Comparative isotope study of two short sediment cores from the Dead Sea

Two short sediment cores from the Dead Sea have been analyzed for the following isotopes: ¹⁸O, ¹³C, ¹³⁷Cs, ²¹⁰Pb, U, Th and ⁴⁰K. In the northerly core, taken from the Jordan River discharge area, the δ¹³C and δ¹⁸O of the carbonates is quite homogeneous and very similar to that found in the suspended material of the inflow. In the southerly core, taken nearshore in the central part of the lake, the stable-isotope composition of the carbonates is depth-variable and generally more enriched in both isotopes. The carbonates of this core are derived from two main sources: allogenic carbonates with an isotopic composition similar to that of the northerly core and endogenic aragonite from the Dead Sea, which is relatively more enriched in both isotopes. ¹³⁷Cs and ²¹⁰Pb are used to show that near the Jordan River inflow sedimentation rates are higher by an order of magnitude over the nearshore central region. The first systematic measurements of U and Th in Dead Sea sediments are presented; the values are found to be within the range encountered in sedimentary environments.