Includes bibliographical references (leaves 89-102). / A petrological and metamorphic comparison of Mesoproterozoic metabasic rocks on the easern margin of the Archaean Grunehogna Craton and the adjacent Maud Belt in western Dronning Maud Land, East Antarctica, revealed a difference in peak metamorphic conditions from T = ~275° to 730°C and P=2 to 10.7 kbar over a distance of only 30 km across a major glacial valley. The lower grade constraints were derived from average P-T calculations using THER-MOCALC and thermodynamic modeling of phase equilibria together with chlorite geothermometry. The high-grade P-T constraint for the westernmost part of the Maud Belt closest to the glacier, derived from hornblende-plagioclase thermometry and geobarometric calculations with a garnet amphibolite assemblage, is very similar to that reported for the eastern Maud Belt and, therefore, does not support the concept of a westward decreasing metamorphic field gradient as previously proposed. In conjunction with a recent geochronological study on the eastern Maud Belt, this study suggests that the inferred sub-glacial boundary between the Grunehogna Craton and the Maud Belt, known as the Pencksökket-Jutulstraumen Discontinuity, may represent a major thrust that developed during Pan-African orogenesis (possibly as the continuation of the East African Mozambique Belt into East Antarctica) prior to extension and its development as a normal listric fault or succession of fault slices during the Mesozoic break-up of Gondwana.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uct/oai:localhost:11427/4199 |
| Date | January 2005 |
| Creators | Grosch, Eugene Gerald |
| Contributors | Frimmel, Hartwig E |
| Publisher | University of Cape Town, Faculty of Science, Department of Geological Sciences |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Master Thesis, Masters, MSc |
| Format | application/pdf |
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