The Lower Palaeozoic palaeogeographical evolution of the northeastern and eastern peri-Gondwanan margin from Turkey to New Zealand
Trond H. Torsvik, L. Robin M. Cocks, 2009. "The Lower Palaeozoic palaeogeographical evolution of the northeastern and eastern peri-Gondwanan margin from Turkey to New Zealand", Early Palaeozoic Peri-Gondwana Terranes: New Insights from Tectonics and Biogeography, M. G. Bassett
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In Lower Palaeozoic times, Gondwana was by far the largest tectonic entity, stretching from the South Pole to north of the Equator, and is termed a superterrane. We consider the northeastern sector of the Gondwanan and peri-Gondwanan margin, from Turkey through the Middle East, the north of the Indian subcontinent, southern China and SE Asia, to Australia and New Zealand. There was progressive tectonic activity along some of its margins during the period, with areas such as southeastern Australia undergoing enlargement through the accretion of island arcs as that part of Gondwana rotated. However, most of the area, from the Taurides of Turkey to at least east of India, represented a passive margin for the whole of the Lower Palaeozoic. Other adjacent areas, such as the Pontides of Turkey and Annamia (Indochina), were separate from the main Gondwanan craton as independent terranes. The quality and quantity of available data on Lower Palaeozoic rocks and faunas varies enormously over different parts of this substantial area, and there are few or no detailed palaeomagnetic data available for most of it. Some workers have considered the string of terranes from Armorica to the Malaysia Peninsula as having left Gondwana together in the late Cambrian as a Hun superterrane, leaving a widening Palaeotethys Ocean between it and Gondwana. However, we consider that the Palaeotethys opened no earlier than in late Silurian time (with Armorica and other terranes to its north), and that the Hun superterrane was not a cohesive unity. Other researchers vary in presenting many substantial Central Asian and Far Eastern terranes, including North China, South China, Tarim, Annamia and others, as integral parts of core Gondwana and not leaving it until Devonian and later times. We conclude that North China, Tarim and Annamia, among others, were probably not attached to core Gondwana in the Lower Palaeozoic, that South China was close to Gondwana (but not an integral part of it), and that Sibumasu was probably part of Gondwana. We try to reconcile the very varied published geological data and opinions, and present new palaeogeographical maps for that sector of Gondwana and surrounding areas for the Cambrian (500 Ma), Ordovician (480 Ma) and Silurian (425 Ma).
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Following the late Neoproterozoic – early Cambrian breakup of the supercontinent Rodinia, Gondwana evolved as one of the principal continental masses on Earth, embracing most of South America, Africa, Australasia, Antarctica, much of western Europe and parts of Asia. Around its margins were various other terranes that had varying tectonic and biogeographical affinities with the main continental block. This book incorporates a series of reviews and multidisciplinary research papers that together explore the tectonic, palaeogeographical and palaeobiogeographical evolution of the elements that made up the peri-Gondwanan collage. The stratigraphical scope of the coverage embraces the late Precambrian through early Devonian, providing a comprehensive overview of structural, stratigraphical and biological evolution through this significant interval of Earth history. Integration of these various processes throughout the volume will be of broad-based interest to a wide range of geoscientists.