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Crustal development in the terrestrial planetsThe development of planetary crusts may be divided into primary, resulting from melting during accretion, and secondary crusts developed by partial melting from planetary mantles. The Mercurian crust is probably primary with no compelling evidence of later basaltic extrusions. Reflectance spectral evidence for the existence Fe2(+) is equivocal. The Viking Lander XRF data on Mars indicate basaltic material at both sites 4,000 km apart. Surface aeolian processes would be expected to provide a homogeneous average of the crust, but no evidence of more siliceous material is present. This conclusion is weakly supported by the Russian gamma ray data. No evidence for granite appears from the Russian Venera XRF data which indicates MORB-type and alkali basalt (4% K2O) surface compositions. The highlands of Ishtar Terra and Aphrodite probably owe their elevation to tectonic processes rather than compositional effects. Venus may thus resemble the early Archean Earth. The terrestrial granitic continental crust is a product of episodic multiple partial melting events, probably a consequence of the presence of surface water.
Document ID
19850025566
Document Type
Conference Paper
Authors
Taylor, S. R. (Australian National Univ. Canberra, Australia)
Date Acquired
August 12, 2013
Publication Date
January 1, 1985
Publication Information
Publication: Lunar and Planetary Inst. Terrest. Planets: Comp. Planetology
Subject Category
LUNAR AND PLANETARY EXPLORATION
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19850025536Analytic PrimaryTerrestrial Planets: Comparative Planetology