Amapari marker band metal‐enrichments: potential mechanisms and implications for surface and subsurface water and weathering in Gale crater
Author(s)
Type
Journal Article
Abstract
NASA's Curiosity rover is exploring a 5 km tall sedimentary mound that is hypothesized to record the transition from a warm and wet (phyllosilicate-rich) to a cold and drier (sulfate-rich) Mars. Evidence of magnesium sulfate-bearing rock has shown that Curiosity has crossed through this phyllosilicate-sulfate transition. Recently, Curiosity arrived at the Amapari Marker Band, a darker, indurated unit that can be traced laterally for tens of kilometers in orbiter images. Here, Curiosity found evidence for a very broad lake, and bedforms interpreted as wave-ripple laminated sedimentary rock that likely was deposited in shallow water in the explored location, before becoming a deeper lake. These rocks are enriched in Fe, Mn, and Zn which has major implications for groundwater paleohydrology in Gale crater. Three formation hypotheses are considered: concretion formation during early diagenetic alteration of shallow lake sediments, laterization or leaching of the sediments, and addition of Fe, Mn, and Zn by a mildly acidic and reducing groundwater interacting with a redox and/or pH front in a stratified lake. The preferred interpretation of the metal enrichments within the Amapari Marker band sedimentary rocks is that they formed in a shallow water environment at a redox and/or pH front within the ripple unit, which drove precipitation and concentration of metals. If the enrichments are due to groundwater alteration, these processes could link subsurface and surface environments. Water and the presence of high amounts of redox sensitive elements and other metals are favorable indicators for habitability.
Date Issued
2026-04-01
Date Acceptance
2026-03-14
Citation
Journal of Geophysical Research: Planets, 2026, 131 (4)
ISSN
2169-9097
Publisher
American Geophysical Union (AGU)
Journal / Book Title
Journal of Geophysical Research: Planets
Volume
131
Issue
4
Copyright Statement
© 2026. Jet Propulsion Laboratory, California Institute of Technology. Government sponsorship acknowledged, Triad National Security, LLC and The Author(s). This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Publication Status
Published
Article Number
e2025JE009153
Date Publish Online
2026-04-13