Lava flows at Arsia Mons, Mars: Insights from a graben imaged by HiRISE |
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Authors: | Peter J. Mouginis-Mark Scott K. Rowland |
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Affiliation: | a Hawaii Institute of Geophysics and Planetology, University of Hawaii, 1680 East-West Road, POST Room 504, Honolulu, HI 96822, USA b Department Geology and Geophysics, University of Hawaii, Honolulu, HI 96822, USA |
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Abstract: | HiRISE has imaged a graben wall on the western flank of Arsia Mons volcano, Mars. This graben is ∼3×16 km in plan-view size and is oriented almost perpendicular to the general volcano slope. We have identified 1318 individual sub-horizontal layers, which we interpret to be lava flows, in the 885 m high, nearly vertical, eastern wall of this graben. The average and median outcrop widths of each layer are 149 and 85 m, respectively. No layers extend >1.72 km across the width of the section, arguing against these being either areally-extensive ash or paleo-glacial deposits, which has implications for the reoccurrence interval of glacial events and/or the long-term magma production rate of the volcano. Measurements (N=118) made at a 100-m spacing across the width of the section reveal that there are, on average, 17.3 layers at each location. This implies an average layer thickness of ∼51 m. Locally, however, as many as 7 layers can be counted within a 70 m-high part of the section, implying, if these layers are indeed lava flows, that Arsia Mons occasionally erupted flows that were only ∼10 m thick. |
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Keywords: | Mars Mars, surface Volcanism |
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