Mark B. Allen1,
(1) CASP, University of Cambridge, Cambridge, United Kingdom
(2) Azerbaijan Academy of Sciences
(3) University of Aberdeen, Aberdeen, Scotland
Abstract: Tectonostratigraphic evolution of the South Caspian Basin
The propagation characteristics of seismic waves across the South Caspian Basin confirm the oceanic character of its basement. There is no consensus as to its age and tectonic setting. Published suggestions for the age range from Paleozoic to Paleogene. Sedimentological and magmatic data indicate major Paleocene-Eocene rifting in adjacent areas, which could be related to the oceanic spreading event.
Oligo-Miocene turbiditic shales of the Maikop Series form the principal source rock. These were deposited in the Paratethyan Ocean. There was syn-depositional deformation of the Maikop in regions adjacent to the Caucasus, interpreted as an early effect of the Arabian-Eurasian collision.
Compressional deformation intensified in the late Miocene, and, together with isolation and base-level fall in the South Caspian Basin, initiated deposition of the fluvial-deltaic Productive Series. This forms the main reservoir interval in the basin. New outcrop data on the Productive Series refine existing depositional models. For example, there is evidence for more lateral variation and incision than was previously recognised.
In the northwest of the South Caspian Basin, Productive Series strata are folded: these are the main trap structures. Deformation began between the late Miocene and late Pliocene. The folds are internally deformed by a hierarchy of smaller scale structures, from thrusts and strike-slip faults with displacements in the order of hundreds of metres, to joints and granulation seams. Exposed faults controlled hydrocarbon migration through sandstones, and are excellent analogues for sub-surface reservoir structures.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana