Ice sheet deformation in the Table Mountain group, Western Cape

• Main Author: Blignault, H. J.
• Other Authors: Stellenbosch University. Faculty of Science. Department of Earth Sciences.
• Format: Thesis
• Language: English
• Published: Stellenbosch : Stellenbosch University 1970
• Subjects: Folds (Geology) > South Africa > Western Cape; Geology > South Africa > Western Cape; Table Mountain Group (South Africa); Rock deformation > South Africa > Westerns Cape; Ice sheets > South Africa > Western Cape; Cape Geology; Maak; Table Mountain; Ice Sheet
• Online Access: http://hdl.handle.net/10019.1/98996

Thesis (MSc)--Stellenbosch University, 1970. Maps may be of poor quality due to digitisation process. ENGLISH ABSTRACT: The Lower Paleozoic glaciogenic sediments of the Table Mountain Group are interpreted as the result of two ice sheet advances into the active Table Mountain embayment. Subglacial deformation during the first advance gave rise to the Fold Zone. Macro- and micro-fabric data of deformed and undeformed sediments provide valuable constraints on the interpretation of the rheology of sediment transport media and the contemporaneously deformed sediments. It is shown that the structural characteristics of the Fold Zone are consistent with the progressive infill of the Table Mountain embayment by an ice sheet. The distribution, size and geometry of the folds are dependent on the effective load of the ice sheet and the type and direction of ice sheet flow; compressive and extending flow resulted in pure shear and simple shear deformation respectively. AFRIKAANSE OPSOMMING: Die glasiogene sedimente van die Onder-Paleosolese Tafelberggroep word verklaar as die sedimentasie-produk van twee ysplaatbewegings in die aktiewe Tafelberginham. Die Plooisone word geassosieer met onderysplaatdeformasie tydens die eerste ysplaatbeweging. Die rheologie van die sedimentasietransportmedia en die gedeformeerde sedimente van die Plooisone is ondersoek deur gebruik te maak van maakselanalises. 'n Model is opgestel waarvolgens die struktuur van die Plooisone ooreenstem met die progressiewe opvulling van die Tafelberginham deur 'n ysplaat. Hiervolgens is die verspreiding, grootte en geometrie van die plooie 'n funksie van die effektiewe ysplaatbelading en tipe en rigting van ysplaatvloei; kompressiewe en verlengingsvloei het oorlangse en eenvoudige skuifskeurvervorming respektiewelik veroorsaak.