Elemental Composition of the Martian Crust
Harry Y. McSween, Jr.,1,*
G. Jeffrey Taylor,2
Michael B. Wyatt3
The composition of Mars’ crust records the planet’s
integrated geologic history and provides clues to its differentiation.
Spacecraft and meteorite data now provide a global view of the
chemistry of the igneous crust that can be used to assess this
history. Surface rocks on Mars are dominantly tholeiitic basalts
formed by extensive partial melting and are not highly weathered.
Siliceous or calc-alkaline rocks produced by melting and/or
fractional crystallization of hydrated, recycled mantle sources,
and silica-poor rocks produced by limited melting of alkali-rich
mantle sources, are uncommon or absent. Spacecraft data suggest
that martian meteorites are not representative of older, more
voluminous crust and prompt questions about their use in defining
diagnostic geochemical characteristics and in constraining mantle
compositional models for Mars.
2 Hawai’i Institute for Geophysics and Planetology, University of Hawai’i at Manoa, Honolulu, HI, 96822, USA.
3 Department of Geological Sciences, Brown University, Providence, RI 02912–1846, USA.
* To whom correspondence should be addressed. E-mail: mcsween{at}utk.edu
