The Color of the Surface of Venus

Abstract

Multispectral images of the basaltic surface of Venus obtained by Venera 13 were processed to remove the effects of orange-colored incident radiation resulting from interactions with the thick Venusian atmosphere. At visible wavelengths the surface of Venus appears dark and without significant color. High-temperature laboratory reflectance spectra of basaltic materials indicate that these results are consistent with mineral assemblages bearing either ferric or ferrous iron. A high reflectance in the near-infrared region observed at neighboring Venera 9 and 10 sites, however, suggests that the basaltic surface material contains ferric minerals and thus may be relatively oxidized.

Derivation of primary magmas and melting of crustal materials on Venus: Some preliminary petrogenetic considerations

“…If the Venusian mantle is highly reducing, C-H-O fluids are dominated by methane rather than HZ0 and COz. If the Venus crust is highly oxidized (Pieters et al, 1986), introducing oxygen by subducting oxidized crust into methane-bearing mantle creates Hz0 which allows the mantle wedge to melt and could lead to terrestrial-like talc-alkaline volcanism.…”

Detection of Sub-Micron Radiation from the Surface of Venus by Cassini/VIMS

“…Room temperature spectra are displayed; spectra at venusian surface temperatures near 470 • C would exhibit slightly broader absorptions (cf. Pieters et al 1986). The five spectral windows can be effectively used to distinguish ferric (hematitite) and ferrous minerals (e.g., the pyroxenes augite and hypersthene; olivine).…”

“…In addition, ferric materials such as the ferric oxide hematite should be readily recognizable. Indeed, hematite has previously been suggested as a match for Venera 9 and 10 lander spectral reflectance data (Pieters et al 1986). Moreover, its presence has been predicted theoretically and demonstrated in the laboratory under simulated venusian environmental conditions as the dominant end-product of geochemical weathering of the volcanically-generated iron sulfides pyrite and pyrhotite (Fegley et al 1995(Fegley et al , 1997.…”

Iron Mineralogy of Venus' Surface Investigated by M�ssbauer Spectroscopy

“…Laboratory experiments, Venera lander observations, and theoretical models suggest that hematite is present and presumably forms by atmospheric weathering on Venus' surface (Pieters et al 1986, Fegley et al 1995a,b, 1997b. Transmission MB spectra of terrestrial tholeiitic basalt before and after thermal oxidation show that MB spectroscopy can easily detect percent levels of magnetite and hematite and distinguish between the two oxides (Fegley et al 1995b, 1997a.…”