A Multi Sensor Core Logger application on sediment cores BAF35-37-46 (Lake Bafa, Western Anatolia)

A high resolution geophysical study is carried out on sediment piston cores (BAF35: 3.05m, BAF 37:4.17m, BAF 46:3.14m), collected from Lake Bafa, along a north-south profile. Down core analyses of several geophysical... [ view full abstract ]

A high resolution geophysical study is carried out on sediment piston cores (BAF35: 3.05m, BAF 37:4.17m, BAF 46:3.14m), collected from Lake Bafa, along a north-south profile. Down core analyses of several geophysical properties, such as gamma density and magnetic susceptibility (MS) values are determinated by Geotek Multi Sensor Core Logger (MSCL) in 0.5cm resolution. Basically, MS values indicate magnetization degree of the sediments, basically positive values suggest that the analysed sediment might be paramagnetic, ferromagnetic, ferromagnetic or antiferromagnetic. Density values are known as an indicator for porosity and lithology variations. Additional sedimentological approaches are also applied to determine lithological characteristics. Hereby, grain size distributions are evaluated by using laser aided particle size analysis in 5cm resolution.

Lake Bafa is known as one of the most significant lake system located in Western Anatolia. Modern conditions of the lake basin are a water surface of 315km2, volume of 692hm3 and a maximum depth 20m. Sediment record indicate mainly homogenous clayey silt distribution, however several sand, and silty sand layers are also documented. The uppermost homogenous clayey silt unit reflect low MS values (1.5-4u.S.I.) along the BAF37 and BAF46 cores, however relatively higher MS values are observed in the core BAF35 (5-20u.S.I.). Even though sediment units containing sandy layers would reflect moderate MS values in BAF37 (0.5-7u.S.I.) and BAF46 (1-2u.S.I.) cores, an additional characteristic unit, with an intensive MS signal is also observed in the lowermost 0.5m part of the BAF35 core (MS: 30-50u.S.I.). A wide range of fluctuation of gamma density values (1.45-5 g/cm3) are also detected in this characteristic sedimentary unit.

Geological evaluation of the Lake Bafa and its separation from the former Latmian Gulf have been controlled by the progradation of the Great Menderes Graben valley and additional marine influences are also recorded during the Quaternary (Müllenhoff et.al., 2004: Knipping et.al., 2008; Kazancı et.al., 2009). A cross correlation of this high resolution geophysical and sedimentological data allowed us to reconstruct the environmental and geological evaluation of Lake Bafa, extending back to ca. 2500 years.