Terrestrial environmental changes around the Gulf of Aden over the last 210 kyr deduced from the sediment n‐alkane record: Implications for the dispersal of Homo sapiens

Abstract

AbstractWe analyzed long‐chain (C25–C36) n‐alkanes and pollen grains in sediments from the Gulf of Aden covering the last 212 kyr to reconstruct the surrounding terrestrial environment, a critical region for the dispersal of Homo sapiens. Substantial increases in the flux of n‐alkanes during 200–185, 120–95, and 70–50 ka were interpreted to indicate enhanced vegetation biomass in the Arabian Peninsula and the northern part of the Horn of Africa or increase in lithogenic material inputs. Periods of enhanced n‐alkane flux occurred during or immediately after pluvial episodes, indicating that the increased precipitation may have induced substantially enhanced vegetation biomass, creating favorable conditions for Homo sapiens. Additionally, vegetation may have increased due to moderate precipitation unrecorded by speleothems or in accordance with the lowering of sea level, indicating that the dispersal might have been possible even after the shift to an arid environment indicated by the speleothems.