The Importance of Mars Samples in Constraining the Geological and Geophysical Processes on Mars and the Nature of Its Crust, Mantle, and Core

关键词: IGNEOUS ROCKS;    MARS SURFACE SAMPLES;    PLANETARY GEOLOGY;   

RP-ID  :  JSC-E-DAA-TN52597

学科分类：空间科学

美国|英语

来源: NASA Technical Reports Server

【 摘 要 】

In situ compositional and mineralogical measurements on the Martian surface, combined with analyses of Martian meteorites, indicate that most igneous rocks are lavas and volcaniclastic rocks of basaltic composition and cumulates of ultramafic composition. Alkaline rocks are common in Early Hesperian terranes and tholeiitic rocks dominate younger Amazonian martian meteorites. Very uncommon feldspathic rocks represent the ultimate fractionation products, while granitoid rocks have not been identified. The impact-driven delivery mechanism for the Martian meteorites biases in favor of more competent samples - young, igneous rocks - and against rocks that are more representative of the Martian crust. Comparisons of rock types found among the meteorites to those documented by landed missions demonstrates this bias unequivocally; furthermore, of the over 100 martian lithologies represented by the martian meteorites, only one (NWA 7034 and pairs) is a regolith breccia.