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| Titel |
The Late Pleistocene and Holocene palaeoenvironmental context of Wonderwerk Cave in the southern Kalahari, South Africa |
| VerfasserIn |
Louis Scott, Margaret Avery, Marion Bamford, Francesco Berna, James Brink, George Brook, Michael Chazan, Michaela Ecker, Yolanda Fernandez-Jalvo, Paul Goldberg, Julia Lee-Thorp, Lloyd Rossouw, Francis Thackeray, Liora Horwitz |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093446
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| Publikation (Nr.) |
 EGU/EGU2014-8166.pdf |
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| Zusammenfassung |
| Wonderwerk Cave, located in the arid southern Kalahari in South Africa, is an exceptional
site, since it preserves a two million year long record of human occupation. While research on
older levels in various excavation sections of the cave deposits is ongoing, we focus here on
the younger levels that span the last 35,000 years. We present the results of past and recent
work on zooarchaeology, macrobotany, palynology, phytoliths, stable isotopes,
micromorphology and speleothem growth, which track marked diachronic environmental
fluctuations.
Except for a hiatus of ~33–23 ka, growth and isotope data for a speleothem near
the cave entrance suggests moist conditions from ~35-33, and ~22-14 ka with
brief, dry episodes at ~34, ~22 and ~15 ka. Temperatures were cool except for an
increase ~16-14 ka after which cold conditions equivalent to the Younger Dryas
event occurred. In Stratum 5 (>12.5 ka in Excavation 1), relatively low carbon
isotope (δ13C) values, pollen in the speleothem, and pollen in dung deposits indicate
that the vegetation included a large C3 component during this phase. While the
climate experienced sharp fluctuations in moisture when stalagmite growth was
interrupted, more severe drying occurred by ~12 ka as indicated by dung pollen.
Pollen in Stratum 4d (undifferentiated by stratum sub-phases) suggest that warmer
grassy conditions developed before 11 ka, which is supported by δ13C values in
OES that suggest a greater C4plant component in Stratum 4dII associated with
the Oakhurst-like archaeological industry. Undifferentiated Stratum 4d indicates
moderate moisture availability (pollen) but sub-phase 4dII suggest drying (OES
δ18O).
C3-presence (OES δ13C) in the vegetation became stronger again in Stratum
4dI (Oakhurst) and Stratum 4cII (Wilton). This is supported by Asteraceae pollen
especially ~8.5 ka. Except for a fluctuation in OES δ18O values in Stratum 4cII, δ18O
and pollen and micromammal composition suggest progressive aridity until ~6 ka
(Stratum 4bII). δ18O values on OES indicate a marked shift to a moister episode in the
mid-Holocene between 5.9 and 4.9 ka while pollen, phytoliths and microfauna indicate that
more grassy vegetation with woodland developed ~5.5-4.4 ka (Strata 4bI-4aLH,
Wilton).
A trend towards more arid conditions culminated ~2.8-1.2 ka (Strata 3a-2b, the
Ceramic Later Stone Age) as suggested by oxygen and carbon isotopes in OES, and is
consistent with pollen and phytolith data indicating vegetation with C4 grasses. The
macrofaunal data corroborate this picture, with grassland environments increasing
through the Holocene as reflected in an increase in grazers; frequencies of springbok
(Antidorcas marsupialis), a species that suggests aridity, rises from 0% in the early
Holocene, to 10% in the mid-Holocene, and further to 16% in the Late Holocene. The
general arid trend has continued until a slight increase in moisture availability ~0.8
ka leading up to modern semi-arid conditions in the uppermost disturbed strata. |
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