Felsic highland crust on Venus suggested by Galileo Near-Infrared Mapping Spectrometer data
Article first published online: 31 DEC 2008
Copyright 2008 by the American Geophysical Union.
Journal of Geophysical Research: Planets (1991–2012)
Volume 113, Issue E5, May 2008
How to Cite
2008), Felsic highland crust on Venus suggested by Galileo Near-Infrared Mapping Spectrometer data, J. Geophys. Res., 113, E00B24, doi:10.1029/2008JE003134., , , , , , and (
- Issue published online: 31 DEC 2008
- Article first published online: 31 DEC 2008
- Manuscript Accepted: 18 SEP 2008
- Manuscript Revised: 29 JUL 2008
- Manuscript Received: 2 MAR 2008
- crust composition;
 We evaluated the spatial variation of Venusian surface emissivity at 1.18 μm wavelength and that of near-surface atmospheric temperature using multispectral images obtained by the Near-Infrared Mapping Spectrometer (NIMS) on board the Galileo spacecraft. The Galileo NIMS observed the nightside thermal emission from the surface and the deep atmosphere of Venus, which is attenuated by scattering from the overlying clouds. To analyze the NIMS data, we used a radiative transfer model based on the adding method. Although there is still an uncertainty in the results owing to the not well known parameters of the atmosphere, our analysis revealed that the horizontal temperature variation in the near-surface atmosphere is no more than ±2 K on the Venusian nightside and also suggests that the majority of lowlands likely has higher emissivity compared to the majority of highlands. One interpretation for the latter result is that highland materials are generally composed of felsic rocks. Since formation of a large body of granitic magmas requires water, the presence of granitic terrains would imply that Venus may have had an ocean and a mechanism to recycle water into the mantle in the past.