Late Quaternary paleoclimatic and paleoenvironmental changes in the Konya Closed Basin (Konya, Turkey) recorded by geochemical proxies from lacustrine sediments

Abstract

The Konya Closed Basin is an important basin in central Turkey, in terms of its geographic position, Quaternary infills, and well-preserved archeological sites. It comprises Quaternary lake marls and other, mainly fine grained, sediments with locally in excess of 400 m. Geochemical data for samples taken from the 7-m-deep Adakale trench from the late Quaternary lacustrine sediments in the Konya Closed Basin are presented and have been used as proxies to elucidate the past climatic changes, weathering regime, redox conditions, and productivity. Climate changes observed in the studied samples for last 50,000 years were represented by oscillations in weathering processes, detrital input, redox conditions, water levels, and paleoproductivity. Geochemical data show that three periods of high detrital input (high Si+Al+K+Ti+Fe, high Ti/Al, Rb/Sr, low Ca and low Si/Ti), four periods of anoxic conditions (low Mn and Th/U and high Ni/Co, Mo/Al and V/Cr), and four periods of higher productivity (high Cu/Al, Ni/Al, Ca/Al, Ba/Al Si/Ti and Ca/Ti) were effective in the study area. These periods are corresponding to climatic changes during last glacial periods, the warm climate of Dansgaard-Oeschger (D/O) events (D/O 2-12) and the cold climate of Heinrich events (H 2-5).