Bernard Marty

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The Genesis mission sampled solar wind ions to document the elemental and isotopic compositions of the Sun and, by inference, of the protosolar nebula. Nitrogen was a key target element because the extent and origin of its isotopic variations in solar system materials remain unknown. Isotopic analysis of a Genesis Solar Wind Concentrator target material(More)
Estimates of CO emissions at spreading centres, convergent margins, and plumes have been reviewed and upgraded 2 using observed CO r He ratios in magmatic volatiles, He content estimates in the magmatic sources, and magma 2 emplacement rates in the different tectonic settings. The effect of volatile fractionation during magma degassing, Ž . investigated(More)
Ion microprobe analyses show that solar wind nitrogen associated with solar wind hydrogen implanted in the first tens of nanometers of lunar regolith grains is depleted in 15N by at least 24% relative to terrestrial atmosphere, whereas a nonsolar component associated with deuterium-rich hydrogen, detected in silicon-bearing coatings at the surface of some(More)
Archean rocks may provide a record of early Earth environments. However, such rocks have often been metamorphosed by high pressure and temperature, which can overprint the signatures of their original formation. Here, we show that the early Archean banded rocks from Isua, Akilia, and Innersuartuut, Greenland, are enriched in heavy iron isotopes by 0.1 to(More)
The Lunar cratering record is consistent with the occurrence of a late heavy bombardment (LHB), which marked the end of terrestrial planet accretion 3.8 billion years ago. However, clear evidence of a LHB on Earth has not yet been identified. Based on a volatile budget of the terrestrial mantle, the atmosphere and hydrosphere we propose that the LHB did(More)
Understanding the atmosphere's composition during the Archean eon is fundamental to unraveling ancient environmental conditions. We show from the analysis of nitrogen and argon isotopes in fluid inclusions trapped in 3.0- to 3.5-billion-year-old hydrothermal quartz that the partial pressure of N2 of the Archean atmosphere was lower than 1.1 bar, possibly as(More)
To constrain further the Mg isotopic composition of the Earth and chondrites, and investigate the behavior of Mg isotopes during planetary formation and magmatic processes, we report high-precision (±0.06& on dMg and ±0.07& on dMg, 2SD) analyses of Mg isotopes for (1) 47 mid-ocean ridge basalts covering global major ridge segments and spanning a broad range(More)
Noble metals and gases are very sensitive to the late accretion to the Earth of asteroids and comets. We present mass balance arguments based on these elements that indicate that 0.7 − 2.7 × 10 kg of extraterrestrial bodies struck the Earth after core formation and that comets comprised less than 10 by mass of the impacting population. These results imply(More)