Paleoproterozoic evolution of the Guiana Shield in Suriname: A revised model

摘要: The Proterozoic basement of Suriname consists a greenstone–tonalite–trondhjemite–granodiorite belt in the northeast country, two high-grade belts northwest and southwest, respectively, large granitoid–felsic volcanic terrain central part punctuated by numerous gabbroic intrusions. is overlain subhorizontal Roraima sandstone formation transected one Jurassic dolerite dyke swarms. Late mylonitisation affected parts basement. Almost 50 new U–Pb Pb–Pb zircon ages geochemical data have been obtained Suriname, much are also available from neighbouring countries. This has led to considerable revision geological evolution main orogenic event Trans-Amazonian Orogeny, resulting southwards subduction later collision between Guiana Shield West African Craton. first phase, 2.18 2.09 Ga, shows ocean floor magmatism, arc development, sedimentation, metamorphism, anatexis plutonism Marowijne Greenstone Belt adjacent older granites gneisses. second phase encompasses Bakhuis Granulite Coeroeni Gneiss through rift-type basin formation, volcanism, sedimentation and, 2.07 2.05 metamorphism. third 1.99 1.95 characterised renewed metamorphism along an anticlockwise cooling path, ignimbritic volcanism extensive varied intrusive magmatism western half country. An alternative scenario discussed, implying origin as active continental margin, recording northwards finally magmatic south northern continent. Grenvillian Laurentia Amazonia around 1.2–1.0 Ga caused widespread mica age resetting