Early Holocene paleosols at the southwestern Ramlat As-Sabʹatayn desert margin: New climate proxies for southern Arabia

The Ramlat As-Sabʹatayn desert margin near Maʹrib, Yemen, displays well preserved Early Holocene paleosols which are documented by AMS 14C and soil data. Mollusc shells in Bwk and Bwkb horizons are dated to the period between 12.5 and 9.5 ka cal BP. The buried soils above (Ahb and ABwkb horizons), indicate a period of soil formation mainly between 8.8 and 8.3 ka cal BP. Between 8.3 and 6.7 ka cal BP more weakly developed soils occur, and those only locally. In contrast to the paleosols, sandy cover sediments (C horizons) without considerable signs of pedogenesis appear due to increasing aridity, wind activity, and sheet wash after 8.3 ka cal BP. These results indicate an arid climate and the formation of cover sediments at the desert margin of Yemen, in the rain shadow of the Yemen Highlands, after the main period of soil formation which ended around 8.3 ka cal BP, at the latest at 6.7 ka cal BP. Calculating from geochemical data a palaeoprecipitation of about 400 to 600 mm a− 1 (± 235 mm a− 1) from 12.5 to 8.3 ka BP is proposed. Accordingly after 8.3 ka cal BP the summer position of the ITCZ and the associated monsoon rain belt carrying rain to northeastern Yemen is assumed not to go beyond 15°N in its whole amplitude.