Data/hora: 15/06/2024 02:06:30

Provedor de dados: 	5	
País: 	France	
Título: 	The opening of the Indian Ocean : what is the impact on the East African, Madagascar and Antarctic margins, and what are the origins of the aseismic ridges ?	
Autores: 	Thompson, Joseph Offei.	
Data: 	2017-11-21	
Ano: 	2017	
Resumo: 	Gondwana, formed during the Pan-African Orogeny between 720 and 550Ma, composed of Archean and Paleoproterozoic Cratonic cores surrounded by accreted progressively younger terrains of Mesoproterozoic and Neoproterozoic age. The event saw the closure of a number of large ocean basins and the collision of several cratonic blocks to form the largest unit of continental crust (Pangea) on earth for more than 200Ma from the Late Neoproterozoic 550 Ma to the Carboniferous at about 320 Ma. Its subsequent fragmentation has been a subject of several studies over the past five decades, yet the very important question of the initial geometry of the super-continent remains enigma. Current reconstruction models of the Indian Ocean are characterized by large gaps, overlaps and misfits of major structural and cratonic bodies in full-fit reconstruction, and positions of tectonic blocks that are inconsistent with field observations, a phenomenon sustained by inadequate data, long standing debates and lack of consensus on the nature of major structures and basins in the ocean domain. Past attempts to reconstruct the ocean has led to varied and complex models, with their own logic and different geographical limits, whose validity and underlying assumptions require testing in the light of current global geological and geophysical data. Examination of these models and their consequences on the continental passive margins brings to light critical scientific questions they pose, and the incoherencies that exist between them in their initial fit. This work presents a comprehensive study of the structure of the Precambrian basement, Paleozoic marginal and rift basins of all the plates surrounding the Indian Ocean, examine the architecture and geochronological composition of their composing cratons and crustal blocks, and delineating important structural markers in order to accurately juxtapose them in the initial fit. We introduce a new holistic model of Gondwana’s evolution achieved through a combination of onshore and offshore geological and geophysical data published integrated with newly acquired during the Pamela MOZ3-5 campaign. Our new model is coherent with current data interpretations in the Indian Ocean, and is consistent with all existing knowledge about major structures constituting Gondwana. The model permits full extent of major cratonic, volcanic and sedimentary structures within the super-continent, and presents the best candidate at present day upon which further work could be carried.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	http://archimer.ifremer.fr/doc/00415/52637/53483.pdf

http://archimer.ifremer.fr/doc/00415/52637/53484.pdf

http://archimer.ifremer.fr/doc/00415/52637/	
Editor: 	Université de Rennes	
Formato: 	application/pdf	
Fonte: 	2017 Université de Rennes

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