Stable isotopes of a subfossilTamarixtree from the Dead Sea region, Israel, and their implications for the Intermediate Bronze Age environmental crisis

Abstract

AbstractTrees growing on the Mt. Sedom salt diapir, at the southern Dead Sea shore, were swept by runoff into salt caves and subsequently deposited therein, sheltered from surface weathering. A subfossilTamarixtree trunk, found in a remote section of Sedom Cave is radiocarbon dated to between ∼ 2265 and 1930 BCE. It was sampled in 109 points across the tree rings for carbon and nitrogen isotopes. The SedomTamarixdemonstrates a few hundred years of13C and15N isotopic enrichment, culminating in extremely high δ13C and δ15N values. Calibration using modernTamarixstable isotopes in various climatic settings in Israel shows direct relationship between isotopic enrichment and climate deterioration, particularly rainfall decrease. The subfossilTamarixprobably reflects an environmental crisis during the Intermediate Bronze Age, which subsequently killed the tree ∼ 1930 BCE. This period coincides with the largest historic fall of the Dead Sea level, as well as the demise of the large regional urban center of the 3rd millennium BCE. The environmental crisis may thus explain the archaeological evidence of a shift from urban to pastoral culture during the Intermediate Bronze Age. This was apparently the most severe long-term historical drought that affected the region in the mid-late Holocene.