Late Holocene Neoglacial conditions from the Lesotho highlands, southern Africa: phytolith and stable carbon isotope evidence from the archaeological site of Likoaeng.

The late Holocene environmental history of the Lesotho highlands, southern Africa, is poorly understood with few detailed studies to date. At Likoaeng, Senqu Valley, Lesotho, a 3m stratified sedimentary sequence from an open-air archaeological site records vegetation development for the period 3400–1070cal.BP. Phytolith analyses and bulk sediment organic matter δ13C indicate that C4grassland dominated the lower part of the sequence until approximately 2960cal.BP when there was a switch to C3Pooid grassland (2960–2160cal.BP). Also noted was a change from hunting mainly bovids to a dominance of fishing at the site. The change in grassland type and archaeological subsistence strategies corresponds with an episode of neoglacial cooling and the expansion of Alpine sourgrasses into lower altitudes. From 2160 to 1600cal.BP grassland became a mix of C3and C4types and by 1600–1070cal.BP there was a return to C4dominated grassland. During this latter phase there was a reversal from fishing to hunting again (and eventually some keeping of domestic livestock) at the site. These data outline the vegetation response to latitudinal shifts of frontal systems, and relatively strong atmospheric circulation variability, perhaps underpinned by variations of polar water into the Benguela Current during the late Holocene. [ABSTRACT FROM AUTHOR]