Strontium isotopic, Ostracod fauna, and paleoenvironmental features of the Late Miocene sequence in Mut/Dağpazarı region (Southern Turkey)

Abstract

The Dağpazarı village in the Mut (Mersin-S Turkey) region served as the main subject of the study and from the research area, 2 measured stratigraphic sections have been obtained. By analyzing the ostracod fauna of the Dağpazarı, Ballı and Mut Formations in these portions and using strontium isotope chemostratgraphic dating, the Middle-Late Miocene period in the area was thoroughly examined. The upper levels of the Mut/Köselerli formations, which are Burdigalian and Serravallian, mark the beginning of the Miocene succession in the research region. The Dağpazarı formation, which includes plentiful silty-clay, Ostrea fossiliferous, and lignite layers, is unconformably deposited just above these levels. This formation contains the following ostacode types; Bairdia subdeltoidea, C. glypta, Cytheridea acuminata acuminata, Acanthocythereis hystrix, Krithe monosteracensis, Neomonoceratina mouliana, Hemicyprideis sp., Cistacythereis caelatura, Cyherella terguemi, T. prava, K. langhiana, A. ulicznyi, Pokornyella deformis minor, Loxoconcha alata, Tenedocythere salebrosa. Furthermore, the planktonic foraminifera species are; O. universa, Globigerinoides trilobus, Glb. ruber, Orbulina bilobata, Glb. sacculifer, O. suturalis, and the formation includes abundant bryozoa, echinoid spines, gastropods such as Terebralia at distinct levels and fish otolith. The formation, which dates from the late Serravallian to the early Tortonian, exhibits the shallow reef character that continued to develop in the late Miocene. The formation consists of dark green, bulbous weathered claystone, Bairdia subdeltoidea and Ostrea which are reduced in size at the levels that pass into hard clayey sandstone, abundant benthic foraminifera with abundant echinide spines. The formation is made up of benthic foraminifera, hard clayey sandstone, and weathered dark green claystone with a lot of echinide spines. Ostrea and Bairdia subdeltoidea are also present. The superior section of the examined succession finishes with silty, hard, clayey limestone and light-colored limestone bands. The level, the Tırtar7Ballı formation, which is compatible with the Dağpazarı formation, indicates the top of a recent reef formation in the Tortonian. Ostracod species such as Aurila pigadiana, Thalmannia hodgii, Buntonia sublatissima dertonensis, Bairdia subdeltoidea, Aurila sp. B Bassiouni have been defined. The limestones furthermore include abundant benthic foraminifera and echinoid spines. The ratio of 87Sr/86Sr analyzed from the carbonate sample obtained from the Dağpazarı formation is 0.708920. The age of the Dağpazarı formation was calculated as 8.7 Ma based on these isotope data.