Two million years of environmental change : a case study from Wonderwerk Cave, Northern Cape, South Africa
The arid interior of South Africa lacks long, continuous and well-dated climate and environmental proxy records that can be compared with cultural sequences and with broader global climate records. This thesis develops the first substantial terrestrial environmental sequence for the interior of southern Africa at the site of Wonderwerk Cave, spanning two million years of prehistory. Changes in vegetation and humidity over time were investigated by means of carbon and oxygen stable isotope analysis on fossil herbivore enamel and ostrich eggshell, creating two independent proxy datasets. The Holocene record was used as a baseline for comparing the Pleistocene sequence, but required chronological tightening. Therefore, nine new radiocarbon dates were obtained, and calibrated and modelled with existing dates to provide a firmer chronology. The ostrich eggshell isotope record suggests arid but variable conditions, with distinct phases of increased humidity in the Early Pleistocene and mid-Holocene. Enamel stable isotope results show clear differences in local resource availability between the Early and Mid-Pleistocene, and then between the Pleistocene and Holocene, with an overall trend of increasing aridity. In
Ecker, Michaela Sarah
Human evolution ; Environmental archaeology ; Oxygen--Isotopes--Analysis ; Carbon--Isotopes--Analysis ; Cave ecology--South Africa ; South Africa--Antiquities ; South Africa--Environmental conditions
Two million years of environmental change : a case study from Wonderwerk Cave, Northern Cape, South Africa. The arid interior of South Africa lacks long, continuous and well-dated climate and environmental proxy records that can be compared with cultural sequences and with broader global climate records. This thesis develops the first substantial terrestrial environmental sequence for the interior of southern Africa at the site of Wonderwerk Cave, spanning two million years of prehistory. Changes in vegetation and humidity over time were investigated by means of carbon and oxygen stable isotope analysis on fossil herbivore enamel and ostrich eggshell, creating two independent proxy datasets. The Holocene record was used as a baseline for comparing the Pleistocene sequence, but required chronological tightening. Therefore, nine new radiocarbon dates were obtained, and calibrated and modelled with existing dates to provide a firmer chronology. The ostrich eggshell isotope record suggests arid but variable conditions, with distinct phases of increased humidity in the Early Pleistocene and mid-Holocene. Enamel stable isotope results show clear differences in local resource availability between the Early and Mid-Pleistocene, and then between the Pleistocene and Holocene, with an overall trend of increasing aridity. In
environmental_change case_study cave northern cape south_africa arid interior south_africa lack long continuous well dated climate environmental proxy record compare cultural sequence broad global climate record develops first substantial terrestrial environmental sequence interior southern_africa site cave span prehistory changes vegetation humidity time investigated mean carbon oxygen stable_isotope_analysis fossil herbivore enamel eggshell create two_independent proxy datasets holocene record use baseline compare pleistocene sequence require chronological therefore new radiocarbon_date obtain modelled exist date provide firm chronology eggshell isotope record_suggest arid variable condition distinct phase increase humidity enamel stable_isotope show clear_difference local_resource availability early_mid pleistocene pleistocene holocene overall trend increase aridity