Open AccessEvidence of phyllosilicates in Wooly Patch, an altered rock encountered at West Spur, Columbia Hills, by the Spirit rover in Gusev crater, Mars
Author(s) -
Wang Alian,
Korotev Randy L.,
Jolliff Bradley L.,
Haskin Larry A.,
Crumpler Larry,
Farrand William H.,
Herkenhoff Ken E.,
de Souza Paulo,
Kusack Alastair G.,
Hurowitz Joel A.,
Tosca Nicholas J.
Publication year - 2006
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2005je002516
Subject(s) - geology , kaolinite , noachian , outcrop , impact crater , mars exploration program , basalt , mineralogy , geochemistry , chlorite , weathering , martian , astrobiology , quartz , paleontology , physics
On its traverse to Columbia Hills, the Mars Exploration Rover Spirit investigated an outcrop designated “Wooly Patch” that exhibited morphological, mineralogical, and geochemical characteristics at the extreme ends of ranges observed among rocks studied at West Spur, a westward projecting salient near the foot of the Columbia Hills, Gusev crater. The major‐element composition and Fe‐mineralogy, as determined by the Alpha‐Particle X‐ray Spectrometer and Mössbauer Spectrometer, are inconsistent with any reasonable assemblage of basaltic minerals in that there is an excess of Si and Al. The combined data are best explained by the presence of 14–17% phyllosilicate minerals. Phyllosilicates that account for the composition and cation ratios include members of the kaolinite, serpentine, chlorite, and septechlorite groups. The potential existence of kaolinite‐type Al‐rich phyllosilicates within the Wooly Patch outcrop suggests a mildly acidic environment (pH 4–6) in the past and an open hydrologic system with good drainage conditions in the environment where these rocks were altered.