U-Pb Geochronology of detrital zircons from the Venezuelan passive margin : implications for an Early Cretaceous Proto-Orinoco river system and Proto-Caribbean ocean basin paleogeography
Noguera, Mariela (Swift Energy Operating)
Wright, J. E. (University of Georgia. Department of Geology)
Urbani, F. (Universidad Central de Venezuela)
Pindell, J. (Rice University Keith-Weiss Geological Laboratory. Department of Earth Science)

Data:	2011
Resum:	The Guyana Shield has long been interpreted as the source of siliciclastic detritus within the Cretaceous passive margin strata of northern Venezuela. We have determined U-Pb ages of detrital zircons separated from Early Cretaceous strata of the passive margin. Although the Guyana shield is the probable source for much of the Archean, Paleoproterozoic and early Mesoproterozoic detrital zircon grains, there is a prominent age population (ca. 0. 95-1. 2Ga) that is not easily explained as being derived from the shield. A western source in the Venezuelan and/or northern Colombian Andes is suggested for this detrital component. We propose that a Proto-Orinoco river system drained both the Guyana Shield and the Venezuelan and Colombian Andes and that branches of this river system were funneled through Triassic/Jurassic rift basins that formed during initial opening of the Proto- Caribbean Seaway. The detrital zircon age data have implications for paleogeographic reconstructions of the Caribbean region prior to the breakup of Pangea and the longevity of continental scale river systems.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Detrital Zircon ; Passive Margin ; Venezuela
Publicat a:	Geologica acta, Vol. 9, Núm. 3-4 (setembre-desembre 2011) , p. 265-272, ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/247921
DOI: 10.1344/105.000001698

22 p, 760.5 KB

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