This synthesis draws on the postcruise work of many Leg 180 scientists and their colleagues. Thanks to Alastair Robertson for leading the insightful postcruise field trip to the analogous extensional provinces of the Menderes and Alasehir graben in western Turkey. Andrew Goodliffe helped produce the figures in this paper. Careful reviews by Hugh Davies and Tim Reston helped to improve the manuscript. The publications staff at ODP-TAMU, especially Gigi Delgado, the coordinator for this volume, are gratefully acknowledged. So, too, is Adam Klaus, our ever-helpful staff scientist. This research used data provided by the Ocean Drilling Program (ODP). ODP is sponsored by the U.S. National Science Foundation (NSF) and participating countries under management of Joint Oceanographic Institutions (JOI), Inc. Funding for this research was provided by the NSF (in the USA) and CNRS-INSU (in France). This is SOEST contribution No. 5873 and Géosciences azur contribution No. 395.