Subsidence and uplift mechanisms within the South Caspian Basin: insights from the onshore and offshore Azerbaijan region

Abstract

A combination of fieldwork, basin analysis and modelling techniques has been used to try and understand the role, as well as the timing, of the subsidence -uplift mechanisms that have affected the Azerbaijan region of the South Caspian Basin (SCB) from Mesozoic to Recent.Key outcrops have been studied in the eastern Greater Caucasus, and the region has been divided into several major tectonic zones that are diagnostic of different former sedimentary realms representing a complete traverse from a passive margin setting to slope and distal basin environments. Subsequent deformation has caused folds and thrusts that generally trend from NW-SE to WNW-ESE.Offshore data has been analysed to provide insights into the regional structural and stratigraphic evolution of the SCB to the east of Azerbaijan. Several structural trends and subsidence patterns have been identified within the study area. In addition, burial history modelling suggests that there are at least three main components of subsidence, including a relatively short-lived basin-wide event at 6 Ma that is characterized by a rapid increase in the rate of subsidence.Numerical modelling that includes structural, thermal, isostatic and surface processes has been applied to the SCB. Models that reconcile the observed amount of fault-controlled deformation with the magnitude of overall thinning of the crust generate a comparable amount of subsidence to that observed in the basin. In addition, model results support the tectonic scenario that SCB crust has a density that is compatible with an oceanic composition and is being under-thrust beneath the central Caspian region.

Lithospheric mantle heterogeneities beneath the Zagros Mountains and the Iranian Plateau: a petrological-geophysical study

“…The South Caspian Basin, at the northern edge of our A-A profile, represents the deepest basin in the world with more than 17-km-thick Oligocene-Recent sedimentary succession, mildly folded and thrusted as a result of the Arabian-Eurasia collision (e.g. Egan et al 2009). …”

Cenozoic-Recent tectonics and uplift in the Greater Caucasus: a perspective from Azerbaijan

“…The period of Late Eocene to present relates to the development of a foreland basin coeval with shortening and uplift in the adjacent Greater Caucasus range. In the Black Sea and South Caspian basins , the much more rapid Pliocene-Quaternary phase of sedimentary infill as well as subduction related subsidence in the north of South Caspian (Egan et al 2009) occurred simultaneously with the asymmetrical subsidence of Caucasus-related molasse basins to the north and south (Ershov et al 1999. A crustal/lithospheric -scale model suggests that crustal thickening and removal of lithospheric roots are responsible for supporting the Caucasus Mountains.…”

“…They correspond to the original palaeogeographic setup and build upon inherited, pre-existing structures (Egan et al 2009). Lateral correlations and differences can be made between the western region in Crimea (Saintot et al 1998;Saintot & Angelier 2000;Saintot et al 2006a), through Georgia (Gamkrelidze & Rubinstein 1974;Gamkrelidze & Gamkrelidze 1977;Banks et al 1997) to the Caspian Sea (Kangarli 1982(Kangarli , 2005Allen et al 2003;Egan et al 2009). The Adjara-Trialet FTB in Georgia located to the south of the southern limit of the Greater Caucasus in Georgia (Banks et al 1997;Gudjabidze 2003) is of particular interest since thrusting is top to the North, opposite the direction in the GC (Gamkrelidze & Kuloshvili 1998).…”

Tectonic Models for the Evolution of Sedimentary Basins

“…indicate its ongoing deformation.6.12.4.2.2.4 The South Caspian BasinThe South Caspian Basin with an estimated sedimentary thickness up to 20 km(Brunet and Cloetingh, 2003;Egan et al, …”