| Summary: | Palaeomagnetic analysis indicates that Haasgat, a fossil-bearing palaeocave in the Gauteng Province of
South Africa, is dominated by reversed magnetic polarity in its oldest, deepest layers and normal polarity in
the younger layers. The presence of in-situ
Equus
specimens suggests an age of less than ~2.3 Ma, while
morphological analysis of faunal specimens from the ex-situ assemblage suggests an age greater than
1.8 Ma. Given this faunal age constraint, the older reversed polarity sections most likely date to the beginning
of the Matuyama Chron (2.58–1.95 Ma), while the younger normal polarity deposits likely date to the very
beginning of the Olduvai Sub-Chron (1.95–1.78 Ma). The occurrence of a magnetic reversal from reversed
to normal polarity recorded in the sequence indicates the deposits of the Bridge Section date to ~1.95 Ma.
All the in-situ fossil deposits that have been noted are older than the 1.95 Ma reversal, but younger than
2.3 Ma. Haasgat therefore dates to an interesting time period in South African human evolution that saw
the last occurrence of two australopith species at ~2.05–2.02 Ma (Sts5
Australopithecus africanus
from
Sterkfontein Member 4) to ~1.98 Ma (
Australopithecus sediba
from Malapa) and the first occurrence of
early
Homo
(Sk847),
Paranthropus
and the Oldowan within Swartkrans Member 1 between ~2.0 Ma and
~1.8 Ma.
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