Anomalous Phyllosilicate‐Bearing Outcrops South of Coprates Chasma: A Study of Possible Emplacement Mechanisms

Author(s)

Debra L. Buczkowski, Kimberly D. Seelos, Christina E. Viviano, Scott L. Murchie, Frank P. Seelos, Eric Malaret, and Christopher Hash

Publication Year

2019

Journal

Journal of Geophysical Research - Planets 124:

DOI

10.1029/2019JE006043

Description

The formation of widespread phyllosilicate‐bearing near‐surface layers on Mars has often been attributed to pedogenesis, a process of weathering basaltic soils by continued exposure to meteoric water percolating down from the surface, which can result in layers of aluminum phyllosilicates forming over layers of iron‐magnesium phyllosilicates. We present evidence of an Fe/Mg‐smectite bearing layer stratigraphically above Al‐phyllosilicates in three circular features to the south of Coprates Chasma, suggesting that some process other than, or in addition to, a single pedogenic sequence must have been involved. A review of several formation mechanisms shows that all models require multiple episodes of aqueous alteration. In addition, only by invoking groundwater alteration in conjunction with pedogenesis can we reconcile the stratigraphic pattern of altered material exposed by these features.

Files

No files
Uploaded by buczkdl1 on June 22, 2021, 7:30 p.m.
Last modified June 22, 2021, 7:37 p.m.