Learn More
3 Highlights  In situ calcification (aragonite) of a 3.3 Ga microbial biofilm  Calcification probably due to the activities of a photosynthetic consortium of microorganisms within the biofilm including heterotrophic sulphur reducing bacteria  Preservation of the metastable carbonate phase by the organic matrix and secondary silicification  Oldest known(More)
Primitive interplanetary dust is expected to contain the earliest solar system components, including minerals and organic matter. We have recovered, from central Antarctic snow, ultracarbonaceous micrometeorites whose organic matter contains extreme deuterium (D) excesses (10 to 30 times terrestrial values), extending over hundreds of square micrometers. We(More)
Introduction: The Kaidun meteorite has been described as a complex polymict breccia. It contains clasts spanning a wide range of achondrite and chondrite groups [1]. The chondritic lithologies all contain carbonates, derived from aqueous alteration. In this work, we used a NanoSims to characterize 53 Mn-53 Cr internal isochrons on 3 individual dolomite(More)
To evaluate the isotopic composition of the solar nebula from which the planets formed, the relation between isotopes measured in the solar wind and on the Sun's surface needs to be known. The Genesis Discovery mission returned independent samples of three types of solar wind produced by different solar processes that provide a check on possible isotopic(More)
Pristine meteoritic materials carry light element isotopic fractionations that constrain physiochemical conditions during solar system formation. Here we report the discovery of a unique xenolith in the metal-rich chondrite Isheyevo. Its fine-grained, highly pristine mineralogy has similarity with interplanetary dust particles (IDPs), but the volume of the(More)
In the nascent solar system, primitive organic matter was a major contributor of volatile elements to planetary bodies, and could have played a key role in the development of the biosphere. However, the origin of primitive organics is poorly understood. Most scenarios advocate cold synthesis in the interstellar medium or in the outer solar system. Here, we(More)
Introduction: Most of the organic carbon in Carbonaceous Chondrites (CC) is in the form of Insoluble Organic Matter (IOM). Isotopically, the IOM in CC appears to be highly un-equilibrated: discrete H and N isotopic anomalies-the so-called hotspots-with δ values up to +19400‰ and +1770‰, respectively, are embedded in the bulk IOM, which has average(More)
Introduction: Apart from [1], the insoluble organic matter (IOM) isolated from meteorites has been mostly studied in car-bonaceous chondrites (CCs) during the last decade. Numerous details were obtained concerning the macromolecular structure or the isotopic composition of the IOM. In the present study, HF-HCl treatments previously improved on carbonaceous(More)