--> Abstract: Late Neogene Tectonics of the South Caspian Basin, Azerbaijan, by J. W. Granath and O. W. Baganz; #90942 (1997).

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Abstract: Late Neogene Tectonics of the South Caspian Basin, Azerbaijan

GRANATH, JAMES W., and O.W. BAGANZ

The South Caspian Basin is a tectonically active intermontane Paratethyan basin, perhaps unique among petroleum-bearing basins in that it is underlain by anomalous crust whose physical properties are comparable to oceanic material. Its thickness, seismic velocity, fiexurally-defined shape, and regional tectonic history suggest that it is a fragment of Mesozoic marginal sea. For the last 5 Ma, the basin has undergone accelerated subsidence so that up to 10 km of Pliocene and younger sediment has accumulated along the northern edge of the basin, in front of the Apsheron Sill. A triangular shaped isostatic anomaly as large as -145mGal Bouguer centered on Baku and the kinematic implications of two key earthquake trends suggest that the northwestern corner of the South Caspian Basin is beginning to subduct under Eurasian continental crust, with a component of clockwise rotation relative to the Kura Basin and Caucasus Mountains to the west. Subsidence is apparently driven in part by negative buoyancy of the crystalline basement, with the sedimentary prism of the Apsheron trough equating to trench fill. The basement appears to be delaminating from the basin fill and sinking with its lithospheric mantle, while the sedimentary fill of the basin deforms independently as a result of convergence between Eurasia and Tethyan blocks. The style of deformation in the sedimentary prism is that of an unusual fold belt: very high amplitude upright folds associated with mud volcanoes and diapirs, as might be expected in a very weak and thick sedimentary succession with unusually weak detachment horizons.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria