NEIS DE MACUIRA: EVOLUCIÓN TECTÓNICA DE LAS ROCAS METAMÓRFICAS PALEOZOICAS DE LA ALTA GUAJIRA, COLOMBIA
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Universidad Industrial de Santander
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El Neis de Macuira es una unidad metamórfica Paleozoica que aflora en las serranías de Simarua, Jarara y Macuira, Alta Guajira. Se trata de un conjunto litológico que sufrió metamorfismo bajo condiciones de P-T en la facies anfibolita y consta de neises anfibólicos y cuarzo-feldespáticos, anfibolitas, esquistos, pegmatitas, rocas calco-silicáticas y mármoles, con evidencias de migmatización en neises y anfibolitas. En la unidad se observan cinco foliaciones (S1-5) y tres eventos de plegamiento (F1-3) interpretados como producto de dos eventos metamórficos desarrollados en un gradiente metamórfico barroviano progresivo con relaciones P-T intermedias, y relacionados con tectónica de colisión continental. La unidad es importante en el entendimiento de la evolución tectónica de la Alta Guajira y el Caribe debido a que registra diferentes fases deformativas pre-, sin- y post-migmatíticas que podrían relacionarse con diferentes episodios tectónicos: el primero relacionado con la colisión de Laurasia y Gondwana (Orogenia Alleghaniana - Paleozoico Tardío) y el segundo relacionado con la evolución de la Placa Caribe (Orogenia Andina - Meso a Cenozoico).
Palabras clave: Migmatitas, Deformación, Orogenia Alleghaniana, Alta Guajira, Colombia
The Macuira Gneiss is a Paleozoic metamorphic unit that outcrops in the Simarua, Jarara and Macuira ranges, Alta Guajira. It is composed by a lithologies metamorphosed under amphibolite facies P-T conditions and consist of amphibolitic and quartz feldspathic gneisses, amphibolites, schists, pegmatites, calc-silicated rocks and marbles, with migmatization evidences in gneisses and amphibolites. Five foliations (S1-5) and three folding events (F1-3) were identified and interpreted as product of two metamorphic events, developed in a progressive barrovian metamorphic gradient of intermediate pressure with intermediate P-T ratio, interpreted as product of continental collision tectonics. This unit is important in understanding of the tectonic evolution of the Alta Guajira and Caribbean because it records different deformational phases pre-, syn- and post-migmatitic, that could be related with different tectonic episodes: the first associated with the collision between Laurasia and Gondwana (Alleghanian Orogeny - Late Paleozoic), and the second related with the Caribbean Plate evolution (Andean Orogeny - Meso-Cenozoic). Keywords: Migmatites, Deformation, Alleghanian orogeny, Alta Guajira, Colombia.
The Macuira Gneiss is a Paleozoic metamorphic unit that outcrops in the Simarua, Jarara and Macuira ranges, Alta Guajira. It is composed by a lithologies metamorphosed under amphibolite facies P-T conditions and consist of amphibolitic and quartz feldspathic gneisses, amphibolites, schists, pegmatites, calc-silicated rocks and marbles, with migmatization evidences in gneisses and amphibolites. Five foliations (S1-5) and three folding events (F1-3) were identified and interpreted as product of two metamorphic events, developed in a progressive barrovian metamorphic gradient of intermediate pressure with intermediate P-T ratio, interpreted as product of continental collision tectonics. This unit is important in understanding of the tectonic evolution of the Alta Guajira and Caribbean because it records different deformational phases pre-, syn- and post-migmatitic, that could be related with different tectonic episodes: the first associated with the collision between Laurasia and Gondwana (Alleghanian Orogeny - Late Paleozoic), and the second related with the Caribbean Plate evolution (Andean Orogeny - Meso-Cenozoic). Keywords: Migmatites, Deformation, Alleghanian orogeny, Alta Guajira, Colombia.