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Variations in effective compensation depth across Aphrodite Terra, Venus
Author(s) -
Herrick Robert R.,
Bills Bruce G.,
Hall Stuart A.
Publication year - 1989
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl016i006p00543
Subject(s) - venus , geology , upwelling , mantle (geology) , terrain , tectonics , latitude , geodesy , paleontology , geography , oceanography , cartography , astrobiology , physics
Aphrodite Terra is the largest elevated terrain on Venus and it serves as a focal point in current discussions of global tectonic style. Using the topography and gravity data acquired by the Pioneer Venus Orbiter (PVO) we have estimated an effective depth of Airy compensation for each of 75 orbital arcs that provide fairly uniform areal coverage of the entire province. The most pronounced pattern that emerges is a general increase in compensation depth to the east. The most rapid change occurs near 135°; the average west of there is 70 km, while the average to the east is 230 km. Superimposed on this larger trend are five distinctive regional patterns, four well defined peaks and one interval of widely scattered and poorly constrained depths. The maxima in compensation depth are well correlated with regional topographic highs. While these observations are easily reconciled with the general notion that Aphrodite is a region of crustal divergence, the great depth of compensation is difficult to accord with the more specific suggestion that Aphrodite is a terrestrial type divergent plate margin. The alternative suggestion that Aphrodite, and the other equatorial highlands on Venus, are surface manifestations of hot, upwelling mantle plumes is consistent both with the great depths of compensation and with the pattern of regional peaks and intervening troughs. The broader scale increase in effective depth of compensation from west to east is more enigmatic, but it might reflect an age progression of the plumes.