QUOTE (nprev @ Jul 14 2009, 05:32 PM)
Exciting & interesting, but gotta play skeptic...
Me too, but for additional reasons. Large bodies of granitic rocks on Earth commonly are believed to have used subducted water as a flux (dissolved substance that lowers the melting point), but such a process cannot yet be demonstrated for Venus, which may have lacked both a granitic continental crust and liquid water. In addition, many other dissolved substances besides H2O, including sulfates and carbonates, can act as fluxes in magma (molten rock). Furthermore, if higher elevations on Venus have a different spectral response, this presumably could be caused by temperature effects (including coatings of frost-like mineral condensates) alone.
Even in the absence of fluxes, granitic and intermediate rocks, generally in small amounts, can be formed by the classical, experimentally proven "Bowen mechanism" - extreme fractional crystallization of basaltic magma. This mechanism is how small bodies of granite are believed to have formed on Earth's Moon, for example, in the virtual absence of water. It was once believed to be how all granites formed.
Agree - granite problem probably needs a lander or two.
-- HDP Don (edited after reading original article)