Other
Scientific paper
Dec 2009
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009agufm.p23a1236m&link_type=abstract
American Geophysical Union, Fall Meeting 2009, abstract #P23A-1236
Other
[5400] Planetary Sciences: Solid Surface Planets, [5470] Planetary Sciences: Solid Surface Planets / Surface Materials And Properties, [5480] Planetary Sciences: Solid Surface Planets / Volcanism
Scientific paper
Evidence of volcano-ground ice interactions on Mars can provide important constraints on the timing and distribution of Martian volcanic processes and climate characteristics. We seek to constrain the presence of volatiles in close association with volcanic activity in the Elysium region of Mars. Northwest of the Elysium Rise is Hrad Vallis, a ~370 m deep, 800 km long sinuous valley that begins in a source region at 34oN, 218 oW. Flanking both sides of the source region is a lobate deposit that extends ~50 km perpendicular from the source and is an average of ~40 m thick. Within the lobate deposit 12 craters have been identified by thermal infrared signatures and morphologies that are distinct from any other craters or depressions in the region. The thermally distinct craters (TDCs) are 1100-1800 m in diameter, 30-40 m deep and are typically circular with central depressions surrounded by ~1 to >6 concentric fracture sets. In order to investigate the origin of the thermal anomalies, as well as scrutinize previous observations made using THEMIS and MOC data, the meter-scale morphology of the TDCs and the surrounding terrain was characterized using images from the CTX (~6 m/pix) and HiRISE (0.25-0.30 m/pix) cameras. Patches of the terrain appear smooth at the meter scale, while fields of cones populate other regions of the surface. The cones are ~30-50 m across at the summit, and ~60-80 m across at the base. Many of the cones have flat summits, while some have a summit crater. The larger cones exhibit channels extending radially away from the summit and decameter-scale pits are observed at the base of many of the cones. The cone morphology suggests they may be the result of the explosive interaction between hot material (lava? mudflow?) and volatiles (either frozen ground or ground ice). Morris and Mouginis-Mark (2006) noted the ejecta surrounding Crater 11 appeared to have a slight “rayed” appearance. HiRISE views of the proposed rays reveal that these are positive-relief features composed of fine-grained material with boulders within the unit, and channel forms appear to extend from some of the rays onto the surrounding terrain. The observed channel forms emanating from the rays are typically <100 m long and ~2 m wide. The source regions for the channel forms appear to be the local topographic highs formed by the rays. A DEM over Crater 11 (created by Harold Garbeil) reveals that the rays are relatively thin, the edges of the crater are not raised, and the sides of the depression, beginning with the outermost fracture, step down gradually along the faults bounding the crater. The HiRISE images reveal that the TDC ejecta contain a large population of ~1-5 m sized blocks, which are absent within the fractures surrounding the central depressions and beyond the crater ejecta halo. This is consistent with their formation from explosive release of material from within the crater. The distribution of the TDCs and their associated large-scale and meter-scale morphologies are consistent with their formation as the result of the explosive interaction between hot, flowing eruptive or shallow intrusive material and frozen ground or ground ice.
No associations
LandOfFree
Volcano/Ice Interaction Origin of Thermally Distinct Craters in Hrad Vallis, Elysium Planitia, Mars 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 Volcano/Ice Interaction Origin of Thermally Distinct Craters in Hrad Vallis, Elysium Planitia, Mars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Volcano/Ice Interaction Origin of Thermally Distinct Craters in Hrad Vallis, Elysium Planitia, Mars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1769007