Reconstructing Mid-Pleistocene paleovegetation and paleoclimate in the Golan Heights using the δ13C values of modern vegetation and soil organic carbon of paleosols

摘要

The Golan Heights borders the Upper Jordan Valley on its eastern side and likely served as a prime foraging area for hominin groups that inhabited the Upper Jordan Valley during the Mid-Pleistocene. This study tests the hypothesis that Mid-Pleistocene climate in the Golan region was similar to that of the present day. Carbon isotope composition of present day plant communities and soil organic carbon from the Golan were compared to those of paleosols from Nahal Orvim to reconstruct Mid-Pleistocene paleoclimatic conditions. After correcting the paleosol values for recent changes in atmospheric carbon isotope values and potential biodegradation, the isotopic results show a strong similarity to those of present day local plants and soils. These results indicate that during the Mid-Pleistocene, the Golan was dominated by C_3 vegetation, shared similar climatic conditions with the present day, and displayed long-term environmental stability. The span of time of paleosol formation is unknown and might cover multiple climatic episodes; thus, although short climatic fluctuations may have occurred, their impact was not substantial enough to be detected in the Nahal Orvim paleosols. This study concludes that the Golan slopes provided hominins and large grazers with a reliable and highly nutritious foraging area that complemented the Jordan Valley riparian ecosystem.