T156 Geomorphology and Landscape Evolution of Mars

Tuesday, 11 October 2022
8:00 AM - 12:00 PM
501

FURTHER EVIDENCE FOR ANCIENT EXPLOSIVE VOLCANISM IN NORTHERN ARABIA TERRA, MARS

Paper number: T156-5
Program: Technical Sessions
Time: 8:55 AM – 9:10 AM

Authors

Abstract

Over 70% of the Martian crust has been resurfaced by basaltic volcanism, with a significant fraction not accounted for by recognized volcanic sources. This discrepancy has motivated searches to find other sources, such as in the Arabia Terra region, hypothesized by [1] to contain ancient volcanic calderas that were previously thought to be impact craters. By using spectroscopy, we can determine the composition of the region surrounding the proposed volcanoes. Finding minerals consistent with altered volcanic material, as recently reported by [2] across a broad swath of northern Mars, would support the hypothesis of ancient volcanoes in Arabia Terra.

To identify the minerology of Arabia Terra, we analyzed images from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), a visible/near-infrared hyperspectral mapping instrument aboard the Mars Reconnaissance Orbiter. We searched for several mineral types known to occur in altered volcaniclastic materials, including hydrated/opaline silica, smectites, zeolites, and sulfates. We have identified several new locations with silica deposits near the proposed volcanoes, with some occurring in or near depressions that could be previously unrecognized calderas. Spectral analysis of the silica deposits is ongoing, as their detailed characteristics can help to elucidate mode(s) of origin and subsequent alteration. Additional planned work will incorporate complementary datasets including high-resolution imagery and topography, and thermal inertia to assess the deposits’ consistency with a volcaniclastic origin.

These additional examples of hydrated silica immediately surrounding proposed calderas supports the claims that there could have been explosive volcanoes in the Arabia Terra region of Mars. The presence of large, ancient volcanoes in Arabia Terra has major implications for Mars’ geological and atmospheric history, subsurface environments, and thus the history of habitability on Mars.

[1] Michalski J. R. & Bleacher J. E. (2013), Nature 502, 47-52. [2] Whelley P. et al. (2021), GRL 48, e2021GL094109.

Geological Society of America Abstracts with Programs. Vol. 54, No. 6

doi: 10.1130/abs/2022AM-380207

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