The Martian olivine-phyric basalt Northwest Africa (NWA) 10416 contains large olivine xenocrysts whose cores have been stained brown by hydrothermal alteration and whose rims are composed of pristine olivine overgrowths. Microanalysis of these olivine cores reveals various degrees of amorphization, some of which have been overprinted by terrestrial weathering, evident as part of a weathering rind along the exposed surface of the meteorite. Studies of a completely unweathered terrestrial analogue basalt from southern Colorado reveal similar features and indicate that both basalts were altered in a supersolidus magma chamber setting. The alteration features in NWA 10416 thus imply the presence of significant quantities of magmatic water on Mars and a potentially unique igneous reservoir.
Northwest Africa (NWA) 11042 is a primitive achondrite whose O isotopes plot with the L chondrites, but whose petrology resembles that of a cumulate igneous rock. It is heavily shocked and contains high-pressure phases, indicating an origin on a large parent body that underwent sufficient heating to completely melt it, and experienced an impact large enough to create extensive shock-melt pockets. Microanalysis of these melt pockets, trace element geochemistry, and isochron radiometric dating reveal a possible origin deep within the L chondrite parent body where temperatures were sufficient to produce an igneous rock.
Earth and Planetary Sciences
Level of Degree
Department of Earth and Planetary Sciences
First Committee Member (Chair)
Second Committee Member
Third Committee Member
Mars, Achondrite, Petrology, Geochemistry, Meteorites, Electron Microscopy
Vaci, Zoltan. "Magmatic Hydrothermal Alteration and Secondary Post-Shock Features in Martian Olivine-Phyric Basalt Northwest Africa 10416; Petrology and Geochemistry of Primitive Achondrite Northwest Africa 11042." (2017). http://digitalrepository.unm.edu/eps_etds/196