Other
Scientific paper
Dec 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008agufm.p43c1412l&link_type=abstract
American Geophysical Union, Fall Meeting 2008, abstract #P43C-1412
Other
6008 Composition (1060), 6017 Erosion And Weathering, 6055 Surfaces, 6207 Comparative Planetology, 6225 Mars
Scientific paper
We present the first detailed analysis of the composition of some of the Tharsis lava flows. This vast volcanic region displays locally young lava flows which demonstrate the presence of a recent internal activity. These lava flows are among those involved for SNC meteorites such as the shergottites. However, the broad dust cover distributed over the Tharsis region limits any spectral study to the aeolian mantling. We have found within the Tharsis region several areas of interest using OMEGA spectrometer as pyroxene rich. These areas are small outcrops of few km large. They display a high thermal inertia and a low albedo as expected for lava flows devoid of dust. The first region is located on the Echus Chasma floor. This location presents platy textures as seen in several locations on Mars. This texture which is composed by pieces of km sized shallow plateaus separated by smooth interplates. This texture resembles that of rafts of solid material moving over fluids. For this reason, the platy texture is currently under debate between two hypotheses: (1) lava flows with solidified lava rafts over fluid lavas (2) ice raft with icy blocks over liquid water. Here, the spectral data display a strong enrichment in pyroxenes, especially in areas of high thermal inertia that can not correspond to eolian material. Close-ups on MOC show no sandy material that could hide the surface. Therefore, this region is likely a solidified lava flow with a recent age (Late Amazonian). Pyroxenes were also identified in four canyon floors of Noctis Labyrinthus in locations out of apparent sand mantling. These outcrops are rocky with a high thermal inertia, they display flow patterns, and a relative flat topography that embay residual hills. These outcrops therefore likely correspond to lava flows. These textures is unique in Valles Marineris canyons. Crater counts give ages in the Late Amazonian as in Echus Chasma floor. Both regions were studied using models developed to calculate the modal composition of the rock (Poulet et al., LPSC, 2008). These models show a composition dominated by pyroxenes and plagioclases, with a lack of olivine in spectra. Compositions of both areas mainly fit that of classical tholeiitic basalts. Platy textures are very flat and suggest a low viscosity of the lava flows. These lavas with platy textures on Mars can be compared to those observed locally on Earth, as in Iceland. Nevertheless, from the composition found, they do not seem to require a specific olivine-rich composition to explain the low viscosity. Strong lava flux, high temperatures, or other chemical factors might be involved to explain the low viscosity. Of interest is also the HCP/LCP ratio which is of about 4:1 for both regions which is part of the highest on Mars. This ratio is much higher than those of old regions, or that of SNC meteorites. These meteorites are therefore unlikely to come from such magmatic areas. Details on the composition and their analogy to terrestrial lava flows will be given at the conference.
Ansan Véronique
Baratoux David
Bibring J.
Gondet Brigitte
Langevin Yves
No associations
LandOfFree
Composition of recent lava flows in the Tharsis region of Mars and comparison to terrestrial flows 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 Composition of recent lava flows in the Tharsis region of Mars and comparison to terrestrial flows, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composition of recent lava flows in the Tharsis region of Mars and comparison to terrestrial flows will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1238650