¹E. A. MacLagan,^1,2E. L. Walton,¹C. D. K. Herd,¹B. Rivard
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13388]
¹Department of Earth and Atmospheric Sciences, University of Alberta, 1-26 Earth Sciences Building, Edmonton, Alberta T6G 2E3, Canada
²Department of Physical Sciences, MacEwan University, City Centre Campus, 10700 104 Ave, Edmonton, Alberta T5J 4S2, Canada
Published by Arrangement with John Wiley and Sons

Hyperspectral imaging can be used to rapidly identify and map the spatial
distributions of many minerals. Here, hyperspectral mapping in three wavelength regions(visible and near-infrared, shortwave infrared, and thermal infrared) was applied to drill cores (ST001, ST002, and ST003) penetrating a continuous sequence of crater-fill breccias from the Steen River impact structure in Alberta, Canada. The combined data sets reveal distinct mineralogical layering, with breccias derived predominantly from sedimentary rocks overlying those derived from granitic basement. This stratigraphy demonstrates that the
breccias were not appreciably disturbed following deposition, which is inconsistent with formation models of similar breccias (suevites) by explosive impact melt–fluid interaction. At Steen River, volatiles from sedimentary target rocks were an inherent part of forming these enigmatic breccias. Approximately three quarters of terrestrial impact structures contain sedimentary target rocks; therefore, the role of volatiles in producing so-called
suevitic breccias may be more widespread than previously realized. The hyperspectral maps, specifically within the SWIR wavelength region, also delineate minerals associated with postimpact hydrothermal activity, including ammoniated clay and feldspar minerals not detectable using traditional techniques. These nitrogen-bearing minerals may have originated from microbial processes, associated with oil- and gas-producing units in the
crater vicinity. Such minerals may have important implications for the production of habitable environments by impact-induced hydrothermal activity on Earth and Mars.

¹B.L. Carrier,¹W.J. Abbey,¹L.W. Beegle,¹R. Bhartia,¹Y. Liu
Journal of Geophysical Research, Planets (in Press) Link to Article [https://doi.org/10.1029/2018JE005758]
¹Jet Propulsion Laboratory, California Institute of Technology
Published by arrangement with John Wiley & Sons

The effects of radiation on the survivability of key biosignatures are a driving factor in exploration strategies throughout the solar system. Ultraviolet (UV) radiation, especially shorter wavelength UVC radiation, is known to be damaging to organisms and to potential organic biosignatures; however the interaction of UV radiation with minerals and rocks is not well understood. Constraining the survivability of organics and generation of habitable zones requires assessment of physical parameters such as penetration depth of UV photons. This type of information helps to identify to what extent rocks and minerals can provide effective shielding against UV radiation and is especially important on Mars where the surface chemistry is more oxidizing and the radiation environment is more extreme than on Earth. Using pressed pellets of natural gypsum, kaolinite, Mars simulant basalt and welded tuff, we measured the spectral transmittance of each in the wavelength range of 220‐400 nm. Although transmittance drops off quickly with depth, detectable levels of UV can penetrate >500 μm in each material. Each substrate allowed higher transmittance of UVC radiation than of longer wavelength UVA/B radiation, possibly as a result of surface reflectance and internal scattering properties. This could result in increased subsurface photolysis of organic compounds and biosignatures. We have used the transmittance data collected herein to constrain the lifetimes of several organic molecules in the Martian subsurface. These results will also have implications for organic analyses to be conducted by Mars 2020, and could be used to better constrain the SHERLOC/Mars 2020 interrogation volume.

¹Makino, Y.,²Kuroki, Y.,¹Hirata, T.
Journal of Analytical Atomic Spectroscopy 34, 1794-1799 Link to Article [DOI: 10.1039/c9ja00181f]
¹Geochemistry Research Center, School of Science, University of Tokyo Hongo, Tokyo, 113-0033, Japan
²Thermo Fisher Scientific K.K., Tokyo, 108-0023, Japan

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