Sedimentary response to current and nutrient regime rearrangement in the Eastern Mediterranean Realm during the early to middle Miocene (southwestern Cyprus)

Abstract

During the early and middle Miocene, the Mediterranean had become a restricted marginal marine sea with diminishing and ultimate loss of connectivity to the Indian Ocean. This dramatically changed the heat, energy, freshwater and nutrient budgets across the Mediterranean and most notably in its eastern basin. While one of the most prominent lines of evidence of this change in the Eastern Mediterranean is the onset of sapropel formation, many other aspects of the sedimentary system changed in response to this rearrangement. Here we present a detailed analysis of a hemipelagic succession from southeastern Cyprus dated to the late Aquitanian to the early Serravallian (22.5 – 14.5 Ma). This sequence is carbonate-dominated and formed during the decoupling of the Mediterranean Sea and the Indian Ocean. It exhibits sedimentation with mass transport contribution from shallow water carbonates to deeper facies with phosphatization and bottom current (at intermediate depth) interactions. This succession traces both local subsidence and loss of a local carbonate factory. Additionally, it records a shift in bottom current energy and seafloor ventilation, which are an expected outcome of connectivity loss with the Indian Ocean.

Mixed carbonate-siliciclastic contourite drift deposits associated with the entrance of an Atlantic-Mediterranean corridor (late Miocene, southwest Spain)

“…However, this feature is not observable in muddy or sandy contourites where the homogeneity of the sediment does not allow identifying changes in grain size (Shanmugam, 2017;Stow and Smillie, 2020). A high degree of bioturbation is also characteristic of contourite drift deposits, and contributes to the homogenization of the sediment (Wetzel et al, 2008;Rodríguez-Tovar and Hernández-Molina, 2018;Reolid et al, 2021;Bialik et al, 2022). In fossil examples cropping out onshore, carbonate drifts show traction sedimentary structures from lenticular and flaser bedding to mega cross-bedding, which are considered indicative of deposition under the action of bottom currents (Stow et al, 1998(Stow et al, , 2002Shanmugam, 2000;Martín-Chivelet et al, 2008;Hüneke et al, 2020;Reolid et al, 2021).…”

Paleocene to Miocene southern Tethyan carbonate factories of the Southwestern and Western Central Asia

“…The Oligocene is the coldest period of the Paleogene (Zachos et al, 2001), and it is recognized worldwide as a period of great abundance of CC (Dishon et al, 2020). During the early Miocene CC are still very common, but during the middle Miocene, worldwide, RCA become significantly more abundant in tropical shelf at the expenses of CC (Esteban, 1979Halfar and Mutti, 2005;López-Pérez, 2005;Cornacchia et al, 2021;Bialik et al, 2022). CC abundance increases again in the late Miocene in the Western Tethys (Esteban, 1979Pomar and Hallock, 2007;Pomar et al, 2017;Cornacchia et al, 2021) and in the Plio-Pleistocene in the East Pacific and in the Caribbean (López-Pérez, 2005;Johnson et al, 2008).…”