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Paleosols and paleoenvironments of early Mars

Gregory J. Retallack
Paleosols and paleoenvironments of early Mars
Geology (Boulder) (September 2014) 42 (9): 755-758


Fluviolacustrine sediments filling Gale Crater on Mars show two levels of former exposure and weathering that provide new insights into late Noachian (3.7 + or - 0.3 Ga) paleoenvironments of Mars. Diagnostic features of the two successive paleosols in the Sheepbed member include complex cracking patterns of surface dilation (peds and cutans), a clayey surface (A horizon), deep sand-filled cracks with vertical lamination (sand wedges), and replacive sulfate nodules aggregated into distinct bands (gypsic By horizon) above bedded sandy layers (sedimentary C horizon). Shallow gypsic horizon, periglacial sand wedges, and limited chemical weathering are evidence of a hyperarid frigid paleoclimate, and this alternated with wetter conditions for the lacustrine parent materials in Gale Crater during the late Noachian. Depletion of phosphorus, vesicular structure, and replacive gypsic horizons of these Martian paleosols are features of habitable microbial earth soils on Earth, and encourage further search for definitive evidence of early life on Mars.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 42
Serial Issue: 9
Title: Paleosols and paleoenvironments of early Mars
Affiliation: University of Oregon, Department of Geological Sciences, Eugene, OR, United States
Pages: 755-758
Published: 201409
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 28
Accession Number: 2014-082773
Categories: Extraterrestrial geology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2014275
Illustration Description: illus. incl. sketch map
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201443
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