--> ABSTRACT: Crustal Thinning, Extension, Heat Flow, Subsidence Across a Tertiary Passive Margin: The Gulf of Lions Case Study, by M. Auzende, J. L. Burrus, J., A. Galdeanos, P. Labaume, D. Lajat, M. Mauffret, J. L. Olivet, P. Patriat, G. Pascal, B. Pinet, B. De Voogd; #91003 (1990).

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ABSTRACT: Crustal Thinning, Extension, Heat Flow, Subsidence Across a Tertiary Passive Margin: The Gulf of Lions Case Study

M. Auzende, J. L. Burrus, J., A. Galdeanos, P. Labaume, D. Lajat, M. Mauffret, J. L. Olivet, P. Patriat, G. Pascal, B. Pinet, B. De Voogd

The Gull of Lions is a passive margin that borders the small oceanic domain of the Provencal basin, located south of France. The Gulf of Lions is a segment of the western European rift system created during the Oligocene-Miocene. Numerous data (industrial seismic reflection, refraction, and heat-flow measurements) have been used to investigate the geodynamic evolution of the margin. These data showed that this young passive margin presents a conventional structure (important crustal thinning, up to ß = 5, associated with block faulting, sealed by a postrift unconformity) and a rather typical evolution (synrift, postrift, and present heat flow are roughly in agreement with model predictions assuming a uniform extension). According to previous interpretation, it was p oposed that the margin had undergone very small horizontal extension in apparent contradiction with model prediction.

This paradox is investigated in light of a deep seismic profile acquired in 1988-1989 by the ECORS group. This 300-km profile (15 sec two-way travel time) images the structure of the margin down to the Moho. The profile suggests that the paradox of stretching can be explained in part by the role of prerift structural inheritage (Pyrenean structuration clearly visible below the margin), and intense block ,deformation during the extension.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990