The Thermal Evolution of Venus as Recorded by Surface Tectonics
Abstract
The Venus impact crater record suggests that the planet experienced a resurfacing event of virtually global proportions roughly 400 million years ago. The catastrophic resurfacing hypothesis holds that minimal volcanic and tectonic activity has occurred in the interim; a parallel argument is that the lithosphere has cooled and thickened in the post-catastrophic period. We evaluate this postulate by examining correlations between the relative ages of tectonic features and their inferred thermal gradients. Using an instability growth model, we find a high geotherm is necessary to explain the deformation wavelengths of tessera, among the oldest terrains on Venus. Flexure and gravity modeling of coronae and large volcanoes, structures of intermediate age, indicate lower geotherms at the time of formation. Artemis Chasma--a zone of lithospheric underthrusting--is believed to be relatively young; it displays coherent, plate-like tectonics and an extraordinarily low temperature gradient. Together these observations favor the monotonic cooling and thickening of the venusian lithosphere in the past few hundred million years.
- Publication:
-
Lunar and Planetary Science Conference
- Pub Date:
- March 1996
- Bibcode:
- 1996LPI....27..169B
- Keywords:
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- HEAT FLOW;
- LITHOSPHERE;
- TECTONICS;
- TESSERAE;
- VENUS