TORNE, MONTSERRAT, and ENRIC BANDA*, Institute of Earth Sciences (CSIC), Barcelona, Spain

ABSTRACT: Neocene Rifting History of the Valencia Trough, Western Mediterranean

The Valencia trough is a Neogene extensional basin of the western Mediterranean that originated in an overall compressional regime. The basin is northeast-southwest oriented, bounded to the north by the Gulf of Lions (Provencal basin) where oceanic crust is recognized, and to the northwest and southeast by the Catalan Coastal ranges and Balaeric promontory, respectively. A wealth of geophysical data collected over the last decade allows a fairly precise picture of its crustal structure, indicating a fundamental asymmetry in its deep structure. Crustal thinning shows a steeper attitude at the Balaeric margin and maximum thinning occurs in the center of the basin (11 km of crystalline crust). Along the axis of the trough, the Moho deepens southwestward from 13 to 16 km, in contrast to t e regional heat flow that increases from about 65 to 85 mW/sq m.. Thermal modeling of the northeastern part of the basin constrained by tectonic subsidence/uplift obtained by flexural backstripping and observed heat-flow data shows that the best fit corresponds to a finite rifting model with a rifting period of 16 Ma. This model, however, does not apply in the southern end of the trough, where the observed heat-flow values are higher and the tectonic subsidence less than expected. Three-dimensional backstripping studies have also shown that the extended lithosphere has acquired little or no strength following rifting.

AAPG Search and Discovery Article #90990©1993 AAPG International Conference and Exhibition, The Hague, Netherlands, October 17-20, 1993.