A Large New Crater Exposes the Limits of Water Ice on Mars. Issue 2 (23rd January 2023)

• Record Type: Journal Article
• Authors: Dundas, Colin M.; Mellon, Michael T.; Posiolova, Liliya V.; Miljković, Katarina; Collins, Gareth S.; Tornabene, Livio L.; Rangarajan, Vidhya Ganesh; Golombek, Matthew P.; Warner, Nicholas H.; Daubar, Ingrid J.; Byrne, Shane; McEwen, Alfred S.; Seelos, Kimberly D.; Viola, Donna; Bramson, Ali M.; Speth, Gunnar
• Is Part Of: Geophysical research letters. Volume 50:Issue 2(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-01-23
• Subjects: Mars -- ice -- subsurface -- midlatitudes -- climate; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2022GL100747
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Water ice in the Martian mid‐latitudes has advanced and retreated in response to variations in the planet's orbit, obliquity, and climate. A 150 m‐diameter new impact crater near 35°N provides the lowest‐latitude impact exposure of subsurface ice on Mars. This is the largest known ice‐exposing crater and provides key constraints on Martian climate history. This crater indicates a regional, relatively pure ice deposit that is unstable and has nearly vanished. In the past, this deposit may have been tens of meters thick and extended equatorward of 35°N. We infer that it is overlain by pore ice emplaced during temporary stable intervals, due to recent climate variability. The marginal survival of ice here suggests that it is near the edge of shallow ice that regularly exchanges with the atmosphere. Plain Language Summary: A 150 m‐diameter new impact crater on Mars exposes water ice, constraining the nature of past and present ice sheets and paleoclimate. The past climate has varied, gradually removing a massive ice deposit that has nearly been lost at 35°N but survives at higher latitude. Key Points: Water ice is exposed in a 150 m‐diameter new impact crater near 35°N on Mars The ice includes both massive ice and a covering layer of pore ice This ice marks the southern margin of remaining ice deposits from high‐obliquity periods