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Detailed Reference Information |
Marques, F.O., Ribeiro, A. and Munhá, J.M. (1996). Geodynamic evolution of the Continental Allochthonous Terrane (CAT) of the Bragança Nappe Complex, NE Portugal. Tectonics 15: doi: 10.1029/95TC03852. issn: 0278-7407. |
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The Bragan¿a Massif, in particular its Continental Allochthonous Terrane (CAT), is a keystone in the comprehension of the pre-Variscan and Cariscan geodynamic evolution of the Eurasian plate, in particular of the high-grade metamorphic evolution. The Braganca CAT comprises three types of granulites (recording quite distinct metamorphic histories) and paragneisses with enclosed eclogite boudins. It has undergone five characterizable, main deformation phases during two orogenic cycles, separated by the extensive intrusion of mafic/ultramafic layered bodies (types 2 and 3 granulites) into a pervasively deformed granulitic lower continental crust (type 1 granulites). Geochronological data obtained on high-grade metamorphic rocks from Braganca and other similar rocks in the Variscan fold belt have been typically interpreted in two different ways: polycyclical evolution, Precambrian and Paleozoic (Variscan), or monocyclical evolution (Variscan). This second hypothesis is in clear contraction with field evidence, with tectonometamorphic data, and even with some geochronological data, as shown in this article. Thus we suggest that the tectonometamorphic evolution of the Braganca CAT, and, by comparison, of other similar CAT in the Variscan fold belt, took place during two orogenic cycles, one Precambrian (Grenvillian? Pan-African/Cadomian?) and another one Paleozoic (Variscan). ¿ American Geophysical Union 1996 |
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Abstract |
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Keywords
Tectonophysics, Continental tectonics—general, Tectonophysics, Evolution of the Earth, Tectonophysics, Plate motions—past |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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