Compositional stratigraphy of clay-bearing layered deposits at Mawrth Vallis, Mars

Wray, J. J.; Ehlmann, B. L.; Squyres, S. W.; Mustard, J. F.; Kirk, R. L.

Abstract:

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. Copyright 2008 by the American Geophysical Union.

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Article

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70000490

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Wray, J. J.; Ehlmann, B. L.; Squyres, S. W.; Mustard, J. F.; Kirk, R. L.

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English

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Geophysical Research Letters

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Compositional stratigraphy of clay-bearing layered deposits at Mawrth Vallis, Mars; 2008; Article; Journal; Geophysical Research Letters; Wray, J. J.; Ehlmann, B. L.; Squyres, S. W.; Mustard, J. F.; Kirk, R. L.