Age-depth model with δ13Cca and δ18Oca isotope profiles for stalagmite Y99 growth interval-I

The Arabian Peninsula was one key area for H. sapiens dispersals out of Africa. Current dispersal models advocate that dispersals via the "southern route" into Arabia occurred during Glacial Termination-II (T-II), when increased monsoon precipitation and reduced sea-level and Bab-al-Mandab width increased the likelihood of crossing. The precise phasing between sea-level and monsoon precipitation is thus key to assess the likelihood of a successful crossing or the behavioural and technological capacities that facilitated crossing. Based on a precisely-dated stalagmite record from Yemen we reveal a distinct phase-lag of several thousand years between sea-level rise and monsoon intensification. Pluvial conditions in southern Arabia during MIS 5e lasted from ~127.7 to ~121.1 ka BP and occurred when sea-levels were already higher than at present. We propose three models for the dispersal of H. sapiens; all have pertinent implications for our understanding of human technological and behavioural capacities during MIS 5e.