The impact of Indian Ocean - Mediterranean gateway closure on the current and nutrient regime in the Eastern Mediterranean during the early to middle Miocene

Abstract

During the early and middle Miocene, the Mediterranean became a restricted marginal sea with the contraction of the Mesopotamian Gateway and ultimate loss of connectivity to the Indian Ocean. Leading to the transformation of the Mediterranean into a restricted marginal marine sea . Low latitude circumglobal circulation through the basin characterized the basin for most of the Cretaceous and Paleogene. With the loss of this supply of surface and subsurface waters, dramatic changes occurred to the heat, energy, and nutrient budgets across the Mediterranean. The most affected area was the eastern basin. , As is well evidenced by the onset of sapropel formation, many other aspects of the sedimentary system changed in response to this ocean circulation rearrangement. Hemipelagic successions in southwestern Cyprus offer a window into the changes in the subsurface waters occurring in the Eastern Mediterranean through the closure of the gateway to the Indian Ocean. Dated to the late Aquitanian to the early Serravallian (22.5–14.5 Ma), this sequence is carbonate-dominated and overall continues. It exhibits sedimentation with mass transport contribution from shallow water carbonates to deeper facies. The succession exhibits fluctuation of bottom current activity, which was disrupted in the early Burdigalian by mass transports and temporarily halted during the Langhian. Phosphates are present through the entire succession, but most notably in the Langhian. Combined, these lithological characteristics indicate changes in bottom current energy and seafloor ventilation that point to two key intervals of connectivity restriction through the Mesopotamian gateway.