HR: 1340h
AN: P23A-0178    [Abstracts]
TI: Basaltic "Plains-Style" Volcanism in Arizona as a Possible Analogue to Mars
AU: * Cave, S R
EM: shelby.cave@asu.edu
AF: Department of Geological Sciences, Arizona State University Box 871404, Tempe, AZ 85287-1404 United States
AB: The Sentinel Plains lava field and associated small shields, collectively referred to as the Sentinel-Arlington Volcanic Field (SAVF), are located ~75 km southwest of Phoenix, Arizona. The SAVF is composed of Pliocene-Pleistocene alkali olivine basaltic lava flows and covers ~600 km². It consists of 20+ eruptive centers ranging from 4-6 km in diameter and 30-200 m in height. The two northeastern isolated small shields have volumes ranging from 0.3-0.4 km³ and median slopes ranging from 1.8°-2.5°. Preliminary results from geologic mapping and remote sensing data indicate that the volumes of the remaining SAVF eruptive centers are comparative to these, but that the median slopes within the contiguous lava field are possibly lower due to embayment of eruptive centers. The SAVF lies on the eastern terminus of the Gila River Low, a northeast-trending graben, and a series of normal faults cuts across the surrounding terrain. This indicates that the loci of the SAVF eruptive centers could be controlled by structural trends. The SAVF erupted near the Gila River channel, damming and diverting the river at least once and potentially several times, forming small ephemeral lakes. The SAVF basal contact is ~30 m above the present-day surface. The SAVF is similar in morphology, composition and eruptive style to the Snake River Plain in Idaho and the Cima Volcanic Field in California, which have been used as planetary analogues. The SAVF is also a good potential analogue to small-volume effusive volcanic centers on Mars, such as those seen the southern flank of Pavonis Mons in Mars Express High Resolution Stereo Camera (HRSC) images and Thermal Emission Imaging System (THEMIS) visible images, for several reasons. The SAVF lavas are lightly mantled by aeolian dust and basaltic rubble, similar to martian surfaces. The SAVF also represent basaltic plains-style volcanism, an emplacement style of volcanism intermediate between classic flood volcanism and large shield-building volcanism which has been previously recognized on Mars.
DE: 8415 Intra-plate processes (1033, 3615)
DE: 8425 Effusive volcanism
DE: 8450 Planetary volcanism (5480, 6063, 8148)
DE: 8486 Field relationships (1090, 3690)
SC: Planetary Sciences [P]
MN: Fall Meeting 2005