The Palaeozoic palaeogeography of central Gondwana
Trond H. Torsvik, L. Robin M. Cocks, 2011. "The Palaeozoic palaeogeography of central Gondwana", The Formation and Evolution of Africa: A Synopsis of 3.8 Ga of Earth History, D. J. J. Van Hinsbergen, S. J. H. Buiter, T. H. Torsvik, C. Gaina, S. J. Webb
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Nine new palaeogeographical maps of central Gondwana are presented at intervals within the Palaeozoic from the Middle Cambrian at 510 Ma to the end of the Permian at 250 Ma. The area covered includes all of Africa, Madagascar, India and Arabia as well as adjacent regions, including parts of southern Europe, much of South America (including the Falkland Isles) and Antarctica. After final assembly in the Late Neoproterozoic the southern margin was largely passive throughout the Palaeozoic, apart from some local orogeny in the Cambrian in the final stages of the largely Neoproterozoic Pan-African Orogeny and during the Late Palaeozoic Gondwanide Orogeny. The northern peri-Gondwana margin was active during the Early Palaeozoic but the NW part became passive by the earliest Ordovician when the Rheic Ocean opened between Gondwana and Avalonia. This was eventually followed by the latest Silurian or Early Devonian opening of the Palaeotethys Ocean between Gondwana and Iberia, Armorica and associated terranes and, much later, the rifting and opening of the Neotethys Ocean near the close of the Permian. In the Late Carboniferous, Gondwana merged with Laurussia to form Pangea. That accretion took place outside the area to the NW, although the consequent orogenic activity extended to Morocco and Algeria. Most of the centre of Gondwana was land throughout the Palaeozoic but with extensive shelf seas over the craton margins, particularly the northern margin from the Cambrian to the Devonian on which the important north African and Arabian hydrocarbon source rocks were deposited in the Lower Silurian (with the chief reservoirs in the adjacent Upper Ordovician) and Upper Devonian. There were also substantial Upper Carboniferous and later non-marine lake basins in central and southern Africa in which the Karroo Supergroup was deposited. The South Pole was located within the area from the Early Palaeozoic to the Mid-Permian and central Gondwana was therefore greatly affected by two ice ages: the short but sharp Hirnantian glaciation at the end of the Ordovician and another lasting sporadically for more than 25 Ma during the later Carboniferous and Early Permian.
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The African continent preserves a long geological record that covers almost 75% of Earth’s history. The Pan-Africanorogeny (c.600–500—Ma) brought together old continental kernels (West Africa, Congo, Kalahari and Tanzania) to form Gondwana and subsequently the supercontinent Pangaea by the late Palaeozoic. The break-up of Pangaea since the Jurassic and Cretaceous, primarily through opening of the Central Atlantic, Indian, and South Atlantic oceans, in combination with the complicated subduction history to the north, gradually shaped the African continent.
This volume contains 18 contributions that discuss the geology of Africa from the Archaean to the present day. It celebrates African geology in two ways: first, it highlights multidisciplinary Earth science research by viewing the formation and evolution of Africa from 18 different angles; second, it celebrates the work of Kevin Burke and Lewis Ashwal and portrays the wide range of interests and research angles that have characterized these two scientists throughout their careers, working in Africa, and studying African geology.