Provenance patterns in a neotectonic basin: Pliocene and Quaternary sediment supply to the South Caspian

Abstract

The South Caspian Basin has accumulated a sedimentary succession ∼20 km thick. Roughly half of this was deposited in the last 5.5 Ma, mainly in the largely lower Pliocene, fluvio‐lacustrine Productive Series, which is also the principal hydrocarbon reservoir succession in the basin. Heavy mineral data identify different sediment sources for both Productive Series sandstones and modern river sands. Lesser Caucasus sediment was supplied by the Palaeo‐Kura into the western part of the South Caspian Basin. Productive Series strata in the north of the basin were supplied by the Palaeo‐Volga, and represent a mixture of sediment from the Greater Caucasus and Russian Platform/Urals. Greater Caucasus sand input to the Palaeo‐Volga increased at the start of deposition of the Pereriva Suite, which is an important reservoir subunit of the Productive Series. We interpret this provenance shift as indicating enhanced uplift and exhumation of the Greater Caucasus within the Pliocene, during regional re‐organization of the Arabia–Eurasia collision, although late Cenozoic climate changes may have played a role.

Late Cenozoic reorganization of the Arabia‐Eurasia collision and the comparison of short‐term and long‐term deformation rates

“…It is not clear whether this change has occurred gradually since the mid-Tertiary, or by abrupt reorganization(s). The Pliocene is a candidate time for a reorganization, given the onset of magmatism within the range [Gazis et al, 1995] and the increased contribution of sand from the Greater Caucasus deposited in the adjacent South Caspian Basin [Morton et al, 2003]. Therefore the Greater Caucasus is similar to the Turkish-Iranian plateau in several ways: seismicity, and presumably shortening, is focused on lower altitude areas at its margins, present convergence rates across the range Figure 7.…”

“…Upper Miocene shallow marine strata in the eastern Greater Caucasus (Azerbaijan) are folded and exposed [Azizbekov, 1972]. Provenance data for the uppermost Miocene-Pliocene succession in the northwest of the South Caspian Basin show an increase in the proportion of sand derived from the Greater Caucasus within this interval [Morton et al, 2003]. Summarizing these data, there is evidence for mid-Tertiary uplift, foreland basin development and presumably deformation of the Greater Caucasus; the area involved has apparently increased over time.…”

Provenance of the Bosnian Flysch

“…Additional garnet populations are also observed: one is derived, according to the classification scheme of Morton et al (2003), from amphibolite to granulite facies metapelites (along the almandine-pyrope join) and another one from amphibolite to eclogite facies metabasic rocks (pyrope-and grossular-rich almandines; Fig. 8).…”

Rapid Pliocene exhumation of the central Greater Caucasus constrained by low‐temperature thermochronometry

“…Whether or not this deformation led to significant crustal thickening and exhumation in the Paleogene, however, remains unclear [e.g., Cloetingh et al, 2007]. Other authors [e.g., Zonenshain and Le Pichon, 1986;Philip et al, 1989;Khain, 1994;Ershov et al, 2003;Morton et al, 2003] have suggested late Miocene onset of deformation and uplift. Their conclusions are supported by the widespread occurrence of late Miocene conglomerates, the influx of Greater Figure 1.…”