Tectonic effects of climate change on Venus

Abstract

Venusian plains regions are commonly crossed by small-strain deformation features such as wrinkle ridges, polygonal terrains, and gridded terrains. Of these, polygonal terrains are observed to have a relatively uniform spacing and are widely distributed on plains that formed during global resurfacing. Models of Venusian climate that assume resurfacing occurred through massive volcanic events suggest that surface temperatures could have dramatically changed over nearly a billion years, propagating thermal stresses into the surface and potentially causing small-strain features. We investigate this hypothesis by approximating the temperatures predicted by climate models as a step function and employ a fixed plate and strength envelope model to predict the resulting depth of failure and amount of strain. Our calculations indicate that strains due to temperature changes of 50-100 K, which are favored for volcanic resurfacing events of 1-10 km thickness, are consistent with the observed spacing of polygonal and gridded terrains as well as some wrinkle ridges. The global nature of the climate change event is consistent with the global distribution and uniformity of such features and implies that such terrains may be a global stratigraphic marker. Copyright 1999 by the American Geophysical Union.