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Datos geocronológicos preliminares de la colisión entre el Gran Arco-Isla Caribeño y la Plataforma Continental de Bahamas en el Segmento de La Española

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Escuder Viruete, J. and Iriondo, Alexander and Premo, W.R. and Pérez Estaún, A. (2004) Datos geocronológicos preliminares de la colisión entre el Gran Arco-Isla Caribeño y la Plataforma Continental de Bahamas en el Segmento de La Española. Geotemas, 6 (1). pp. 177-180. ISSN 1576-5172

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Abstract

In parallel to structural and metamorphlc studies, geochronologlcal Investigations have been initiated in eclogites and blueschists from the Samaná Peninsula complex, northern Hispaniola, using Sm-Nd, UPb, Rb-Sr and 40Ar/39Ar methods, to constraint subduction, collision and exhumation processes in the Caribbean-North America plate boundary zone. A garnet-omphacite- whole rock Sm-Nd isochron from eclogite yields an age of 86±47 Ma (l43Nd/l44Ndinitial= 0,512894±0,000057; MSWD=0,00036). Although imprecise, we interpret this age as dating the peak of eclogitic metamorphism and allows us to calculate an initial eNd value of +7,2, which suggests a relatively depleted source for the protolith and that the rock formed in an intra-oceanic island-arc setting without significant influence from continental crust. Whole rock trace elements and REE data and preliminary Pb and Rb-Sr analyses also support this interpretation. The 40Ar/39Ar analyses of phengite mineral separates from eclogite and blueschist were made to record the cooling age during retrograde metamorphism (Tc»325-3009C). Phengites of eclogite and blueschist yields average plateau ages of 36,30±0,l 3 Ma and 33,85±0,12 Ma, respectively. These Late Eocene to Early Oligocène ages are related to the regional exhumation of the high-P basement complex and are attributed to the initial oblique collision of the Bahama Platform beneath the Hispaniola arc.


Item Type:Article
Uncontrolled Keywords:Blueschist, Eclogite, High-P metamorphism, Caribbean Plate, Geochronology
Subjects:Sciences > Geology > Stratigraphic geology
ID Code:60673
Deposited On:27 May 2020 11:03
Last Modified:27 May 2020 11:03

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