Palaeoenvironments at Sehonghong, Lesotho

Thesis

This thesis presents palaeoenvironmental analyses of material from Sehonghong rockshelter, a Middle and Later Stone Age site in the highlands of Lesotho. Stable carbon isotope analyses of late Pleistocene and Holocene sediments and faunal enamel allow for an assessment of altitudinal shifts of C3 and C4 grasslands with changing temperature. Oxygen isotope values of faunal enamel reflect regional changes in aridity. Nine new radiocarbon dates from previously undated layers were measured, using the ABOx pretreatment method for charcoal. The dates range from 25 330 ± 130 to 30 710 ± 240 uncalibrated years BP.

The δ13C values of soil organic matter (SOM) in sediments dating from approximately 7 000 BP to 35 000 BP reflect an entirely C3 vegetation community until the end of the Pleistocene. These data confirm a depression of vegetation belts in the region during the last glacial and suggest a temperature difference from today of at least -5 °C. The warming trend during the late Pleistocene was interrupted by a marked increase in the C4 vegetation component at about 14 000 BP. A brief return to a more C3 dominated grassland followed at about 11 000 BP, suggesting a return to cooler, glacial temperatures before the onset of the Holocene. The variable δ13C and δ18O of the faunal enamel samples, all dating to a relatively short period between 33 800 and 35 600 BP, may reflect rapid and frequent climatic changes during MIS 3.

Authors: Loftus, E; Emma Loftus

• Alternative title: Stable isotope analysis of soils and fauna from MIS 3 to the Holocene
• Publication date: 2013
• DOI: 10.5287/ora-j2wd1gzgw
• Type of award: MPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: radiocarbon dates; Lesotho; Middle and Later Stone Age; palaeoenvironments; stable isotopes
• Subjects: Stable isotope geochemistry; Sehonghong; Radiocarbon dating; Archaeology; Palaeoenvironmental change