HR: 17:05h
AN: P34A-04    [Abstracts]
TI: Morphology and Emplacement of Long Lava Flows in the Tharsis Volcanic Province, Mars
AU: * Garry, W B
EM: garryw@si.edu
AF: Center for Earth and Planetary Studies, Smithsonian Institution, National Air and Space Museum MRC 315 PO Box 37012, Washington, DC 20013, United States
AU: Zimbelman, J R
EM: zimbelmanj@si.edu
AF: Center for Earth and Planetary Studies, Smithsonian Institution, National Air and Space Museum MRC 315 PO Box 37012, Washington, DC 20013, United States
AB: Lava flows, 10's to 100's of kilometers in length, dominate the lower plains surrounding the Tharsis Montes volcanoes (Ascraeus Mons, Pavonis Mons, and Arsia Mons) on Mars. An analysis of the morphology and emplacement of a 690-km-long lava flow on the southwest perimeter of Ascraeus Mons indicates that effusion rates on the order of 10⁴ m³ s^-1 and eruption durations of 3 to 7 Earth-months are needed to emplace a flow of this scale. We will present an analysis of the morphology and emplacement, including effusion rates, eruption durations, and style of flow (e.g. channeled or non-channeled) for 10 lava flows with flow lengths traceable for >100 km in the Tharsis Montes region, Mars identified in a mosaic of Thermal Infrared Imaging System (THEMIS) infrared images (256 m/pixel). The source areas for these flows are typically obscured, but the center-lines of the flows trend back toward the aprons on the northeast and southern flanks of each of the volcanoes. Lava flows in Hawaii and New Mexico serve as terrestrial analogs for the lava flows we are studying on Mars. We have combined mapping of Ikonos images (2 m/pixel) with Differential Global Positioning System (DGPS) transects to interpret the emplacement of channeled a'a flow from the 1907 eruption on Mauna Loa volcano, Hawaii. Downstream changes in flow morphology are similar between the 1907 Mauna Loa flow and the ~690-km-long lava flow from Ascraeus Mons, though the 1907 flow has a shorter eruption duration, flow length, and lower calculated eruption rate. We will also present a preliminary analysis of research on a lava flow in New Mexico as an analog for non-channeled lava flows. Additional studies of lava flows >100 km long in the Tharsis region will constrain eruption parameters along the lower plains and provide insight into late-stage eruption periods of these three large volcanoes.
DE: 5480 Volcanism (6063, 8148, 8450)
DE: 8414 Eruption mechanisms and flow emplacement
DE: 8425 Effusive volcanism
DE: 8429 Lava rheology and morphology
SC: Planetary Sciences [P]
MN: 2007 Joint Assembly