Wednesday, 29 August 2007 - 11:50 AM
3.A.C-6
Terrane Correlation between Antarctica, Mozambique & Sri Lanka: Comparisons of Geochronology, Lithology, Structure and Metamorphism
Geoffrey H. Grantham1, Paul H. Macey1, Bernard A. Ingram1, Malcolm P. Roberts2, Richard A. Armstrong3, Tomokazu Hokada4, Kazuyuki Shiraishi4, Avinash Bisnath1, and Vladimiro J. Manhica5. (1) Central Regions Unit, Council for Geoscience, 280 Pretoria Rd, Silverton, P/Bag X112, Pretoria, South Africa, (2) MSSP-Geomap Project, c/o Geological Survey of Papua New Guinea, Port Moresby, Papua New Guinea, (3) RSES, Australian National University, Canberra, Australia, (4) NIPR, Itabashi, Tokyo, Japan, (5) Direcao Nacional Geologia, Maputo, Mozambique
Analysis of lithological, structural, metamorphic and geochronological data from mapping in Mozambique permits recognition of two crustal blocks separated by the Lurio Belt. Comparison of the data, with data from Sri Lanka and Dronning Maud Land (DML) permits recognition of similar blocks in Sri Lanka and DML. Data interpretation suggests they once formed a mega-nappe, comprising part of northern Gondwana, emplaced ~600 km over southern Gondwana during Gondwana amalgamation at ~590-550 Ma. The data suggest deeper levels of erosion in southern Africa compared to Antarctica. It is possible this event extends westwards to the Namibian Damara orogeny with the similar age Naukluft nappes fitting the mega-nappe pattern. Erosional products of the mountain belt are now represented by detrital zircons of 400-700Ma age, seen in sandstone formations of the Transantarctic Mountains, their correlatives in Australia, the Urfjell Group (western DML), the Natal Group and possibly the Cape Supergroup, South Africa.