous interglacial periods are preserved beneath the GrIS. Cosmogenic 26Al/10Be and luminescence data bracket the burial of the lower-most sediment between \<3.2 textpm 0.4 Ma and \>0.7 to 1.4 Ma. In the upper-most sediment, cosmogenic 26Al/10Be data require exposure within the last 1.0 textpm 0.1 My. The unique subglacial sedimentary record from Camp Century documents at least two episodes of ice-free, vegetated conditions, each followed by glaciation. The lower sediment derives from an Early Pleistocene GrIS advance. 26Al/10Be ratios in the upper-most sediment match those in subglacial bedrock from central Greenland, suggesting similar ice-cover histories across the GrIS. We conclude that the GrIS persisted through much of the Pleistocene but melted and reformed at least once since 1.1 Ma.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blahut_etal2020,

title = {Volcanic edifice slip events recorded on the fault plane of the San Andr\'{e}s Landslide, El Hierro, Canary Islands},

author = {J. Blahut and I. Mitrovic-Woodell and I. Baron and M. Ren\'{e} and M. Rowberry and P. H. Blard and F. Balek Hartvich and S. Meletlidis},

doi = {10.1016/j.tecto.2019.228317},

year  = {2020},

date = {2020-01-01},

journal = {Tectonophysics},

volume = {776},

pages = {228317},

abstract = {Volcanic flank collapses often result in giant debris avalanches that are capable of travelling tens of kilometres across the ocean floor and generating tsunamis that devastate distant communities. The San Andr\'{e}s Landslide on El Hierro, Canary Islands, represents one of the few places in the world where it is possible to investigate the landslide mass and fault planes of a volcanic collapse structure. In this study, a new conceptual model for the development of this enormous slump is presented on the basis of structural geological and geomorphological measurements, petrological and microstructural analyses, and cosmogenic radionuclide dating. Structural geological and geomorphological measurements indicate that the fault plane records two distinct events. Petrological and microstructural analyses demonstrate that a thin layer of frictionite covers the surface of the fault in contact with an oxidised tectonic breccia that transitions into the underlying undeformed basanite host rock. This frictionite comprises a heterogeneous cataclastic layer and a translucent silica layer that are interpreted to represent two separate slip events on the basis of their architecture and crosscutting relationships. Cosmogenic 3He dating reveals a maximum exposure age of 183 textpm 17 ka to 52 textpm 17 ka. Arguments are presented in support of the idea that the first slip event took place between 545 ka and 430 ka, prior to significant clockwise rotation of El Hierro, and the second slip event took place between 183 ka and 52 ka, perhaps in association with one of the giant debris avalanches that occurred around that time. This is the first time that more than one slip event has been recognised from the fault plane of the San Andr\'{e}s Landslide. It is also believed to be the first time a silica layer resulting from frictional melt has been described in a volcanic setting.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Charreau_etal2020,

title = {A 6 Ma record of palaeodenudation in the central Himalayas from in situ cosmogenic 10 Be in the Surai section},

author = {J. Charreau and J. Lav\'{e} and C. France-Lanord and N. Puchol and P. H. Blard and R. Pik and A. P. Gajurel and ASTER Team.},

doi = {10.1111/bre.12511},

year  = {2020},

date = {2020-01-01},

journal = {Basin Research},

pages = {1--22},

abstract = {To better constrain late Neogene denudation of the Himalayas, we analysed in situ 10Be concentrations in 17 Neogene sediment samples of the Surai section (central Nepal) and two modern sediment samples of the Rapti River. We first refined the depositional ages of the Surai section from 36 new paleomagnetic analyses, five 26Al/10Be burial ages, and, based on the Dynamic Time Warping algorithm, 104 automatically calculated likely magnetostratigraphic correlations. We also traced changing sediment sources using major element and Sr-Nd isotopic data, finding at 4--3Ma a switch from a large, trans-Himalayan river to a river draining only the Lesser Himalaya and Siwalik piedmont, increasing the contribution of recycled sediments at that time. 10Be concentrations in Neogene sediments range from (1.00 textpm0.36) to (5.22textpm0.98)texttimes103 at g--1 and decrease with stratigraphic age. Based on a flood plain transport model, our refined age model, and assuming a drainage change at 4--3Ma, we reconstructed 10Be concentrations at the time of deposition. Assuming cosmogenic production rates similar to those of the modern basins, we calculated palaeodenudation rates of 0.9textpm0.5 to 3.9textpm2.7mm a --1 from ca. 6 to 3Ma in the palaeo-Karnali basin and 0.6textpm0.2 to 1.6textpm0.8mm a --1 since ca. 3Ma in the palaeo-Rapti basin. Given the uncertainties and similar modern values of 2mm a--1, the palaeo-Karnali denudation rates may have been steady at 1.7textpm0.3mm a--1 for the last ca. 6Ma. A transient acceleration of the denudation in the palaeo-Rapti basin of 1.5mm a--1 since ca. 1.5Ma was likely due to the reworking of older, 10Be-depleted Siwalik sediments in the foreland. If true, this steadiness of the denudation rates may suggest that Quaternary glaciations did not largely affect Himalayan denudation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Charreau_etal2020_2,

title = {Late Miocene to Quaternary slip history across the Qiulitag anticline in the southern Tianshan piedmont},

author = {J. Charreau and A. Sart\'{e}gou and D. Saint-Carlier and J. Lav\'{e} and P. H. Blard and S. Dominguez and S. Li Wang and G. Rao and ASTER Team.},

doi = {10.1111/ter.12439},

year  = {2020},

date = {2020-01-01},

journal = {Terra Nova},

volume = {32},

pages = {89--96},

abstract = {In this study, we reconstruct the Miocene to Quaternary shortening history acrossthe Qiulitag anticline, a complex fault-bend fold located in southern Tianshan. Westudied the Yaha and Kuche sections, where we combined surface structural measurements and seismic imaging to model the stratigraphic horizons. The history of folding was reconstructed based on magnetostratigraphic analyses and eight cosmogenic burial ages in Kuche. Pleistocene deformation rates were also quantifiedin Yaha based on a deformed fluvial terrace that we dated to textasciitilde67 ka using a cosmogenic depth profile. Our results suggest that the fold grew at a mean slip rate of 0.9--1.3 mm/a in both sections but accelerated to textasciitilde2.5 mm/a during the Pleistocene in Kuche. These results support a migration of the deformation towards the basin during the Pleistocene and suggest that most of the present deformation in the Tianshan is accommodated across the external structures of the range.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Litty_etal2020,

title = {Spatial variability of Quaternary denudation rates across a volcanic ocean island (Santo Ant~ao, Cape Verde) from cosmogenic 3He},

author = {C. Litty and J. Charreau and P. H. Blard and R. Pik and S. Nomade},

doi = {10.1016/j.geomorph.2020.107557},

year  = {2020},

date = {2020-01-01},

journal = {Geomorphology},

volume = {375},

pages = {107557},

abstract = {Denudation of volcanic ocean islands creates remarkable landscapes and contributes to Earthtextquoterights carbon cycle, since the chemical alteration of basalts is a CO2 sink. Because many volcanic islands have large climate gradients and relatively lowvariations in lithology and tectonic history, they represent excellent natural laboratories for studying climatic effects on landscape evolution. However, little is known about the control of denudation rates in ocean islands and the respective influences of climatic gradients andmorphological parameters. Here,we present new measurements of long-term denudation rates from Santo Ant~ao Island, Cape Verde (17textdegreeN). In this 779 km2 island, mean annual precipitation ranges from 40 mmtextperiodcenteredyr−1 in the southwest to 1100 mmtextperiodcenteredyr−1 in the north. To constrain the spatial distribution of denudation rates, we measured the cosmogenic 3He concentration in river transported pyroxene grains from 23 river bedload samples. We obtained basin wide denudation rates ranging from 2.7textpm0.1 to 57.5textpm0.3 m/Ma. The denudation rates display a significant spatial variability, with the highest rates in catchments located in the northeast side of the island where modern precipitation are the highest and lowdenudation rates in the southern andwestern dry basins. Our study shows that precipitation is themain control on denudation and landscape development of the Santo Ant~ao volcanic island. This study provides for the first time the spatial distribution of denudation rates across a volcanic island located in a tropical zone.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Martin_etal2020,

title = {Antarctic-like temperature variations in the Tropical Andes recorded by glaciers and lakes during the last deglaciation},

author = {L. C. P. Martin and P. H. Blard and J. Lav\'{e} and V. Jomelli and J. Charreau and T. Condom and M. Lupker},

doi = {10.1016/j.quascirev.2020.106542},

year  = {2020},

date = {2020-01-01},

journal = {Quaternary Science Reviews},

volume = {247},

pages = {106542},

abstract = {The respective impacts of Northern and Southern Hemispheric climatic changes on the Tropics during the last deglaciation remain poorly understood. In the High Tropical Andes, the Antarctic Cold Reversal (ACR, 14.3--12.9 ka BP) is better represented among morainic records than the Younger Dryas (12.9--11.7 ka BP). However, in the Altiplano basin (Bolivia), two cold periods of the Northern Hemisphere (Heinrich Stadial 1a, 16.5--14.5 ka BP, and the Younger Dryas) are synchronous with (i) major advances or standstills of paleoglaciers and (ii) the highstands of giant paleolakes Tauca and Coipasa.Here, we present new cosmic ray exposure (CRE) ages from glacial landforms of the Bolivian Andes that formed during the last deglaciation (Termination 1). We reconstruct the equilibrium line altitudes (ELA) associated with each moraine and use them in an inverse algorithm combining paleoglaciers and paleolake budgets to derive temperature and precipitation during the last deglaciation.Our temperature reconstruction ($Delta$T relative to present day) yields a consistent regional trend of progressive warming from $Delta$T = −5 to −2.5 textdegreeC during 17--14.5 ka BP, followed by a return to colder conditions around −4 textdegreeC during the ACR (14.5--12.9 ka BP). The Coipasa highstand (12.9--11.8 ka BP) is coeval with another warming trend followed by $Delta$T stabilization at the onset of the Holocene (ca. 10 ka BP), around −3 textdegreeC. Our results suggest that, during the last deglaciation (20--10 ka BP) atmospheric temperatures in the Tropical Andes mimicked Antarctic variability, whereas precipitation over the Altiplano was driven by changes in the Northern Hemisphere.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Sartgou_etal2020,

title = {Late Cenozoic evolution of the Ari`ege River valley (Pyrenees) constrained by cosmogenic 26Al/10Be and 10Be/21Ne dating of cave sediments},

author = {A. Sart\'{e}gou and P. H. Blard and R. Braucher and D. L. Bourl`es and P. Sorriaux and L. Zimmermann and A. Laffitte and B. Tibari and L. Leanni and V. Guillou and A. Bourdet and ASTER team.},

doi = {10.1016/j.geomorph.2020.107441},

year  = {2020},

date = {2020-01-01},

journal = {Geomorphology},

volume = {371},

pages = {107441},

abstract = {Despite increasing knowledge on the orogenic phases of the Pyrenees, the Neogene evolution of the range remains poorly constrained. The central Pyrenees, particularly the Ari`ege River valley and its terrace systems and glacial extensions, are key to reconstructing Pyrenean evolution during the Neogene. However, fewterrace relics remain on the piedmont edges. To overcome this limitation and temporally extend the dataset obtained fromterraces, we focus on alluvium-filled horizontal epiphreatic passages developed in limestone karstic networks. These landforms record the transient position of former local base levels during the process of valley deepening, similar to fluvial terraces. The alluviumfills of the studied caves in the Tarascon-sur-Ari`ege area, in the transition zone between the upper range and the piedmont, therefore enable the reconstruction of the geodynamic evolution of the Ari`ege River valley. All studied caves are developed on at least eight levels. Based on burial durations determined by 26Al/10Be and 10Be/21Ne terrestrial cosmogenic nuclide dating of samples from epiphreatic levels, our results indicate Langhian to Messinian ( 13--5 Ma) incision rates averaging 48 m Myr−1. However, the obtained record does not allow us to accurately retrace the Pliocene evolution of the area due to the lack of known caves at corresponding levels. Moreover, raised local base levels during glacial phases both make the record more complex and call into question the methodological approach in terms of potential internal sediment remobilization and mixing related to implied re-flooding periods.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Palacios_etal2020,

title = {The deglaciation of the Americas during the Last Glacial Termination},

author = {D. Palacios and C. R. Stokes and F. M. Philipps and J. J. Clague and J. Alcala-Reygosa and N. Andres and I. Angel and P. H. and Blard},

doi = {10.1016/j.earscirev.2020.103113},

year  = {2020},

date = {2020-01-01},

journal = {Earth-Science Reviews},

volume = {203},

abstract = {This paper reviews current understanding of deglaciation in North, Central and South America from the Last Glacial Maximum to the beginning of the Holocene. Together with paleoclimatic and paleoceanographic data, we compare and contrast the pace of deglaciation and the response of glaciers to major climate events. During the Global Last Glacial Maximum (GLGM, 26.5-19 ka), average temperatures decreased 4textdegree to 8textdegreeC in the Americas, but precipitation varied strongly throughout this large region. Many glaciers in North and Central America achieved their maximum extent during the GLGM, whereas others advanced even farther during the subsequent Heinrich Stadial 1 (HS-1). Glaciers in the Andes also expanded during the GLGM, but that advance was not the largest, except on Tierra del Fuego. HS-1 (17.5-14.6 ka) was a time of general glacier thickening and advance throughout most of North and Central America, and in the tropical Andes; however, glaciers in the temperate and subpolar Andes thinned and retreated during this period. During the B\olling-Aller\od interstadial (B-A, 14.6-12.9 ka), glaciers retreated throughout North and Central America and, in some cases, completely disappeared. Many glaciers advanced during the Antarctic Cold Reversal (ACR, 14.6-12.9 ka) in the tropical Andes and Patagonia. There were small advances of glaciers in North America, Central America and in northern South America (Venezuela) during the Younger Dryas (12.9-11.7 ka), but glaciers in central and southern South America retreated during this period, except on the Altiplano where advances were driven by an increase in precipitation. Taken together, we suggest that there was a climate compensation effect, or textquoteleftseesawtextquoteright, between the hemispheres, which affected not only marine currents and atmospheric circulation, but also the behavior of glaciers. This seesaw is consistent with the opposing behavior of many glaciers in the Northern and Southern Hemispheres.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Balco_etal2019,

title = {Cosmogenic and nucleogenic 21Ne in quartz in a 28-meter sandstone core from the McMurdo Dry Valleys, Antarctica},

author = {G. Balco and P. H. Blard and D. L. Shuster and J. O. H. Stone and L. Zimmermann},

doi = {10.1016/j.quageo.2019.02.006},

year  = {2019},

date = {2019-01-01},

journal = {Quaternary Geochronology},

volume = {52},

pages = {63--76},

abstract = {We measured concentrations of Ne isotopes in quartz in a 27.6-m sandstone core from a low-erosion-rate site at 2183m elevation at Beacon Heights in the Antarctic Dry Valleys. Surface concentrations of cosmogenic 21Ne indicate a surface exposure age of at least 4.1 Ma and an erosion rate no higher than ca. 14 cm Myr−1 21Ne concentrations in the upper few centimeters of the core show evidence for secondary spallogenic neutron escape effects at the rock surface, which is predicted by first-principles models of cosmogenic-nuclide production but isnot commonly observed in natural examples. We used a model for 21Ne production by various mechanisms fit to the observations to distinguish cosmic-ray-produced 21Ne from nucleogenic 21Ne produced by decay of trace U and Th present in quartz, and also constrain rates of subsurface 21Ne production by cosmic-ray muons. Core samples have a quartz (U-Th)/Ne closure age, reflecting cooling below approximately 95 textdegreeC, near 160 Ma, which is consistent with existing apatite fission-track data and the 183 Ma emplacement of nearby Ferrar dolerite intrusions. Constraints on 21Ne production by muons derived from model fitting are consistent with a previously proposed value of 0.79 mb at 190 GeV for the cross-section for 21Ne production by fast muon interactions, but indicate that 21Ne production by negative muon capture is likely negligible.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blard_etal2019,

title = {Paired-cosmogenic nuclide paleoaltimetry},

author = {P. H. Blard and M. Lupker and M. Rousseau},

doi = {10.1016/j.epsl.2019.03.005},

year  = {2019},

date = {2019-01-01},

journal = {Earth and Planetary Science Letters},

volume = {515},

pages = {271--282},

abstract = {Goal -- The reconstruction of past topographies remains challenging and only a few methods allow accurate determination of past surface elevations. We propose here a new technique for deriving paleo-elevations, in which multiple cosmogenic nuclides are measured in the same geological sample exposed at the Earthtextquoterights surface. This method relies on the altitude dependence of the cosmogenic nuclidestextquoteright production rates combined with the radioactive decays of nuclides with different half-lives.Theory -- The position of the two cosmogenic nuclide exposure curves (26Al/10Be vs 10Be or 10Be/21Ne vs 10Be) depends on the altitude of exposure. If the studied surfaces have been exposed for sufficiently long durations (\>500 ka), or have been affected by low erosion rates (\<1 m Ma−1), measurement of two cosmogenic nuclides with different half-lives thus allow accurate elevations to be determined with a reasonable uncertainty (\<1000 m at 1$sigma$). For shorter exposure durations, the method is able to constrain minimum elevations. The main advantage of the method is that it is only slightly sensitive to erosion : even if the preservation state of the surface is unknown, the bias on the computed elevation remains lower than 1500 m in most cases. The approach can also be applied to previously exposed surfaces that have subsequently been buried, in order to reconstruct the paleo-elevation of a given surface over time ranges of �`u0 to 8 Ma (using the 26Al--10Be pair) and �`u0 to 12 Ma (using the 10Be--21Ne pair).Data comparison -- We tested the method using the multiple cosmogenic nuclides dataset available for the western arid tropical Andes. The altitudes computed using the cosmogenic nuclide concentrations agree within uncertainties with the reported sampling altitudes over a range of 0 to more than 4000 m, illustrating the applicability of the method. Altitudes computed under the assumptions of continuous exposure or steady state erosion yields best fits that are statistically in agreement and close to the 1:1 line for both the 26Al--10Be and the 21Ne--10Be dataset. The 21Ne--10Be inventories in samples that have been exposed for more than 5 Ma yield elevations that are several hundreds of meters below their present-day elevations (�`u1000 m). This may result from a post 10 Ma uplift of the West Andes, or from an unrecognized exposure underwater, or below a soil cover.Implications -- This study may also have implications in other fields that rely on multiple cosmogenic nuclide measurements. The same approach might notably be used to compute the depth of exposure of samples located below the rock surface or underwater. This study may also help to improve the accuracy of the common burial dating method that uses multiple radioactive cosmogenic nuclides. For long pre-burial exposures (\>500 ka), or low erosion rates (\<1 m Ma−1), the values of the pre-burial nuclides ratios indeed depend strongly on the altitude of exposure. It may be important to consider the pre-burial altitude of exposure in order to calculate accurate burial ages.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blard_etal2019_2,

title = {Two MATLAB programs for computing paleo-elevations and burial ages from paired-cosmogenic nuclides},

author = {P. H. Blard and M. Lupker and M. Rousseau and J. Tesson},

doi = {10.1016/j.mex.2019.05.017},

year  = {2019},

date = {2019-01-01},

journal = {MethodsX},

volume = {6},

pages = {1547--1556},

abstract = {Methods based on cosmic-ray produced nuclides are key to improve our understanding of the Earth surface dynamic. Measuring multiple cosmogenic nuclides in the same rock sample has a great potential, but data interpretation requires rigorous and often complex mathematical treatments. In order to make progress on this topic, this paper presents two easy-to-use MATLABtextcopyright programs permitting to derive information from pairs of cosmogenic nuclides (26Al-10Be or 10Be-21Ne) measured in rock samples that have been exposed to cosmic rays in the past: textquotelefttextquoteleftPaleoaltitude.mtextquoterighttextquoteright and textquotelefttextquoteleftBurial.mtextquoterighttextquoteright Codes available here as supplementary material.textbullet textquotelefttextquoteleftPaleoaltitude.mtextquoterighttextquoteright computes paleoelevations from a sample whose burial age is known. This new paleoaltimetry method is presented in detail in Blard et al. [1]. The present article also develops the mathematical approach.textbullet Since the elevation of exposure may affect the accuracy of a burial age [1], the second MATLABtextcopyright script textquotelefttextquoteleftBurial.mtextquoterighttextquoteright is designed to compute burial ages from 26Al-10Be or 10Be-21Ne pairs, taking into account the position of a sample (elevation and latitude) during its preburial exposure history.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Charreau_etal2019,

title = {Basinga: A cell-by-cell GIS toolbox for computing basin average scaling factors, cosmogenic production rates and denudation rates},

author = {J. Charreau and P. H. Blard and J. Zumaque and L. C. P. Martin and T. Delobel and L. Szafran},

doi = {10.1002/esp.4649},

year  = {2019},

date = {2019-01-01},

journal = {Earth Surface and Processes and Landforms},

volume = {44},

pages = {2349--2365},

abstract = {The calculation of denudation rates from the measured cosmogenic nuclide concentrations in river sediments requires assumptions and approximations. Several different approaches and numerical tools are available in the literature. A widely used analytical approach represents the muogenic production with one or two exponentials, assumes the attenuation length of muons to be constant and also neglects temporal variations in the Earthtextquoterights magnetic field. The denudation rates are then calculated directly and analytically from the measured concentrations. A second numerical and iterative approach was more recently proposed and considersa more rigorous muogenic production law based on pre-calculated variable attenuation length of muons and accounts for temporal changes of the magnetic field. It also assumes a specific distribution of denudation rates throughout the basin and uses an iterative approach to calculate the basin average denudation rates. We tested the two approaches across several natural basins and found that both approaches provide similar denudation results. Hence, assuming exponential muogenic production and constant attenuation length of muons in the rock has little impact on the derived denudation rates. Therefore, unless a priori known distributions of denudation rates are to be tested, there does not appear to be any particular gain from using the second iterative method which is computationally less effective. Based on these findings, we developed and describe here Basinga, a new ArcGIS® and QGIS toolbox which computes the basin average scaling factors, cosmogenic production rates and denudation rates for several tens of drainage basins together. Basinga follows either the Lal/Stone or the Lifton/Sato/Dunai scaling schemes and includes several optional tools for correcting for topographicshielding, ice cover and lithology. We have also developed an original method for correcting the cosmogenic production rates for past variations in the Earthtextquoterights magnetic field.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mariotti_etal2019,

title = {Denudation systematics inferred from in situ cosmogenic 10Be concentrations in fine (50--100thinspacetextmum) and medium (100--250thinspacetextmum) sediments of the Var River basin, southern French Alps},

author = {A. Mariotti and P. H. Blard and J. Charreau and C. Petit and S. Molliex and ASTER Team.},

doi = {10.5194/esurf-7-1059-2019},

year  = {2019},

date = {2019-01-01},

journal = {Earth Surface Dynamics},

volume = {7},

pages = {1059--1074},

abstract = {Marine sedimentary archives are well dated and often span several glacial cycles ; cosmogenic 10Be concentrations in their detrital quartz grains could thus offer the opportunity to reconstruct a wealth of past denudation rates. However, these archives often comprise sediments much finer (\<250thinspacetextmum) than typically analyzed in 10Be studies, and few studies have measured 10Be concentrations in quartz grains smaller than 100thinspacetextmum or assessed the impacts of mixing, grain size, and interannual variability on the 10Be concentrations of such fine-grained sediments. Here, we analyzed the in situ cosmogenic 10Be concentrations of quartz grains in the 50--100 and 100--250thinspacetextmum size fractions of sediments from the Var basin (southern French Alps) to test the reliability of denudation rates derived from 10Be analyses of fine sands. The Var basin has a short transfer zone and highly variable morphology, climate, and geology, and we test the impact of these parameters on the observed 10Be concentrations. Both analyzed size fractions returned similar 10Be concentrations in downstream locations, notably at the Vartextquoterights outlet, where concentrations ranged from (4.02textpm0.78)texttimes104 to (4.40textpm0.64)texttimes104thinspaceatomsthinspaceg−1 of quartz. By comparing expected and observed 10Be concentrations at three major river junctions, we interpret that sediment mixing is efficient throughout the Var basin. We resampled four key locations 1thinspaceyear later, and despite variable climatic parameters during that period, interannual 10Be concentrations were in agreement within uncertainties, except for one upper subbasin. The 10Be-derived denudation rates of Var subbasins range from 0.10textpm0.01 to 0.57textpm0.09thinspacemmthinspaceyr−1, and spatial variations are primarily controlled by the average subbasin slope. The integrated denudation rate of the entire Var basin is 0.24textpm0.04thinspacemmthinspaceyr−1, in agreement with other methods. Our results demonstrate that fine-grained sediments (50--250thinspacetextmum) may return accurate denudation rates and are thus potentially suitable targets for future 10Be applications, such as studies of paleo-denudation rates using offshore sediments.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Charreau_etal2018,

title = {Late Pleistocene acceleration of deformation across the northern Tianshan piedmont (China) evidenced from the morpho-tectonic evolution of the Dushanzi anticline},

author = {J. Charreau and D. Saint-Carlier and J. Lav\'{e} and S. Dominguez and P. H. Blard and J. P. Avouac and N. D. Brown and L. C. Malatesta and W. Shengli and E. J. Rhodes},

doi = {10.1016/j.tecto.2018.02.016},

year  = {2018},

date = {2018-01-01},

journal = {Tectonophysics},

volume = {730},

pages = {132--140},

abstract = {We document the temporal evolution of deformation in the northern Tianshan piedmont where the deformation is partitioned across several thrusts and folds. We focus on the Dushanzi anticline, where abandoned terraces and growth strata allow us to constrain the history of folding since the Miocene. Based on subsurface seismic imaging, structural measurements and morphological analysis, we show that this anticline is associated with two decollement levels. We use kink band migration in growth strata dated by paleomagnetism to constrain the shortening from the Mio-Pliocene to the Holocene. Our results show that the Dushanzi anticline has been active since at least 8 Ma and that the fold grew at a steady shortening rate of 0.6 textpm 0.1 mm/yr from 8 to textasciitilde1.5 Ma with possible variations from 2.5 to 1.5 Ma. Then it accelerated rapidly to a rate of 4.3 textpm 1.0 mm/yr over at least the last 100 ka. These results, together with similar temporal shortening evolutions across other structures, suggest that the deformation rate across the eastern Tianshan piedmont increased relatively recently. This may reflect either a redistribution of the deformation from the internal structures toward the borders or a general acceleration of the deformation across the entire range.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marechal_etal2018,

title = {Active tectonics around the Yakutat indentor: New geomorphological constraints on the eastern Denali, Totschunda and Duke River Faults},

author = {A. Marechal and J. F. Ritz and M. Ferry and S. Mazzotti and P. H. Blard and R. Braucher and D. Saint-Carlier},

doi = {10.1016/j.epsl.2017.10.051},

year  = {2018},

date = {2018-01-01},

journal = {Earth and Planetary Science Letters},

volume = {482},

pages = {71--80},

abstract = {The Yakutat collision in SE Alaska -- SW Yukon is an outstanding example of indentor tectonics. The impinging Yakutat block strongly controls the pattern of deformation inland. However, the relationship between this collision system and inherited tectonic structures such as the Denali, Totschunda, and Duke River Faults remains debated. A detailed geomorphological analysis, based on high-resolution imagery, digital elevation models, field observations, and cosmogenic nuclide dating, allow us to estimate new slip rates along these active structures. Our results show a vertical motion of 0.9 textpm 0.3 mm/yr along the whole eastern Denali Fault, while the dextral component of the fault tapers to less than 1 mm/yr �`u80 km south of the Denali--Totschunda junction. In contrast, the Totschunda Fault accommodates 14.6 textpm 2.7 mm/yr of right-lateral strike-slip along its central section �`u100 km south of the junction. Further south, preliminary observations suggest a slip rate comprised between 3.5 and 6.5 mm/yr along the westernmost part of the Duke River thrust fault. Our results highlight the complex partitioning of deformation inland of the Yakutat collision, where the role and slip rate of the main faults vary significantly over distances of �`u100 km or less. We propose a schematic model of present-day tectonics that suggests ongoing partitioning and reorganization of deformation between major inherited structures, relay zones, and regions of distributed deformation, in response to the radial stress and strain pattern around the Yakutat collision eastern syntaxis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Martins_etal2018,

title = {Lake Tauca highstand (Heinrich Stadial 1a) driven by a southward shift of the Bolivian High},

author = {L. Martins and P. H. Blard and J. Lav\'{e} and T. Condom and M. Pr\'{e}maillon and V. Jomelli and D. Brunstein and M. Lupker and J. Charreau and V. Mariotti and B. Tibari and ASTER Team. and E. Davy},

year  = {2018},

date = {2018-01-01},

journal = {Science Advances},

volume = {4},

abstract = {Heinrich events are characterized by worldwide climate modifications. Over the Altiplano endorheic basin (high tropical Andes), the second half of Heinrich Stadial 1 (HS1a) was coeval with the highstand of the giant paleolake Tauca.However, the atmospheric mechanisms underlying this wet event are still unknown at the regional to global scale. We use cosmic-ray exposure ages of glacial landforms to reconstruct the spatial variability in the equilibrium line altitudeof the HS1a Altiplano glaciers. By combining glacier and lake modeling, we reconstruct a precipitation map for the HS1a period. Our results show that paleoprecipitation mainly increased along the Eastern Cordillera, whereas thesouthwestern region of the basin remained relatively dry. This pattern indicates a southward expansion of the easterlies, which is interpreted as being a consequence of a southward shift of the Bolivian High. The results provide a new understanding of atmospheric teleconnections during HS1 and of rainfall redistribution in a changing climate.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Sartgou_etal2018,

title = {Deciphering landscape evolution with karstic networks: A Pyrenean case study},

author = {A. Sart\'{e}gou and D. L. Bourl`es and P. H. Blard and R. Braucher and B. Tibari and L. Zimmermann and L. Leanni and ASTER Team. and G. Auma^itre and K. Keddadouche},

doi = {10.1016/j.quageo.2017.09.005},

year  = {2018},

date = {2018-01-01},

journal = {Quaternary Geochronology},

volume = {43},

pages = {12--29},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Stuart_etal2018,

title = {Dr. Pete Burnard (1965-2015)},

author = {F. Stuart and P. H. Blard and A. Caracausi and D. Hilton},

year  = {2018},

date = {2018-01-01},

journal = {Chemical Geology},

volume = {480},

pages = {1--2},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zimmermann_etal2018,

title = {A new all-metal induction furnace for noble gas extraction},

author = {L. Zimmermann and G. Avice and P. H. Blard and B. Marty and E. F\"{u}ri and P. G. Burnard},

doi = {10.1016/j.chemgeo.2017.09.018},

year  = {2018},

date = {2018-01-01},

journal = {Chemical Geology},

volume = {480},

pages = {86--92},

abstract = {A new all-metal induction furnace for extraction of all noble gases from pyroxenes, olivines, quartz or barites has been developed at CRPG. It differs in design from other induction furnaces in that the totality of the vacuum vessel is metallic and the induction coil, normally located outside the furnace, has been placed inside the vacuum vessel, with a special radio frequency power feedthrough welded onto a flange. The volume of the crucible is ≈15 cm3 and permits fusion of samples with a mass of up to 1 g. Samples are packed into a metal foil, loaded into a carousel, baked out before analysis, and then sequentially dropped into the Ta-crucible. The lowweight of the crucible (≈120 g) allows for short and efficient degassing cycles. When the furnace is pumped for the first time after samples loading, short cycles between 500 and 1800 textdegreeC at fast heating rates (≈400 textdegreeCtextperiodcenteredmin−1) are sufficient to achieve very low blanks. The durations of these cycles are range from 30 min for He to up to a few hours for Ne, Kr and Xe. Blanks of He, Kr and Xe (10 min heating durations) and Ne (20 min) in static vacuum are (1.6 textpm 1.0)texttimes10−15 mol 4He (T=1750 textdegreeC), (5.8 textpm 2.3)texttimes10−17 mol 20Ne (T=1500 textdegreeC), (2.1 textpm 0.3)texttimes10−18 mol 84Kr (T=1700 textdegreeC) and (4.4 textpm 0.4)texttimes10−18 mol 132Xe (T=1700 textdegreeC). Argon blanks have not yet been measured.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Charreau_etal2017,

title = {Denudation outpaced by crustal thickening in the eastern Tianshan},

author = {J. Charreau and D. Saint-Carlier and S. Dominguez and J. Lav\'{e} and P. H. Blard and J. P. Avouac and M. Jolivet and Y. Chen and S. L. Wang and N. D. Brown and L. C. Malatesta and E. Rhodes and ASTER Team},

doi = {10.1016/j.epsl.2017.09.025},

year  = {2017},

date = {2017-01-01},

journal = {Earth and Planetary Science Letters},

volume = {479},

pages = {179--191},

abstract = {The modern high topography of the Tianshan resulted from the reactivation of a Paleozoic orogenic belt by the India/Asia collision. Today, the range exhibits tectonically active forelands and intermontane basins. Based on quantitative morphotectonic observations and age constraints derived from cosmogenic 10Be dating, single-grain post-infrared infrared stimulated luminescence (p-IR IRSL) dating and modeling of fault scarp degradation, we quantify the deformation in the Nalati and Bayanbulak intermontane basins in the central Eastern Tianshan. Our results indicate that at least 1.4mm/yr of horizontal crustal shortening is accommodated within these two basins. This shortening represents over 15% of the 8.5 textpm0.5mm/yr total shortening rate across the entire range at this longitude. This shortening rate implies that the Eastern Central Tianshan is thickening at a mean rate of �`u1.4mm/yr, a rate that is significantly higher than the average denudation rate of 0.14mm/yr derived from our cosmogenic analysis. This discrepancy suggests that the Tianshan range has not yet reached a steady-state topography and remains in a transient state of topographic growth, most likely due to limited denudation rates driven by the arid climate of Central Asia.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jomelli_etal2017,

title = {Revisiting the Andean tropical glacier behavior during the Antarctic cold reversal},

author = {V. Jomelli and L. Martin and P. H. Blard and V. Favier and M. Vuill\'{e} and J. L. Ceballos},

year  = {2017},

date = {2017-01-01},

journal = {Cuadernos de Investigacion de Geografica},

number = {43(2)},

pages = {629--648},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Malatesta_etal2017,

title = {Lag and mixing during sediment transfer across the Tian Shan piedmont caused by climate-driven aggradation-incision cycles},

author = {L. C. Malatesta and J. P. Avouac and N. D. Brown and S. F. M. Breitenbach and J. Pan and M. L. Chevalier and E. Rhodes and D. Saint-Carlier and W. Zhang and J. Charreau and J. Lav\'{e} and P. H. Blard},

year  = {2017},

date = {2017-01-01},

journal = {Basin Research},

volume = {30},

number = {4},

pages = {613--635},

abstract = {Transient sediment storage and mixing of deposits of various ages during transport across alluvial piedmonts alter the clastic sedimentary record. We quantify buffering and mixing during cycles of aggradation--incision in the north piedmont of the Eastern Tian Shan. We complement existing chronologic data with 20 new luminescence ages and one cosmogenic radionuclide age of terrace abandonment and alluvial aggradation. Over the last 0.5 Myr, the piedmont deeply incised and aggraded many times per 100 kyr. Aggradation is driven by an increased flux of glacial sediment accumulated in the high range and flushed onto the piedmont by greater water discharge at stadial--interstadial transitions. After this sediment is evacuated from the high range, the reduced input sediment flux results in fluvial incision of the piedmont as fast as 9 cm year−1 and to depths up to 330 m. The timing of incision onset is different in each river and does not directly reflect climate forcing but the necessary time for the evacuation of glacial sediment from the high range. A significant fraction of sediments evacuated from the high range is temporarily stored on the piedmont before a later incision phase delivers it to the basin. Coarse sediments arrive in the basin with a lag of at least 7--14 kyrs between the first evacuation from the mountain and later basinward transport. The modern output flux of coarse sediments from the piedmont contains a significant amount of recycled material that was deposited on the piedmont as early as the Middle Pleistocene. Variations in temperature and moisture delivered by the Westerlies are the likely cause of repeated aggradation--incision cycles in the north piedmont instead of monsoonal precipitation. The arrival of the gravel front into the proximal basin is delayed relative to the fine‐grained load and both are separated by a hiatus. This work shows, based on field observations and data, how sedimentary systems respond to climatic perturbations, and how sediment recycling and mixing can ensue.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Martin_etal2017,

title = {The CREp program and the ICE-D production rate calibration database: A fully parameterizable and updated online tool to compute cosmic- ray exposure ages},

author = {L. C. P. Martin and P. H. Blard and G. Balco and J. Lav\'{e} and R. Delunel and N. Lifton and V. Laurent},

doi = {10.1016/j.quageo.2016.11.006},

year  = {2017},

date = {2017-01-01},

journal = {Quaternary Geochronology},

volume = {38},

pages = {25--49},

abstract = {Over the last decades, cosmogenic exposure dating has permitted major advances in many fields of Earth surface sciences and particularly in paleoglaciology. Yet, exposure age calculation remains a complicated and dense procedure. It requires numerous choices of parameterization and the use of an accurate production rate.This study describes the CREp program (http://crep.crpg.cnrs-nancy.fr) and the ICE-D production rate online database (http://calibration.ice-d.org). This system is designed so that the CREp calculator will automatically reflect the current state of this global calibration database production rate, ICE-D. ICE-D will be regularly updated in order to incorporate new calibration data and reflect the current state of the available literature. CREp is a Octave/Matlabtextcopyright online code that computes Cosmic Ray Exposure (CRE) ages for 3He and 10Be. A stand-alone version of the CREp code is also released with the present article. Note however that only the online version is connected to the online database ICE-D. The CREp program offers the possibility to calculate ages with two scaling models: i.e. the empirical Lal-Stone time-dependent model (Balco et al., 2008; Lal, 1991; Stone, 2000) with the muon parameters of Braucher et al. (2011), and the Lifton-Sato-Dunai (LSD) theoretical model (Lifton et al., 2014). The default atmosphere model is the ERA-40 data-base (Uppala et al., 2005), but one may also use the standard atmosphere for comparison (N.O.A.A, 1976). To perform the time-dependent correction, users may import their own geomagnetic database for paleomagnetic corrections or opt for one of the three proposed datasets (Lifton, 2016; Lifton et al., 2014; Muscheler et al., 2005). For the important choice of the production rate, CREp is linked to a database of production rate calibration data that is part of the ICE-D (Informal Cosmogenic-nuclide Exposure-age Database) project (http://calibration.ice-d.org). This database includes published empirical calibration rate studies that are publicly available at present, comprising those of the CRONUS-Earth and CRONUS-EU projects, as well as studies from other projects. In the present study, the efficacy of the different scaling models has alsobeen evaluated looking at the statistical dispersion of the computed Sea Level High Latitude (SLHL) production rates. Lal/Stone and LSD models have comparable efficacies, and the impact of the tested atmospheric model and the geomagnetic database is also limited. Users however have several possibilities to select the production rate: 1) using a worldwide mean value, 2) a regionally averaged value (not available in regions with no data), 3) a local unique value, which can be chosen among the existing dataset or imported by the user, or 4) any combination ofmultiple calibration data. If a global mean is chosen, the 1s uncertainty arising from the production rate is about 5% for 10 Be and 10% for 3 He. If a regional production rate is picked, these uncertainties are potentially lower.CREp is able to calculate a large number of ages in a reasonable time (typically\<30 s for 50 samples). The user may export a summary table of the computed ages and the density probability function associated with each age (in the form of a spreadsheet).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Puchol_etal2017,

title = {Variability of magmatic and cosmogenic 3 He in Ethiopian river sands of detrital pyroxenes: Impact on denudation rate determinations},

author = {N. Puchol and P. H. Blard and R. Pik and B. Tibari and J. Lav\'{e}},

doi = {0.1016/j.chemgeo.2016.10.033},

year  = {2017},

date = {2017-01-01},

journal = {Chemical Geology},

volume = {448},

pages = {13--25},

abstract = {In-situ cosmogenic 3He is a robust tool for determining denudation rates or exposure ages of lavas bearing mafic phenocrysts. However, analyses are often complicated by the presence of several helium sources. In particular, in old magmatic rocks with high radiogenic 4He contents, discriminating cosmogenic 3He from magmatic 3He is not straightforward since these varieties may vary largely between aliquots. We sampled sands from the Tekeze and Mile rivers, both draining the basaltic Ethiopian highlands, an area where erosion patterns are intimately linked to the development of the Western Afar margin and to heterogeneous monsoon precipitation. From each river we analyzed textasciitilde15 aliquots of pyroxenes having variable grain sizes (0.3 mm up to N 1 mm). The total 3 He is both higher and more scattered in the bigger grains. Crushing of these largest grains and subsequent melting of the powder tends to produce more homogeneous 3 He values, suggesting that magmatic 3He hosted in inclusions is responsible for most of the inter-aliquot variability. We also performed a Monte Carlo simulation based on a numerical denudation model of the two watersheds. The simulation confirms that cosmogenic3 He variability cannot be responsible for the observed scatter since the cosmogenic 3 He variability is averaged away and unobservable in aliquots of textasciitilde200 grains. A compilation of previously published data also indicates that magmatic helium can be significantly variable, even between pre-crushed aliquots. Hence, magmatic helium, unlike cosmogenic 3 He, is highly variable, even in the case of aliquots of hundreds of grains. We suggest this is due to a strong nugget effect, possibly due to large fluid (or melt)-inclusions contained in phenocrysts.In addition, the fact that small and big grains have comparable radiogenic 4 He concentrations suggests that grain fragmentation during river transport is responsible for the lower magmatic helium content of the smallest grains. Therefore, one should preferably use small grain (0.2--0.5 mm) granulometry for in-situ cosmogenic 3 He analysis in mafic phenocrysts. Using the measured cosmogenic3 He, we calculate basin-averaged denudation rates of 70 textpm 20 and 57 textpm 5mmkyr − 1 , for the Mile and for the Tekeze river, respectively. These values are coherent with long-term denudation rates previously proposed from low-temperature thermochronology.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Puchol_etal2017_2,

title = {Limited impact of Quaternary glaciations on denudation rates in Central Asia},

author = {N. Puchol and J. Charreau and P. H. Blard and J. Lav\'{e} and S. Dominguez and R. Pik and D. Saint-Carlier and ASTER Team},

doi = {10.1130/B31475.1},

year  = {2017},

date = {2017-01-01},

journal = {GSA Bulletin},

volume = {129},

number = {3-4},

pages = {479--499},

abstract = {Because of its essential role in coupling climate and tectonics, denudationis a key parameter when constraining the history of Earthtextquoterightssurface. This is particularly true at the Pliocene-Pleistocene transition,and the potential impact of the onset of Quaternary glaciationsremains strongly debated. In the present study, we measured in situcosmogenic 10Be within continuous late Cenozoic sedimentary sectionsthat had already been dated using magnetostratigraphy. Thenew data were obtained from four sedimentary basins in the northernand southern Tianshan range (Central Asia). We first thoroughly discusshow in situ cosmogenic 10Be concentrations can be corrected forradioactive decay and for the contribution of postdepositional cosmogenicaccumulation to derive the paleo--denudation rates. Our analysisshows that, in the four sedimentary records, the potential bias remainslow enough to consider the derived denudation rates reliable.The four records, although likely influenced by local particularitiesdue to lithological heterogeneity and local tectonics, display similartrends of continuously increasing denudation between ca. 9 Ma andthe present. These rates have remained relatively high but steadysince 4 Ma, textasciitilde1.5 m.y. before the onset of the Quaternary glacial cycles.Though the rejuvenation of the Tianshan range since 11 Ma may explainmost of the progressive increase (texttimes5) in denudation, our datasuggest that the Quaternary glaciations had only a limited impact ondenudation in the Tianshan. Our data, however, indicate an increasein the spatial and high-frequency variability (\<1 m.y.) of the denudationrates between 3 and 1 Ma. This may correspond to a transientreadjustment of the landscape in response to the onset of Quaternaryglacial cycles},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zerathe_etal2017,

title = {Toward the feldspar alternative for cosmogenic 10 Be applications},

author = {S. Zerathe and P. H. Blard and R. Braucher and D. L. Bourl`es and L. Audin and J. Carcaillet and F. Delgado and C. Benavente and ASTER Team},

doi = {10.1016/j.quageo.2017.06.004},

year  = {2017},

date = {2017-01-01},

journal = {Quaternary Geochronology},

volume = {41},

pages = {83--96},

abstract = {The possibility of quantifying surface processes in mafic or volcanic environment using the potentialities offered by the in situ-produced cosmogenic nuclides, and more specifically by the in situ-produced 10Be, is often hampered by the rarity of quartz minerals in the available lithologies. As an alternative to overcome this difficulty, we explore in this work the possibility of relying on feldspar minerals rather that on quartz to perform in situ-produced 10Be measurements in such environments. Our strategy was to cross-calibrate the total production rate of 10Be in feldspar (P10fsp) against the total production rate of 3He in pyroxene (P3px) by measuring 3He and 10Be in cogenetic pyroxene (3Hepx) and feldspar (10Befsp). The samples were collected from eight ignimbritic boulders, exposed from ca 120 to 600 ka at elevations ranging from 800 to 2500 m, along the preserved rock-avalanche deposits of the giant Caquilluco landslide (18textdegreeS, 70textdegreeW), Southern Peru. Along with data recently published by Blard et al. (2013a) at a close latitude (22textdegreeS) but higher elevation (ca. 4000 m), the samples yield a remarkably tight cluster of 3Hepx ?\u{I} 10Befsp total production ratios whose weighted-mean is 35.6 textpm 0.5 (1$sigma$). The obtained weighted-mean 3Hepx ?\u{I} 10Befsp total production ratio combined with the local 3Hepy total production rate in the high tropical Andes published by Martin et al. (2017) allows to establish a total SLHL 10Be in situ-production rate in feldspar mineral (P10fsp) of 3.57 textpm 0.21 at.g−1.yr−1 (scaled for the LSD scaling scheme, the ERA40 atm model and the VDM of Lifton, 2016).Despite the large elevation range covered by the whole dataset (800--4300 m), no significant variation of the 3Hepx ?\u{I} 10Befsp total production ratios in pyroxene and feldspar was evidenced. As an attempt to investigate the effect of the chemical composition of feldspar on the total 10Be production rate, major and trace element concentrations of the studied feldspar samples were analyzed. Unfortunately, giving the low compositional variability of our dataset, this issue is still pending.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blard_etal2016,

title = {Climate science: The history of Greenlandtextquoterights ice},

author = {P. H. Blard and G. Leduc and N. Glasser},

year  = {2016},

date = {2016-01-01},

journal = {Nature},

volume = {540},

number = {7632},

pages = {202--203},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Delunel_etal2016,

title = {Long term low latitude and high elevation cosmogenic 3He production rate inferred from a 107 ka-old lava flow in northern Chile; 22textdegreeS-3400 m a.s.l.},

author = {R. Delunel and P. H. Blard and L. C. P. Martin and S. Nomade and F. Sclunegger},

doi = {10.1016/j.gca.2016.04.023},

year  = {2016},

date = {2016-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {184},

number = {71-87},

abstract = {Available geological calibration sites used to estimate the rate at which cosmogenic 3He is produced at the Earthtextquoterights surface are mostly clustered in medium to high latitudes. Moreover, most of them have exposure histories shorter than tens of thousands of years. This lack of sites prevents a qualitative assessment of available production models used to convert cosmogenic 3He concentrations into exposure ages and/or denudation rates. It thus limits our ability to take into account the atmospheric, geomagnetic and solar modulation conditions that might have affected the production of cosmogenic nuclides in the past for longer exposure histories and in low latitude regions. We present the cosmogenic 3He production rate inferred from a new geological calibration site located in northern Chile. Five samples were collected on the surface of the largest and bestpreserved lava flow of the San Pedro volcano (21.934textdegreeS--68.510textdegreeW-3390 m a.s.l.), which displays pristine crease-structure features. 40Ar/39Ar dating yields a reliable plateau age of 107 textpm 12 ka for the eruption of this lava flow. Eight pyroxene aliquots separated from the surface samples yield a weighted average cosmogenic 3He concentration of 99.3 textpm 1.2 Mat g-1 from which a local cosmogenic 3He production rate of 928 textpm 101 at g-1 yr-1 is calculated. The local production rate is then scaled to a sea level high latitude (SLHL) reference position using different combinations of geographic spatialization schemes, atmosphere models and geomagnetic field reconstructions, yielding SLHL production rates between 103 textpm 11 and 130 textpm 14 at g-1 yr-1 consistent with the most recent estimates available from the literature. Finally, we use the same scaling frameworks to re-evaluate the mean global-scale cosmogenic 3He production rate in olivine and pyroxene minerals at 120 textpm 16 at g-1 yr-1 from the compilation of previously published calibration datasets},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Medynski_etal2016,

title = {Magmatic cycles pace tectonic and morphological expression of rifting (Afar depression, Ethiopia)},

author = {S. Medynski and R. Pik and P. Burnard and S. Dumont and R. Grandin and A. Williams and P. H. Blard and I. Schimmelpfennig and C. Vye-Brown and L. France and D. Ayalew and L. Benedetti and G. Yirgu and ASTER team},

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

year  = {2016},

date = {2016-01-01},

journal = {Earth and Planetary Science Letters},

volume = {446},

pages = {77--88},

abstract = {The existence of narrow axial volcanic zones of mid-oceanic ridges testifies of the underlying concentration of both melt distribution and tectonic strain. As a result of repeated diking and faulting, axial volcanic zones therefore represent a spectacular topographic expression of plate divergence. However, the submarine location of oceanic ridges makes it difficult to constrain the interplay between tectonic and magmatic processes in time and space. In this study, we use the Dabbahu--Manda Hararo (DMH) magmatic rift segment (Afar, Ethiopia) to provide quantitative constraints on the response of tectonic processes to variations in magma supply at divergent plate boundaries. The DMH magmatic rift segment is considered an analogue of an oceanic ridge, exhibiting a fault pattern, extension rate and topographic relief comparable to intermediate- to slow-spreading ridges. Here, we focus on the northern and central parts of DMH rift, where we present quantitative slip rates for the past 40 kyr for major and minor normal fault scarps in the vicinity of a recent (September 2005) dike intrusion. The data obtained show that the axial valley topography has been created by enhanced slip rates that occurred during periods of limited volcanism, suggestive of reduced magmatic activity, probably in association with changes in strain distribution in the crust. Our results indicate that the development of the axial valley topography has been regulated by the lifetimes of the magma reservoirs and their spatial distribution along the segment, and thus to the magmatic cycles of replenishment/differentiation (\<100 kyr). Our findings are also consistent with magma-induced deformation in magma-rich rift segments. The record of two tectonic events of metric vertical amplitude on the fault that accommodated the most part of surface displacement during the 2005 dike intrusion suggests that the latter type of intrusion occurs roughly every 10 kyr in the northern part of the DMH segment.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Protin_etal2016,

title = {Irreversible adsorption of atmospheric helium on olivine: A lobster pot analogy},

author = {M. Protin and P. H. Blard and Y. Marrocchi and F. Mathon},

doi = {10.1016/j.gca.2016.01.032},

year  = {2016},

date = {2016-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {179},

pages = {76--88},

abstract = {This study reports new experimental results that demonstrate that large amounts of atmospheric helium may be adsorbed onto the surfaces of olivine grains. This behavior is surface-area-related in that this contamination preferentially affects grains that are smaller than 125 lm in size. One of the most striking results of our study is that in vacuo heating at 900 textdegreeC for 15 min is not sufficient to completely remove the atmospheric contamination. This suggests that the adsorption of helium may involve high-energy trapping of helium through irreversible anomalous adsorption. This trapping process of helium can thus be compared to a textquotelefttextquoteleftlobster pottextquoterighttextquoteright adsorption: atmospheric helium easily gets in, but hardly gets out. While this type of behavior has previously been reported for heavy noble gases (Ar, Kr, Xe), this is the first time that it has been observed for helium. Adsorption of helium has, until now, generally been considered to be negligible on silicate surfaces. Our findings have significant implications for helium and noble gas analysis of natural silicate samples, such as for cosmic-ray exposure dating or noble gas characterization of extraterrestrial material. Analytical procedures in future studies should be adapted in order to avoid this contamination. The results of this study also allow us to propose an alternative explanation for previously described matrix loss of cosmogenic 3He.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ritz_etal2016,

title = {Active tectonics within the NW and SE extensions of the Pambak- Sevan-Syunik fault: Implications for the present geodynamics of Armenia},

author = {J. F. Ritz and A. Avagyan and M. Mkrtchyan and H. Nazari and P. H. Blard and A. Karakhanian and H. Philip and S. Balescu and S. Mahan and S. Huot and P. M\"{u}nch and M. Lamothe},

doi = {10.1016/j.quaint.2015.05.021},

year  = {2016},

date = {2016-01-01},

journal = {Quaternary International},

volume = {395},

pages = {61--78},

abstract = {This study analyzes the active tectonics within the northwestern and southeastern extensions of the Pambak-Sevan-Syunik fault (PSSF), a major right-lateral strike-slip fault cutting through Armenia. Quantifying the deformations in terms of geometry, kinematics, slip rates and earthquake activity, usingcosmogenic 3He, OSL/IRSL and radiocarbon dating techniques, reveal different behaviors between the two regions. Within the northwestern extension, in the region of Amasia, the PSSF bends to the west and splits into two main WNWeESE trending reverse faults defining a compressional pop-up structure. We estimate an uplift rate and a shortening rate of 0.5 textpm 0.1 mm/y and 1.4 textpm 0.6 mm/y, respectively. This suggests that most of the textasciitilde2 mm/y right lateral movement of the PSSF seems to be absorbed within the Amasia pop-structure. Within the southeastern extension, the PSSF shows signs of dying out within the Tsghuk Volcano region at the southernmost tip of the Syunik graben. There, the tectonic activity ischaracterized by a very slow NS trending normal faulting associated with a slight right-lateral movement. Slip rates analyses (i.e. vertical slip rate, EW stretching rate at 90textdegree to the fault, and right-lateral slip rate of textasciitilde0.2 mm/y, textasciitilde0.1 mm/y and textasciitilde0.05 mm/y, respectively) lead to the conclusion that the right lateral movement observed further north along the PSSF is mainly transferred within other active faults further west within the Karabagh (Hagari fault or other structures further northwestwards). Comparing our slip rates with those estimated from GPS data suggests that most of the deformation is localized and seismic,at least within the Tsghuk region. The geometrical and kinematic pattern observed within the two terminations of the PSSF suggests that the fault and its surrounding crustal blocks are presently rotating anticlockwise, as also observed within the GPS velocity field. This is consistent with the recent kinematicmodels proposed for the Caucasus-Kura-South Caspian region and brings a new insight into the present geodynamics of Armenia},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Saint-Carlier_etal2016,

title = {Major temporal variations in shortening rate absorbed along a large active fold of the southeastern Tianshan piedmont (China)},

author = {D. Saint-Carlier and J. Charreau and J. Lav\'{e} and P. H. Blard and S. Dominguez and J. P. Avouac and W. Shenli and ASTER Team},

doi = {10.1016/j.epsl.2015.11.041},

year  = {2016},

date = {2016-01-01},

journal = {Earth and Planetary Science Letters},

volume = {434},

pages = {333--348},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Schaefer_etal2016,

title = {Performance of CRONUS-P ?\u{I} A pyroxene reference material for helium isotope analysis},

author = {J. M. Schaefer and G. Winckler and P. H. Blard and G. Balco and D. L. Shuster and R. Friedrich and A. J. T. Jull and R. Wieler and C. Schluechter},

doi = {10.1016/j.quageo.2014.07.006},

year  = {2016},

date = {2016-01-01},

journal = {Quaternary Geochronology},

volume = {31},

pages = {237--239},

abstract = {Helium isotope analyses are central to modern earth science and measured by many noble gas laboratories around the globe (Burnard, 2013; Wieler et al., 2002), spanning a wide spectrum of fundamental research e from identifying primordial reservoirs in the Earth mantle to paleoclimate reconstructions.The CRONUS-Earth initiative included the manufacturing, distribution and analysis of a pyroxene reference material (CRONUS-P) that was designed to be useful for internal reliability control of 3He measurements within a few percent and potentially for 4He on a higher level of uncertainty. This short paper describes the CRONUS-P material and its performance as 3He and 4He reference sample for noble gas laboratories. The companion paper by Blard et al. 2015 describes in depth the interlaboratory helium isotope experiment within CRONUS-Earth.We show normalized helium isotope data of CRONUS-P measured at three different noble gas laboratories. Data from all three laboratories show no relation between helium isotope concentrations and sample mass, implying that the material is homogeneous. The data show that CRONUS-P is useful as an internal standard for 3He within better 2% (1s) and for 4He within better 10%.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blard_etal2015,

title = {An inter-laboratory comparison of cosmogenic 3 He and radiogenic 4 He in the CRONUS-P pyroxene standard},

author = {P. H. Blard and G. Balco and P. G. Burnard and K. Farley and C. R. Fenton and R. Friedrich and A. J. T. Jull and S. Niedermann and R. Pik and J. M. Schaefer and E. M. Scott and D. L. Shuster and F. M. Stuart and M. Stute and B. Tibari and G. Winckler and L. Zimmermann},

doi = {http://dx.do10.1016/j.quageo.2014.08.004},

year  = {2015},

date = {2015-01-01},

journal = {Quaternary Geochronology},

volume = {26},

pages = {11--19},

abstract = {This study reports an inter-laboratory comparison of the 3 He and 4 He concentrations measured in the pyroxene material CRONUS-P. This forms part of the CRONUS-Earth and CRONUS-EU programs, which also produced a series of natural reference materials for in situ produced 26Al,10Be,14C,21Ne and 36Cl.Six laboratories (GFZ Potsdam, Caltech Pasadena, CRPG Nancy, SUERC Glasgow, BGC Berkeley, Lamont New York) participated in this intercomparison experiment, analyzing between 5 and 22 aliquots each. Intra-laboratory results yield 3He concentrations that are consistent with the reported analytical uncertainties, which suggests that 3He is homogeneous within CRONUS-P. The inter-laboratory dataset (66 determinations from the 6 different labs) is characterized by a global weighted mean of(5.02textpm0.12)x109at g-1 with an overdispersion of 5.6% (2s).4He is characterized by a larger variability than 3He, and by an inter-lab global weighted mean of (3.60textpm0.18)x1013 at g-1(2s) with an overdispersion of 10.4% (2s).There are, however, some systematic differences between the six laboratories. More precisely, 2 laboratories obtained mean 3He concentrations that are about 6%higher than the clustered other 4 laboratories. This systematic bias is larger than the analytical uncertainty and not related to the CRONUS-P material (see Schaefer et al., 2015). Reasons for these inter-laboratory offsets are difficult to identify but are discussed below. To improve the precision of cosmogenic 3He dating, we suggest that future studies presenting cosmogenic 3He results also report the3He concentration measured in the CRONUS-P material in the lab(s) used in a given study},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Martin_etal2015,

title = {In situ cosmogenic 10 Be production rate in the High Tropical Andes},

author = {L. C. P. Martin and P. H. Blard and J. Lav\'{e} and R. Braucher and M. Lupker and T. Condom and J. Charreau and V. Mariotti and ASTER Team. and E. Davy},

doi = {10.1016/j.quageo.2015.06.012},

year  = {2015},

date = {2015-01-01},

journal = {Quaternary Geochronology},

volume = {30},

pages = {54--68},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PieterVermeesch_etal2015,

title = {Interlaboratory comparison of cosmogenic 21 Ne in quartz},

author = {P. Pieter Vermeesch and G. Balco and P. H. Blard and T. J. Dunai and F. Kober and S. Niedermann and D. L. Shuster and S. Strasky and F. M. Stuart and R. Wieler and L. Zimmermann},

doi = {10.1016/j.quageo.2012.11.009},

year  = {2015},

date = {2015-01-01},

journal = {Quaternary Geochronology},

volume = {26},

pages = {20--28},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Quesada_etal2015,

title = {Impact of Bolivian paleolake evaporation on the d 18 O of the Andean glaciers during the last deglaciation (18.5 e 11.7 ka): diatom-inferred d 18 O values and hydro-isotopic modeling},

author = {B. Quesada and F. Sylvestre and F. Vimeux and J. Black and C. Paill`es and C. Sonzogni and A. Alexandre and P. H. Blard and A. Tonetto and J. C. Mazur and H. Bruneton},

doi = {1016/j.quascirev.2015.04.022},

year  = {2015},

date = {2015-01-01},

journal = {Quaternary Science Reviews},

volume = {120},

pages = {93--106},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blard_etal2014,

title = {Progressive glacial retreat in the Southern Altiplano (Uturuncu volcano, 22textdegreeS) between 65 and 14 ka constrained by cosmogenic 3 He dating},

author = {P. H. Blard and J. Lav\'{e} and K. A. Farley and V. Ramirez and N. Jimenez and L. C. P. Martin and J. Charreau and B. Tibari and M. Fornari},

doi = {10.1016/j.yqres.2014.02.002},

year  = {2014},

date = {2014-01-01},

journal = {Quaternary Science Reviews},

volume = {82},

pages = {209--221},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jomelli_etal2014,

title = {A major advance of tropical Andean glaciers during the Antarctic cold reversal},

author = {V. Jomelli and V. Favier and M. Vuille and R. Braucher and L. C. P. Martin and P. H. Blard and C. Colose and D. Brunstein and F. He and M. Khodri and D. L. Bourl`es and L. Leanni and V. Rinterknecht and D. Grancher and B. Francou and J. L. Ceballos and H. Fonseca and Z. Liu and B. L. Otto-Bliesner},

doi = {10.1038/nature13546},

year  = {2014},

date = {2014-01-01},

journal = {Nature},

volume = {513},

pages = {224--228},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Poujol_etal2014,

title = {Active tectonics of the Northern Rif (Morocco) from geomorphic and geochronological data},

author = {A. Poujol and J. F. Ritz and A. Tahayt and P. Vernant and M. Condomines and P. H. Blard and J. Billant and L. Vacher and B. Tibari and L. Hni and A. Koulalildrissi},

doi = {10.1016/j.jog.2014.01.004},

year  = {2014},

date = {2014-01-01},

journal = {Journal of Geodynamics},

volume = {77},

pages = {70--88},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Puchol_etal2014,

title = {Grain-size dependent concentration of cosmogenic 10 Be and erosion dynamics in a landslide-dominated Himalayan watershed},

author = {N. Puchol and J. Lav\'{e} and M. Lupker and P. H. Blard and F. Gallo and C. France-Lanord and ASTER Team.},

doi = {10.1016/j.geomorph.2014.06.019},

year  = {2014},

date = {2014-01-01},

journal = {Geomorphology},

volume = {224},

pages = {55--68},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blard_etal2013,

title = {Cosmogenic 10Be production rate calibrated against 3He in the high Tropical Andes (3800--4900m, 20--22◦ S)},

author = {P. H. Blard and R. Braucher and J. Lav\'{e} and D. Bourl`es},

doi = {10.1016/j.epsl.2013.09.010},

year  = {2013},

date = {2013-01-01},

journal = {Earth and Planetary Science Letters},

volume = {382},

pages = {140--149},

abstract = {Many geomorphologic applications,notably glacier chronologies,require improvements in both the precision and the accuracy of the cosmogenic dating tool.Of particular importance is the need to better constraint hespatial variability of the cosmogenic nuclides production rates at high elevation and low latitudes.One strategy that can be adopted for this is to couple absolute calibrations,from independently dated surfaces,with cross-calibration studies,performed by measuring several cosmogenic nuclides in the same rock.In the present study,were port the highest-elevation(\>4800m)cross-calibration published todate,comprising measurements of cosmogenic 3He and 10Be incogenetic pyroxene and quartz.The samples were collected from six dacitic moraine boulders,exposed from 32 to 65ka at 4820m on the flanks of the Uturuncu volcano(22◦S,67◦W),Southern Lipez(Bolivia).The samples yield are markably tight cluster of 3He--10Be production ratios, with a weighted mean of 33.3textpm0.9(1$sigma$).This production ratio is undistinguishable,with inuncertainties,from the 3He--10Be production ratio of 32.3textpm0.9 determined in the same mineral pair at lowel evation (1333m)by Amidon et al.(2009).These results agree at the 1$sigma$level and suggest that any hypothetical increase of the 3He--10Be production ratio in pyroxene and quartz is likely to be lower than 5% over this elevation range(1000--5000m).Moreover,the production ratio is almost insensitive to the Li content of the pyroxene(20to50ppmLi),suggesting that the cosmogenic thermal neutron production of 3He is very low in this setting.The high-elevation 3He--10Be production ratio is used in combination with a local determination of the 3He production rate in the high Central Altiplano(3800m)(Blard et al.,2013)to establish a local 10Be production rate of 30.0textpm1.4 atg−1yr−1at 3800m and 20◦S.After scaling to sea-level high latitude with the time-dependent Lal/Stone model,this yields a10Be production rate in quartz of 3.63textpm0.17 at g−1yr−1.Importantly, this rate can be used for high-precision geomorphologic dating,for example for determining glacial chronologies(1$sigma$\<4%)through 10Be dating of moraines in the high Tropical Andes.Any inaccuracy attached to the scaling model is canceled out when the calibration site is located close to the dated object.The same experiment was also undertaken in pyroxene and plagioclase from two andesitic boulders from the Tunupavolcano moraines,exposed at 3800m and 4200m.A3He--10Be production ratio of 35.9textpm1.3(1$sigma$)is obtained for this mineral pair,indicating that the 10Be production rate in plagioclase is about 8%lower than in quartz.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blard_etal2013_2,

title = {Cosmogenic 3He production rate in the high tropical Andes (3800m,20◦S): Implications for the local last glacial maximum},

author = {P. H. Blard and J. Lav\'{e} and F. Sylvestre and C. J. Placzek and C. Claude and V. Galy and T. Condom and B. Tibari},

doi = {10.1016/j.epsl.2013.07.006},

year  = {2013},

date = {2013-01-01},

journal = {Earth and Planetary Science Letters},

volume = {377-378},

pages = {260--275},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Medynski_etal2013,

title = {Controls on magmatic cycles and development of rift topography of the Manda Hararo segment (Afar, Ethiopia):Insights from cosmogenic 3He investigation of landscape evolution},

author = {S. Medynski and R. Pik and P. Burnard and A. Williams and C. Vye-Brown and D. Ferguson and P. H. Blard and L. France and G. Yirgu and J. I. Seid and D. Ayalew and A. Calvert},

doi = {doi.org/10.1016/j.epsl.2013.02.006},

year  = {2013},

date = {2013-01-01},

journal = {Earth and Planetary Science Letters},

volume = {367},

pages = {133--145},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lupker_etal2012,

title = {10Be-derived Himalayan denudation rates and sediment budgets in the Ganga basin},

author = {M. Lupker and P. H. Blard and J. Lav\'{e} and C. France-Lanord and L. Leanni and N. Puchol and J. Charreau and D. Bourl`es},

doi = {10.1016/j.epsl.2012.04.020},

year  = {2012},

date = {2012-01-01},

journal = {Earth and Planetary Science Letters},

volume = {333-334},

pages = {146--156},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mabry_etal2012,

title = {Mapping changes in helium sensitivity and peak shape for varying parameters of a Nier-type noble gas ion source},

author = {J. Mabry and P. Burnard and P. H. Blard and L. Zimmermann},

doi = {10.1039/C2JA10339G},

year  = {2012},

date = {2012-01-01},

journal = {Journal of Analytical Atomic Spectrometry},

volume = {27},

pages = {1012--1017},

abstract = {Tuning a Nier-type ion source involves adjusting many different parameters which affect the resulting signal in complicated ways. We have mapped the sensitivity of 4He and the peak shape while varying the total extraction voltage, the half-plate bias, the repeller voltage, and the electron energy. With the particular source settings that we used, we see an asymmetric rise and fall in the sensitivity as theextraction is raised, but a symmetric rise and fall as the half-plate bias voltage is varied. The best peak shape is found generally at the same extraction value of the maximum sensitivity, but at a distinctly different half-plate bias than the maximum sensitivity; thus it is necessary to monitor the peak shape while tuning the half-plate bias. The extraction and the repeller values of the maximum sensitivity and the best peak shape are strongly correlated, and therefore these two parameters must be tuned together. And finally, we see a double-peak in the sensitivity as the electron voltage is increased, so it may be worthwhile to check a wide range of electron voltages when tuning.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Puchol_etal2012,

title = {Les nucl\'{e}ides cosmog\'{e}niques : traceurs `a haute r\'{e}solution des taux dtextquoteright\'{e}rosion au cours du temps},

author = {N. Puchol and P. H. Blard and J. Charreau and R. Pik},

year  = {2012},

date = {2012-01-01},

journal = {G\'{e}ochronique},

number = {124},

pages = {19--21},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zimmermann_etal2012,

title = {A New Single Vacuum Furnace Design for Cosmogenic 3He Dating},

author = {L. Zimmermann and P. H. Blard and P. Burnard and S. Medynski and R. Pik and N. Puchol},

doi = {10.1111/j.1751-908X.2011.00145.x},

year  = {2012},

date = {2012-01-01},

journal = {Geostandards and Geoanalytical Research},

pages = {1--9},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blard_etal2011,

title = {Lake highstands on the Altiplano (Tropical Andes) contemporaneous with Heinrich 1 and the Younger Dryas: new insights from 14C, UeTh dating and d18O of carbonates},

author = {P. H. Blard and F. Sylvestre and A. K. Tripati and C. Claude and C. Causse and A. Coudrain and T. Condom and J. L. Seidel and F. Vimeux and C. Moreau and J. P. Dumoulin and J. Lav\'{e}},

doi = {10.1016/j.quascirev.2011.11.001},

year  = {2011},

date = {2011-01-01},

journal = {Quaternary Science Reviews},

volume = {30},

pages = {3973--3989},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Charreau_etal2011,

title = {Paleo-erosion rates in Central Asia since 9 Ma: A transient increase at the onset of Quaternary glaciations?},

author = {J. Charreau and P. H. Blard and N. Puchol and J. P. Avouac and E. Lallier-Verg`es and D. Bourl`es and R. Braucher and A. Gallaud and R. Finkel and M. Jolivet and Y. Chen and P. Roy},

doi = {10.1016/j.epsl.2011.01.018},

year  = {2011},

date = {2011-01-01},

journal = {Earth and Planetary Science Letters},

volume = {304},

number = {1-2},

pages = {85--92},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jomelli_etal2011,

title = {Irregular tropical glacier retreat over the Holocene epoch driven by progressive warming},

author = {V. Jomelli and M. Khodri and V. Favier and D. Brunstein and M. P. Ledru and P. Wagnon and P. H. Blard and J. E. Sicart and R. Braucher and D. Grancher and D. Bourl`es and P. Braconnot and M. Vuille},

year  = {2011},

date = {2011-01-01},

journal = {Nature},

volume = {474},

pages = {196--199},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Schimmelpfennig_etal2011,

title = {Calibration of cosmogenic 36Cl production rates by spallation of Ca and K on in lava flows samples from Mt. Etna ( 38textdegreeN, Italy) and Payun Matru (36textdegreeS, Argentina)},

author = {I. Schimmelpfennig and L. Benedetti and V. Garreta and R. Pik and P. H. Blard and P. G. Burnard and D. Bourl`es and R. Finkel and K. Ammond and C. Dunaigre},

year  = {2011},

date = {2011-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {75},

number = {10},

pages = {2611--2632},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blard_etal2009,

title = {Late local glacial maximum in the Central Altiplano triggered by cold and locally-wet conditions during the paleolake Tauca episode (17--15 ka, Heinrich 1)},

author = {P. H. Blard and J. Lav\'{e} and K. A. Farley and M. Fornari and N. Jimenez and V. Ramirez},

doi = {10.1016/j.quascirev.2009.09.025},

year  = {2009},

date = {2009-01-01},

journal = {Quaternary Science Reviews},

volume = {28},

pages = {3414--3427},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Schimmelpfennig_etal2009,

title = {Sources of in-situ Cl-36 in basaltic rocks. Implications for calibration of production rates},

author = {I. Schimmelpfennig and L. Benedetti and R. Finkel and R. Pik and P. H. Blard and D. Bourles and P. Burnard and A. Williams},

doi = {10.1016/j.quageo.2009.06.003},

issn = {1871-1014},

year  = {2009},

date = {2009-01-01},

journal = {Quaternary Geochronology},

volume = {4},

number = {6},

pages = {441--461},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blard+Pik2008,

title = {An alternative isochron method for measuring cosmogenic He-3 in lava flows},

author = {P. H. Blard and R. Pik},

doi = {10.1016/j.chemgeo.2008.02.004},

year  = {2008},

date = {2008-01-01},

journal = {Chemical Geology},

volume = {251},

number = {1-4},

pages = {20--32},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blard_etal2007,

title = {Persistence of full glacial conditions in the central Pacific until 15,000 years ago},

author = {P. H. Blard and J. Lav\'{e} and R. Pik and P. Wagnon and D. Bourl`es},

doi = {10.1038/nature06142},

year  = {2007},

date = {2007-01-01},

journal = {Nature},

volume = {449},

number = {7162},

pages = {585--591},

keywords = {},

pubstate = {published},

tppubtype = {article}

}