The stratigraphy of the Witteberg-Dwyka contact beds
Date
1967
Authors
Loock, J C
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Effective use is made of a multiple system to subdivide the
portion of the Cape-Karroo stratigraphical column investigated into
rock, time and in a lesser degree, biostratigraphic units.
Heavy mineral studies reveal that distinct vertical variation
trends exist for tourmaline. The steady increase in the frequency
of brown tourmaline over other types makes this mineral specially
suited for correlation, even over long distances.
Garnet is indicative of the Dwyka Group.
In the southern outcrop areas the Cape and Karroo Supergroups
are structurally conformable to each other.
Continuity in deposition was the rule.
The sandstones of the Wittepoort Formation are interpreted as stable
shelf deposits. The mixed sediments of the Lake Mentz Formation
mark the rapid transition to a large interior basin with more restricted
circulation. The fine-grained proglacial sediments of the
Kommadagga Formation were deposited in a basin inherited from the
Witteberg Epoch. The overlying tillites were deposited in a marine
environment. An interpretation of the tectonic history of the Cape-
Karroo sequence indicates that a peneplanation stage was present up
to the end of the Witteberg Epoch. A geosynclinal stage then set in.
It is convenient to divide the sequence into two major timestratigraphic
units of system rank. The base of the Karroo System is
chosen in view of historical, lithological, geographical and paleontological
considerations.
Description
Thesis submitted in partial fulfillment of the requirements
for the degree Of M.Sc. in Geology at the
University of Stellenbosch
Keywords
Statigraphy