HR: 1340h
AN: P13A-1042    [Abstracts]
TI: Lava Flows in Pickering Crater, Mars: Details From Mars Global Surveyor and Mars Odyssey Datasets Constrain Complex Lava Flooding History
AU: * Caprarelli, G
EM: Graziella.Caprarelli@uts.edu.au
AF: University of Technology Sydney, Dept Environmental Sci, PO Box 123, Broadway, NSW 2007, Australia
AB: Pickering Crater is an approximately 130 km diameter impact crater on the surface of Mars. Its central peak is located at approximately 133 degrees W - 33 degrees S. The crater lies about 1500 km SW of Arsia Mons, the oldest of the Tharsis Plateau volcanoes. The crater rim has undergone substantial erosion by meteoritic impact and mass wasting. The NW portion of the rim is breached. The crater has been infilled by products of erosion and by lavas related to the activity of Arsia Mons. Mars Global Surveyor Mars Orbiter Laser Altimer (MOLA) and Mars Orbiter Camera (MOC) wide and narrow angle (WA, NA) datasets, Mars Odyssey Thermal Emission Imaging System (THEMIS) visual images, and geographic information systems techniques, were used to observe and interpret geological details in and around Pickering Crater. Morphometric analysis suggests that the crater is covered by about 1.6 km thick rocks and sediments. The most surficial layers of this cover comprise lava flows and recent aeolian sediments such as dunes and mega-ripples. Tectonic activity has also significantly affected Pickering Crater, as indicated by the presence of three 20 to 30 km long en-echelon grabens, partially infilled by lava, on the present-day floor of the crater, and by fault surfaces in the rim. Lava flow fronts are clearly identifiable in MOLA altimetry, MOC-WA and THEMIS images. The surface features of the youngest lava flows are identifiable by MOC-NA images, and are useful to correlate the flows. Lava flow directions are deduced from THEMIS and MOC-NA images. The presence of dikes is inferred. The combined evidence provided by these data allows to construct a preliminary geological map of Pickering Crater. The evidence indicates that lava flows have repeatedly flooded the crater. The youngest lava flows have entered the crater via its NW rim breach. Older lavas appear to record a NNE to SSW flow direction. The relationship between volcanism, grabens and dikes in the Pickering Crater region is complex, and further studies are being conducted to unravel the sequence of volcano-tectonic events in the area.
DE: 5480 Volcanism (6063, 8148, 8450)
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting