Reconstruction of pre-rift Pyrenean relief in the Oligo-Quitanian Camargue Basin (Gulf of Lion passive margin, SE France): Implications on thermal history of basins
- Univ. Montpellier II (France); and others
Fault reconstruction techniques commonly assume horizontal pre-rift level datum to calculate fault geometry from hanging-wall geometry or viceversa. Example from Camargue basin shows that neglecting pre-rift relief may lead to important errors in calculating the fault and hanging-wall geometries, and the total extension. These errors have direct implications on reconstruction of the thermal history of basins. The Camargue basin results front NW-SE extension and rifting of the Gulf of Lion passive margin. More than 4000m of Oligo-Aquitanian syn-rift series unconformably overlie a crust previously thickened during Pyrenean orogeny. The half-graben basin is controlled by the SE-dipping listric Nimes basement fault which generated a typical roll-over. As both fault and hanging-wall geometries are constrained, the pre-rift surface topography can be restored, using three reconstruction techniques. Either the constant-bed-length and constant-heave techniques produce a depression in the axis of the basin and a relief (1500m and 12(X)m respectively) atop the roll-over. The simple-shear (a=60{degrees}) technique generates a 1500m topography atop the roll-over, more coherent with regional data. Testing the hypothesis of a pre-rift horizontal datum leads to a roll-over 1400m too deep. Pre-rift surface elevation corresponds to the residual topography herited from the Pyrenean orogeny. Consequently, there has been some 1000m subsidence more than predicted by the syn-rift sedimentary record.
- OSTI ID:
- 127347
- Report Number(s):
- CONF-950995-; ISSN 0149-1423; TRN: 95:005942-0040
- Journal Information:
- AAPG Bulletin, Vol. 79, Issue 8; Conference: International conference and exhibition of the American Association of Petroleum Geologists, Inc.: managing change at the turn of the century, Nice (France), 10-13 Sep 1995; Other Information: PBD: Aug 1995
- Country of Publication:
- United States
- Language:
- English
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