On the sedimentation of the Molteno sandstones in the vicinity of Molteno, C.P.
Date
1950
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: The sedimentary history of the Molteno Stage is unravelled by investigation of its primary structures and petrographical characteristics. The existence of cyclical sedimentation in the lower 800 - 900 feet due to pulsatory diastrophism in the southern provenance is revealed. Broad "stratigraphic inversion" has taken place during the course of sedimentation of the Molteno sediments and arguments are presented fro including at least the upper Burghersdorp Beds in the molteno Stage. The terrestrial nature of the Molteno Beds is confirmed and depposition is shown to have proceeded under conditions of relatively high precipitation and low mean temperatures. Measurements on cross-bedding prove that the main provenance region lay towards the south , but preliminary study of the feldspars seems to indicate that south-easterly or easterly elevated land played an as yet undetermined role in he production of sediment. Investigation of the feldspars also indicate a progressive upward decrease in acid plagioclase content and an attendant increase in potassium feldspars, and proves the progressive mingling of sedimentary waste from a granitic provenance. Heavy minerals reveal the initial increasing importance of the Dwyka tillarte as a sediment producer and its gradual supersedence by the Witteberg quartzite. Size-distribution analysis is used in an attempt to decipher the control of diastrophism in the southern provenance region on the production of the Molteno sediments.
AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.
AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.
Description
Thesis (M. Sc.) -- University of Stellenbosch, 1959.
Keywords
Sedimentation and deposition, Sandstone -- South Africa -- Molteno, Geology -- South Africa -- Molteno, Dissertations -- Geology, UCTD