Geochemistry of Martian Basalts with Constraints on Magma Genesis
When
Where
Associate Professor
Southern Illinois University
Geochemistry of Martian Basalts with Constraints on Magma Genesis
Basaltic rocks analyzed in situ from MER Spirit and Opportunity and MSL Curiosity are more diverse in composition than the rocks represented by the Martian meteorites suggesting they may have tapped a different source region. Surface rocks have more variable Si contents, and higher total alkalis than shergottites. Surface rocks are also ancient while shergottites are young. Therefore, we can use the difference in chemistry and age to constrain the thermal and chemical evolution of the Martian interior.
Petrologic estimates for genesis of Martian magmas come from two main techniques: geochemical modeling and experimental petrology. High-pressure, high-temperature experiments have been conducted on 2 Martian meteorites and 2 surface basalts to reveal their multiple saturation pressure, which has been equated to average melting conditions. Geochemical Modeling has been conducted for basalts at Gusev Crater, Merdiani Planum, and Gale Crater, average surface volcanic compositions, as well as some Martian meteorites [10-14].
Here, I will compare P-T estimates for basalt formation for rocks from the Noachian (Gale Crater, Gusev Crater, Bounce Rock in Meridiani Planum, and a clast in NWA 7034), Hesperian (surface volcanics), and Amazonian (surface volcanics and shergottites), to calculate an average mantle potential temperature (TP) for different Martian epochs and investigate how the thermal state of the interior of Mars has changed through time.
Host: Dr. Timothy Swindle