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Clay minerals in delta deposits and organic preservation potential on Mars

Ehlmann, Bethany L. and Mustard, John F. and Fassett, Caleb I. and Schon, Samuel C. and Head, James W., III and Des Marais, David J. and Grant, John A. and Murchie, Scott L. (2008) Clay minerals in delta deposits and organic preservation potential on Mars. Nature Geoscience, 1 (6). pp. 355-358. ISSN 1752-0894. doi:10.1038/ngeo207.

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Clay-rich sedimentary deposits are often sites of organic matter preservation and have therefore been sought in Mars exploration. However, regional deposits of hydrous minerals, including phyllosilicates and sulphates are not typically associated with valley networks and layered sediments that provide geomorphic evidence of surface water transport on early Mars. The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) has recently identified phyllosilicates within three lake basins with fans or deltas that indicate sustained sediment deposition: Eberswalde crater Holden crater and Jezero crater. Here we use high-resolution data from the Mars Reconnaissance Orbiter (MRO) to identify clay-rich fluvial–lacustrine sediments within Jezero crater, which has a diameter of 45 km. The crater is an open lake basin on Mars with sedimentary deposits of hydrous minerals sourced from a smectite-rich catchment in the Nili Fossae region. We find that the two deltas and the lowest observed stratigraphic layer within the crater host iron–magnesium smectite clay. Jezero crater holds sediments that record multiple episodes of aqueous activity on early Mars. We suggest that this depositional setting and the smectite mineralogy make these deltaic deposits well suited for the sequestration and preservation of organic material.

Item Type:Article
Related URLs:
URLURL TypeDescription
Ehlmann, Bethany L.0000-0002-2745-3240
Fassett, Caleb I.0000-0001-9155-3804
Head, James W., III0000-0003-2013-560X
Grant, John A.0000-0001-8276-1281
Murchie, Scott L.0000-0002-1616-8751
Additional Information:© 2008 Nature Publishing Group, a division of Macmillan Publishers Limited. Received 11 January 2008; accepted 24 April 2008; published 18 May 2008. Special thanks go to the entire MRO team: without their ongoing efforts, these new discoveries would not be possible.We especially recognize the efforts of the CTX and HiRISE teams for coordinated observations with CRISM. Special thanks to Gregg Swayze for numerous discussions on interpreting CRISM spectra from the Nili Fossae region. The comments of reviewers Vincent Chevrier and Victor Baker helped improve this manuscript.
Issue or Number:6
Record Number:CaltechAUTHORS:20121017-113424651
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Official Citation:Ehlmann, B. L., J. F. Mustard, et al. (2008). "Clay minerals in delta deposits and organic preservation potential on Mars." Nature Geosci 1(6): 355-358.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34950
Deposited On:17 Oct 2012 22:01
Last Modified:09 Nov 2021 23:11

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