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An in-situ record of major environmental transitions on early Mars at Northeast Syrtis Major

Ehlmann, Bethany L. and Mustard, John F. (2012) An in-situ record of major environmental transitions on early Mars at Northeast Syrtis Major. Geophysical Research Letters, 39 (L11). Art. No. L11202. ISSN 0094-8276.

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The Noachian-Hesperian transition on Mars was a period marked by changes in volcanic processes and styles of aqueous alteration. Understanding the timing and nature of environmental change requires the exploration of units recording both sets of processes. Herein, we report the compositional stratigraphy of distinctive Noachian to Hesperian units along the northeastern margin of the Syrtis Major volcanic flows. A layered, polyhydrated sulfate-bearing unit with jarosite ridges has been discovered beneath the Syrtis Major lava flows and above the regionally-extensive stratigraphy of Noachian plains units reported previously. Sequential clay-, carbonate-, and sulfate-bearing units formed in-situ and record a transition from alkaline pH to acidic pH waters. The sequence is chronologically bookended by the Isidis impact and Syrtis Major flows, and is one of the most temporally-constrained and well-preserved stratigraphic sections from early Mars available for landed exploration.

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Ehlmann, Bethany L.0000-0002-2745-3240
Additional Information:© 2012 American Geophysical Union. Received 3 March 2012; revised 6 May 2012; accepted 8 May 2012; published 6 June 2012. The authors thank R. Harvey for initial discussions about the timing of processes related to volcanic emplacement and J.R. Skok for discussions on stratigraphy. The Editor thanks Harold Clenet and an anonymous reviewer for assisting in the evaluation of this paper.
Subject Keywords:Mars; aqueous alteration; carbonates; clay minerals; stratigraphy; sulfates
Issue or Number:L11
Record Number:CaltechAUTHORS:20121012-095415095
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Official Citation:Ehlmann, B. L., and J. F. Mustard (2012), An in-situ record of major environmental transitions on early Mars at Northeast Syrtis Major, Geophys. Res. Lett., 39, L11202, doi:10.1029/ 2012GL051594
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34868
Deposited By: Tony Diaz
Deposited On:12 Oct 2012 18:26
Last Modified:09 Mar 2020 13:18

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