A Late Miocene – Early Pliocene Paratethyan Type Ostracod Fauna From the Denizli Basin (Sw Anatolia) and Its Palaeogeographic Implications

Abstract

The upper Miocenelower Pliocene sedimentary succession of the Denizli Basin (SW Anatolia) displays a unique record of undisturbed stratigraphy and provides an excellent opportunity to study long-term palaeoecological changes. This paper documents the ostracod assemblages of two sections of the Neogene Kolankaya Formation, resulting in the following taxonomic, palaeobiogeographic and ecological interpretations. The ostracod assemblages from the two sections consist of a mixture of oligohaline to mesohaline tolerant taxa but expose fundamental differences in their composition. This is reflected by the fact that out of 32 determined species, both sections only have 3 in common. In the stratigraphic older succession, the diverse ostracod fauna resembles taxa known from the Paratethys. Faunal relations to the brackish lake habitats of the Euxinic and Pannonian basins are apparent and the palaeobiogeographic significance of the fauna is discussed. The ostracod association of the younger section indicates a low brackish water habitat with fluctuating salinities, most likely in the oligohaline range. The ostracod assemblage of the Kolankaya Formation only permits a broad age assignment to the late Mioceneearly Pliocene.

The myth of the Messinian Dardanelles: Late Miocene stratigraphy and palaeogeography of the ancient Aegean-Black Sea gateway

“…The existence of such a gateway was previously documented in regional palaeogeographic maps (Fig. 13) and may help to explain the enigmatic presence of late Miocene Paratethyan mollusc and ostracod species in the lacustrine deposits of the Denizli Basin of southwestern Turkey (Lazarev, 2020;Rausch et al, 2020).…”

“…The late Miocene Paratethys Sea, the unified precursor of the Black Sea-Caspian Sea, was also connected to the Mediterranean-Aegean basin through a shallow marine gateway, as evidenced by the presence of late Miocene Paratethyan faunas in sections in northern Greece and western Turkey al., 1989;Rögl et al, 1991;Syrides, 1998;Popov and Nevesskaya, 2000;Popov et al, 2006) and Mediterranean fauna in sections in Romania and Russia (Krijgsman et al, 2010;Radionova et al, 2012;Stoica et al, 2013;Golovina et al, 2019;Lazarev et al, 2020). The exact position of this Miocene gateway is still uncertain (Van Baak et al, 2016b;Karakitsios et al, 2017); one option being a gateway through the Balkans (Stevanovic et al, 1989;Suc et al, 2015), the alternative an ancient Bosphorus/Marmara/Dardanelles connection (Lüttig and Steffens, 1976;Popov et al, 2006).…”

“…The oldest Paratethyan fauna in the Aegean region is attributed to the middle Miocene (Umut et al, 1983). Late Miocene Paratethyan mollusk and ostracod assemblages are more widespread (Gramann and Kockel, 1969;Rögl et al, 1991;Popov and Nevesskaya, 2000) and have been observed as far south as the Denizli Basin in southwestern Turkey (Stevanovic et al, 1989;Wesselingh et al, 2008;Lazarev, 2020;Rausch et al, 2020). The mollusk fauna in Denizli is dominated by endemic species, and several of the mollusk lineages.…”

“…These Pontocaspians nowadays form an isolated brackish (anomalohaline) fauna living in the Caspian Sea, Aral Sea and the estuarine regions of the Black Sea (Alçiçek et al, 2015;Wesselingh et al, 2019). The exact migration time and pathway of these particular species to southwestern Turkey remains a mystery (Lazarev, 2020;Rausch et al, 2020), but their ancestors most likely originated in the Paratethys and passed through the Aegean domain, and potentially via an ancient Dardanelles…”

“…Accurate age correlations within the Paratethys domain have long been hampered by the absence of a reliable geological time scale for the region. In the last two decades, numerous studies focused on the integration of biostratigraphy, magnetostratigraphy and Ar-Ar dating in the Paratethys domain and have provided coherent correlations to the standard GTS, especially dating the late Miocene evolutionary development of mollusks and ostracods (Stoica et al, 2007(Stoica et al, , 2013(Stoica et al, , 2016Krijgsman et al, 2010;Vasiliev et al, 2011;ter Borgh et al, 2013;Van Baak et al, 2015, 2016bLazarev et al, 2020). With this updated chronologic framework for the Paratethys now available, we are confident that we are able to improve the age estimates of faunal elements in the enigmatic Formation of the Dardanelles region through an integrated stratigraphic study.…”