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Unformatted text preview: eem more primitive? Mars
(continued) Annual Atmospheric Pressure Annual Atmospheric Pressure Variations Dunes Polar Regions Rayed Impact Craters
Rayed Impact Craters
Tornabene, et al.,
Olympus Mons shield volcano
18 km above the surrounding plains (Mauna Loa rises 8.8 km above seafloor)
600 km diameter (Circumscribes 2.65 X area of Ohio)
Basal cliff up to 6 km high (landslides)
Young (perhaps still active) Why is it so big? (plume without plates) Tharsis Martian Meteorites
All are igneous rocks of basaltic or ultramafic composition.
SNC = shergottite (basalt or gabbro), nakhlite (clinopyroxenite),
chassignite (dunite), ALH84001 (orthopyroxenite)
Best evidence for Mars origin
is trapped gases Radiometric ages of SNCs are generally very young, less than
The exception is ALH84001,
which has an age of 4.5 b.y. Spirit rover in Gusev crater Bonus question: who took this photo? Humphrey
Humphrey Normative Mineralogy
Hypersthene 31/26/35% 6/13/0% Magnetite 1.2/1.3/1.7% 4.4/4.3/2.6%
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This note was uploaded on 11/10/2011 for the course GEOL 380 taught by Professor Mcsween during the Spring '11 term at University of Tennessee.
- Spring '11