Mathematics – Logic
Scientific paper
Dec 2002
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002agufm.p11b..09m&link_type=abstract
American Geophysical Union, Fall Meeting 2002, abstract #P11B-09
Mathematics
Logic
5415 Erosion And Weathering, 5460 Physical Properties Of Materials, 5464 Remote Sensing, 5470 Surface Materials And Properties, 5480 Volcanism (8450)
Scientific paper
Remarkably well-preserved lava flows and flood channels emanate from the Cerberus Fossae, a set of en echelon fissures trending E-SE from Elysium Mons. Crater counts and models suggest that the most recent volcanic activity (over a broad region) and fluvial activity at Athabasca Valles occurred within 10Ma. However, controversy persists over whether or not this region was recently exhumed from beneath a cover of low-density sediments, and could be older than it appears. We hope to better understand relations between the volcanic and fluvial activity, with implications for the source of water and potential geothermal activity. Was the volcanism and water release driven by the same basic magmatic/tectonic event, or were they separate events that exploited the same fissure system? High-resolution MOC images have been crucial to initial interpretations, but they are widely spaced and cover only a small percentage of the region, except over an area that was under consideration as a landing site for MER. THEMIS provides the missing links: regional morphologic coverage and thermophysical mapping at intermediate resolutions (18 m/pixel visible and 100 m/pixel IR). Temperature variations may directly map bedrock units in this region, which has a thin dust cover that is penetrated by the diurnal thermal cycle. Most of the temperature units closely correspond to morphologic units seen in MOC images, enabling extrapolation of unit maps over the entire region. Ratios of band 4 to band 9 (8.56/12.57 microns) nighttime images have not revealed anomalies suggestive of current geothermal anomalies. Except for dark steep slopes the albedos do not vary strongly, so the nighttime temperature differences must be controlled primarily by variations in thermal inertia; this is consistent with TES results. Relatively high nighttime temperatures correspond to dark rock outcrops in the steep slopes of fossae and craters and to very flat plains with well-expressed patterned ground. Relatively low temperatures correspond to bright dunes and bright-rayed craters; although not resolved by TES they are only slightly brighter than the surroundings so they probably have low thermal inertias. Clusters of bright-rayed craters have a peculiar distribution, concentrated in an E-SE trend parallel to but S of Cerberus Fossae. Recent lava flows have high temperature contrasts due to a low-inertia cover over relatively high-standing plates separated by high-inertia patterned ground, and the trapping of low-inertia eolian materials along flow margins. Channel floors have intermediate thermal inertias, but with streamlined patterns. A morphologic/thermophysical unit map and geologic interpretations will be presented; preliminary results show close spatial relations between source regions and extents of lava flows and flood channels.
Burr Devon
Christensen Paul
Keszthelyi Laszlo
Malin Mike
McEwen Alfred
No associations
LandOfFree
Athabasca Valles Region: New Insights From THEMIS does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Athabasca Valles Region: New Insights From THEMIS, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Athabasca Valles Region: New Insights From THEMIS will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1891788