Compositional stratigraphy of clay-bearing layered deposits at Mawrth Vallis, Mars
Article first published online: 21 JUN 2008
Copyright 2008 by the American Geophysical Union.
Geophysical Research Letters
Volume 35, Issue 12, June 2008
How to Cite
2008), Compositional stratigraphy of clay-bearing layered deposits at Mawrth Vallis, Mars, Geophys. Res. Lett., 35, L12202, doi:10.1029/2008GL034385., , , , and (
- Issue published online: 21 JUN 2008
- Article first published online: 21 JUN 2008
- Manuscript Accepted: 19 MAY 2008
- Manuscript Revised: 15 MAY 2008
- Manuscript Received: 22 APR 2008
 Phyllosilicates have previously been detected in layered outcrops in and around the Martian outflow channel Mawrth Vallis. CRISM spectra of these outcrops exhibit features diagnostic of kaolinite, montmorillonite, and Fe/Mg-rich smectites, along with crystalline ferric oxide minerals such as hematite. These minerals occur in distinct stratigraphic horizons, implying changing environmental conditions and/or a variable sediment source for these layered deposits. Similar stratigraphic sequences occur on both sides of the outflow channel and on its floor, with Al-clay-bearing layers typically overlying Fe/Mg-clay-bearing layers. This pattern, combined with layer geometries measured using topographic data from HiRISE and HRSC, suggests that the Al-clay-bearing horizons at Mawrth Vallis postdate the outflow channel and may represent a later sedimentary or altered pyroclastic deposit that drapes the topography.