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Magmatic and geotectonic significance of Santa Elena Peninsula, Costa Rica

Show simple item record Gazel, E. Denyer, P. Baumgartner, P. O. 2016-10-31T16:56:20Z 2016-10-31T16:56:20Z 2006
dc.identifier.citation Denyer, P.; Baumgartner, P.O.; Gazel, E.; (2006). Magmatic and geotectonic significance of Santa Elena Peninsula, Costa Rica. Geologica Acta: an international earth science journal, Sin mes, 193-202. es_CR
dc.identifier.issn 1695-6133
dc.identifier.uri 10.1344/105.000000365
dc.description.abstract We present a new integrated interpretation of the geochemistry and geotectonic significance of the Santa Elena Peninsula, which is divided in three units: 1) an overthrust allocthonous unit of ultramafic and mafic rocks, the Santa Elena Nappe; 2) an autochthonous basaltic sedimentary suite, resting immediately below the overthrust, the Santa Rosa Accretionary Complex; and 3) Islas Murciélago pillow and massive basaltic flows. In the Santa Elena Nappe three petrological affinities have been recognized: 1) the ultramafic complex, that corresponds to depleted (MORB-like) mantle serpentinizated peridotites, with very low TiO2 and high Ni and Cr; 2) the pegmatitic gabbros, layered gabbros and plagiogranites and basaltic dikes with low TiO2 ( 0.89%) contents and high LREE depletions; and 3) the doleritic dykes with higher TiO2 (0.89%). These mafic associations have geochemical signatures that suggest an island arc origin and petrographic evidences of low grade metamorphism and hydrothermal alteration. The Santa Rosa Accretionary Complex includes pelagic and volcanoclastic sediments, tuffs and alkaline magmatic rocks, originated by low degree melting of enrichment OIB mantle source, and probably related with seamount portions incorporated into the accretionary prism. Islas Murciélago pillow and massive basalts show no clear structural relationship with the rest of the units, but are geochemically similar to the dolerites of the Santa Elena Nappe. Sr, Nd, and Pb isotopic ratios of the Santa Elena Nappe and the Santa Elena Accretionary Complex samples do not correspond to the Galapagos Mantle array, and have different mantle reservoirs and geochemical characteristics than the Nicoya Complex. es_CR
dc.language.iso en_US es_CR
dc.publisher Geologica Acta es_CR
dc.subject Santa Elena Peninsula es_CR
dc.subject Oceanic assemblages es_CR
dc.subject Ultramafic Complex es_CR
dc.subject Geochemistry es_CR
dc.subject Accretionary complex es_CR
dc.title Magmatic and geotectonic significance of Santa Elena Peninsula, Costa Rica es_CR
dc.type Article es_CR

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