Biesiespoort revisited: a case study on the relationship between tetrapod assemblage zones and Beaufort lithostratigraphy south of Victoria West
Date
2018-12
Authors
Day, Michael O.
Rubidge, Bruce S.
Journal Title
Journal ISSN
Volume Title
Publisher
Evolutionary Studies Institute
Abstract
The relationship between the tetrapod assemblage zones of the South African Karoo Basin and the lithostratigraphic divisions of the
Beaufort Group is well-established, and provides an independent means of dating fossil occurrences. However, this relationship may
not be consistent across the basin; a discrepancy exists between the historical tetrapod assemblages in the vicinity of Victoria West,
Northern Cape Province, and the expected tetrapod assemblage zones based on mapped geology. In order to examine this disconnect,
we collected fossils at two localities close to Biesiespoort railway station, a locality that was visited on a number of occasions by Robert
Broom. Our fossil samples support the biostratigraphic determinations of Broom and thus confirmthat the stratigraphic extent of the
biozones at these localities differs from their type areas further south. The reasons for this are unclear but could be related to the northward
younging of the lithological units, implying complex depositional processes, or result from difficulties in mapping. Nevertheless,
caution should be exercised when using mapped geology near Victoria West as a guide to the age of fossils found there.
Description
Keywords
Tropidostoma, Cistecephalus, biostratigraphy, Karoo, Beaufort Group, Victoria West