The Pelona-Pico Duarte basalts Formation, Central Hispaniola
Located in Central Hispaniola, the Pelona-Pico Duarte basalts Formation (Fm.) offers an opportunity to study the Late Cretaceous Caribbean large igneous province magmatism on land. It is composed by a ~2.5km-thick pile of massive and monotonous submarine flows of basalts, locally intruded by synvolc...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2011 |
| País: | España |
| Institución: | Universitat Autònoma de Barcelona |
| Repositorio: | Dipòsit Digital de Documents de la UAB |
| Idioma: | inglés |
| OAI Identifier: | oai:ddd.uab.cat:89008 |
| Acceso en línea: | https://ddd.uab.cat/record/89008 https://dx.doi.org/urn:doi:10.1344/105.000001716 |
| Access Level: | acceso abierto |
| Palabra clave: | Caribbean large igneous province Mantle source Hispaniola Caribbean plate |
| Sumario: | Located in Central Hispaniola, the Pelona-Pico Duarte basalts Formation (Fm.) offers an opportunity to study the Late Cretaceous Caribbean large igneous province magmatism on land. It is composed by a ~2.5km-thick pile of massive and monotonous submarine flows of basalts, locally intruded by synvolcanic dikes and sills of dolerite. The Pelona-Pico Duarte basalts Fm. was emplaced onto Turonian-Lower Campanian island-arc volcanic and sedimentary sequences, and is overlain by Maastrichtian platformal carbonates. Two 40Ar/39Ar plateau ages indicate both extrusive and intrusive magmatic activity at least during the 79-68Ma interval (Middle Campanian to Maastrichtian), so the magmas were in part coeval with the late phases of the Caribbean large igneous province. The basalts have a restricted major-and trace-element, and isotopic, compositional variation. For a range of 47.6- 50.2wt.% SiO2, the Pelona-Pico Duarte basalts Fm. has relatively high contents in TiO2 (1.5-3.6wt.%) and Fe2O3T (10.7-13.1wt.%). On the basis of MgO contents, samples can be classified into tholeiitic basalts (<8wt.%) and high-Mg basalts (8-12wt.%). Mineral assemblages and major element compositional trends indicate that basalts derived from tholeiitic parental magmas by fractionation of olivine plus spinel, clinopyroxene and orthopyroxene, observed as microphenocrysts, as well as plagioclase and Fe-Ti oxides. In a MORB-normalized multi-element plot, the basalts have light rare earth elements (LREE) enriched ([La/Nd]N=1.5-2.2) and heavy rare earth elements (HREE) depleted ([Sm/Yb]N=2.1-3.7) patterns, with very high Nb contents (11-30ppm). These patterns and the values of trace element ratios (K/Ba<20, Ti/V. |
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