A thermal test of the post-subduction tectonic evolution along the California transform margin

Abstract

The heat flow pattern along the transform margin of western North America reflects the nature of the tectonic evolution following the cessation of subduction. Whereas the high heat flow in the California Coast Ranges shows post-subduction heating, the low heat flow in the Great Valley and Sierra Nevada still reflects the Cenozoic subduction thermal regime. We analyzed a combined heat flow dataset from these regions and compared the thermal implications of the proposed two end member tectonic models, namely the slab window and the stalled slab models. The results show that persistence of low heat flow in a wide region agrees better with the stalled slab model. The Coast Range thermal anomaly could be due to combined effects of thermal relaxation of the stalled slab; viscous heating in the ductile zone; and/or an apparent high surface heat flow due to rapid erosion. Copyright 2008 by the American Geophysical Union.