A paleoenvironmental test of the Messinian Salinity Crisis using Miocene–Pliocene clays in the Adana Basin, Southern Turkey

Abstract

The Messinian Salinity Crisis is an important paleooceanographic event around the Mediterranean area. Due to the collision of the North African Plate with the European Plate the Mediterranean area lost its connection to the Atlantic. The Mediterranean sea became shallower; the biota changed and thick evaporitic beds were formed. Paleoenvironmental characteristics of Upper Miocene–Pliocene units of the Adana Basin have been explained by using clay mineralogy analysis. For this purpose, X-ray diffraction studies were carried out on 85 samples collected. In the Upper Miocene–Pliocene sequence high kaolinite content of siltstone, claystone, sandstone, marl and silty marl of the Tortonian units indicates a humid climate. During the Messinian, the content of kaolinite decreased, indicating that the area was arid. After the Messinian, the kaolinite content increased again, showing that environmental conditions of the area became humid again. Correlations of illite and smectite content indicate humidity and temperature of the paleoenvironment, according to previous studies carried out in sequences related to the Messinian Salinity Crisis. The illite content increased in the Tortonian, diminished during the Messinian and increased again in the Pliocene while the smectite ratio showed the opposite trend. In this study, illite ratio is increased during Tortonian and Messinian and decreased in Pliocene while smectite ratio is increased from Tortonian to Pliocene.