Modal mineralogy of CI and CI-like chondrites by X-ray diffraction

The CI chondrites are some of the most hydrated meteorites available to study, making them ideal samples with which to investigate aqueous processes in the early Solar System. Here, we have used position-sensitive-detector X-ray diffraction (PSD-XRD) to quantify the abundance of minerals in bulk samples of the CI chondrite falls Alais, Orgueil and Ivuna, and the Antarctic CI-like chondrites Y-82162 and Y-980115. We find that Alais, Orgueil and Ivuna are dominated by a mixed serpentine/saponite phyllosilicate (81–84 vol%), plus minor magnetite (6–10%), sulphides (4–7%) and carbonates (<3%). This reflects an extended period of aqueous alteration and the near-complete transformation of anhydrous phases into a secondary mineral assemblage. The similarity in total abundance of phyllosilicate suggests that the CI chondrites all experienced the same degree of aqueous alteration on the parent body. In contrast, Y-82162 contains a highly disordered serpentine/saponite phyllosilicate (68 vol%), sulphide (19%), olivine (11%) and magnetite (2%). This mineralogy is distinct from that of the CI chondrites, attesting to both a different starting mineralogy and alteration history. The structure and relatively low abundance of the phyllosilicate, and the high abundance of olivine, are consistent with previous observations that Y-82162 represents CI-like material that following aqueous alteration suffered thermal metamorphism at temperatures >500 °C. Similarly, Y-980115 contains disordered serpentine/saponite (71 vol%), sulphide (19%), olivine (8%) and magnetite (2%), confirming that it too is a thermally metamorphosed CI-like chondrite. We suggest that the CI-like chondrites are derived from a different parent body than the CI chondrites, which underwent short-lived thermal metamorphism due to impacts and/or solar radiation

Managing technological uncertainty in science incubation:A prospective sensemaking perspective

This paper focuses on the adaption challenge that confronts the top management team (TMT) of science incubators in situations of substantial technological uncertainty. To do that, we draw on the three-year longitudinal analysis of a major bioscience catalyst in the UK. Through the lens of ‘prospective sensemaking’, we follow the TMT as they work with stakeholders in their ecosystem to make sense of a significant technological shift: the convergence of life sciences, IT and other sciences in the health care environment. Our analysis reveals how prospective sensemaking resulted in the launch of a new strategy to exploit these emerging opportunities. However, stakeholders’ increasingly fragmented interpretation of the term convergence and the anticipation of legitimacy challenges in the wider ecosystem resulted in the repositioning of the incubator. Our findings contribute to extant research on science incubation. In particular, the paper sheds light on the complex interactions of incubator TMT’s with stakeholders in situations of technological change and uncertainty. Moreover, responding to technological change does not only affect the structural conditions of an incubator. Rather, it may also require changes to the positioning of the incubator in order to maintain legitimacy in the wider ecosystem. The paper also suggests managerial as well as policy level implications

Fatty acid preservation in mars-analogous rock samples and detection with the tmah wet chemistry experiment on the sample analysis at Mars (sam) instrument

International audienc

Life Underground: Investigating Microbial Communities and Their Biomarkers in Mars-Analog Lava Tubes at Craters of the Moon National Monument and Preserve

Craters of the Moon National Monument and Preserve (CotM) is a strong terrestrial analog for lava tube formations on Mars. The commonality of its basalt composition to Martian lava tubes makes it especially useful for probing how interactions between water, rock, and life have developed over time, and what traces of these microbial communities may be detectable by current flight-capable instrumentation. Our investigations found that secondary mineral deposits within these caves contain a range of underlying compositions that support diverse and active microbial communities. Examining the taxonomy, activity, and metabolic potential of these communities revealed largely heterotrophic life strategies supported by contributions from chemolithoautotrophs that facilitate key elemental cycles. Finally, traces of these microbial communities were detectable by flight-capable pyrolysis and wet chemistry gas chromatography-mass spectrometry methods comparable to those employed by the Sample Analysis at Mars (SAM) instrument aboard the Curiosity rover and the Mars Organic Molecule Analyzer (MOMA) on the upcoming Rosalind Franklin rover. Using a suite of methods for chemical derivatization of organic compounds is beneficial for resolving the greatest variety of biosignatures. Tetramethylammonium hydroxide (TMAH), for example, allowed for optimal resolution of long chain fatty acids. Taken together, these results have implications for the direction of mass spectrometry as a tool for biosignature detection on Mars, as well as informing the selection of sampling sites that could potentially host biosignatures. © 2022. American Geophysical Union. All Rights Reserved.6 month embargo; first published: 03 November 2022This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]