Observations from the Alpine Tethys and Iberia–Newfoundland margins pertinent to the interpretation of continental breakup
G. Manatschal, O. Müntener, L. L. Lavier, T. A. Minshull, G. Péron-Pinvidic, 2007. "Observations from the Alpine Tethys and Iberia–Newfoundland margins pertinent to the interpretation of continental breakup", Imaging, Mapping and Modelling Continental Lithosphere Extension and Breakup, G. D. Karner, G. Manatschal, L. M. Pinheiro
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Although the Iberia–Newfoundland and Alpine Tethys margins are of different age and ultimately had a different fate, they share remarkable similarities. Both pairs of margins show a change from initially distributed and decoupled extension to later localized, coupled and asymmetric extension that results in thinning of the crust and exhumation of subcontinental mantle. The change in the mode of extension together with the localization of deformation reflects an evolution of the bulk rheology of the extending lithosphere. In this paper we summarize the pertinent geological observations for the Iberia–Newfoundland and Alpine Tethys margins. We describe the stratigraphic evolution, the fault geometry, basin architecture, and magmatic and metamophic evolution of the two pairs of margins from initial rifting to final continental breakup. This description forms a basis for understanding the evolution of the bulk rheology and how the various processes interact during progressive lithospheric extension. For the Iberia–Newfoundland and Alpine Tethys margins initial rifting appears to be controlled by inherited heterogeneities and mechanical localization processes, whereas final rifting and lithospheric rupture is controlled by serpentinization, magmatic and thermal weakening. At other margins, these modes may interact in a different way depending on the prerift conditions and the evolution of the rheology during rifting.
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This book summarizes our present understanding of the formation of passive continental margins and their ocean–continent transitions. It outlines the geological, geophysical and petrological observations that characterize extensional systems, and how such observations can guide and constrain dynamic and kinematic models of continental lithosphere extension, breakup and the inception of organized sea-floor spreading. The book focuses on imaging, mapping and modelling lithospheric extensional systems, at both the regional scale using dynamic models to the local scale of individual basins using kinematic models, with an emphasis on capturing the extensional history of the Iberia and Newfoundland margins. The results from a number of other extensional regimes are presented to provide comparisons with the North Atlantic studies; these range from the Tethyan realm and the northern Red Sea to the western and southern Australian margins, the Basin and Range Province, and the Woodlark basin of Papua New Guinea. All of these field studies, combined with lessons learnt from the modelling, are used to address fundamental questions about the extreme deformation of continental lithosphere.