Variaciones petrológicas del batolito surpatagónico entre los 47.5°-48° sur: XI región de Aysén, Chile
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2017
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es
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Universidad Andrés Bello
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Licencia CC
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Resumen
El Batolito Patagónico se encuentra a lo largo de los Andes Australes de Chile entre las latitudes 40° y 56° S, donde se presenta como un cordón continuo norte-sur en casi toda su extensión, cambiando a este-oeste en su parte más austral. El batolito se divide en tres segmentos: el Batolito Norpatagónico (40°-47° S), Batolito Surpatagónico (47°-53° S) y el Batolito Fueguino (53°-56° S) (Hervé et al.,2007). En el presente trabajo se estudiará el Batolito Surpatagónico a través de una transecta este-oeste al sur del Golfo de Penas, entre las latitudes 47.5° y 48° S.
Los resultados de estudios petrográficos de 25 muestras obtenidas del Batolito Surpatagónico corresponden a: 5 granitos, 1 pórfido riodacítico, 2 granodioritas, 11 tonalitas, una cuarzodiorita, 1 diorita, 3 gabros y 1 microbrecha tectónica. Sus principales texturas son fanerítica, glomerofírica, poikilítica, simplectíticas y de reemplazo. Sus fases minerales primarias corresponden a cuarzo, plagioclasa, feldespato potásico, anfíbola, biotita, clinopiroxeno y olivino, junto con minerales opacos. Las fases minerales secundarias son clorita, epidota, sericita, arcillas, y en ocasiones titanita.
La presencia de anfíbola y biotita en casi todas las muestras, suponen sus génesis relacionadas a la cristalización de magmas hidratados.
En base a su distribución geográfica se proponen dos dominios litológicos, los cuales son: el dominio granítico emplazado en la parte oriental del batolito y el dominio tonalítico en la parte central. Además, observando las edades de estudios anteriores se distinguen dos hiatus magmáticos: entre los 48 y 80 Ma y entre los 48 y 25 Ma. Las rocas Cretácicas se encuentran dispuestas a lo largo de toda la transecta, lo que supone que el arco Cretácico tiene un ancho de más de 150 km en esa latitud.
The Patagonian Batholith is found along the Southern Andes of Chile between latitudes 40 ° and 56 ° S, where it presents as a continuous cord north-south in almost all its extension, changing east-west in its southern part. The batholith is divided into three segments: the North-Patagonian Batholith (40 ° -47 ° S), the South-Patagonian Batholith (47 ° -53 ° S) and the Fuegian Batholith (53 ° -56 ° S) (Hervé et al., 2007). In the present work, the South-Patagonian Batholith will be studied through an east-west transect south of the Golfo de Penas, between latitudes 47.5° and 48° S. The results of petrographic studies of 25 samples obtained from the South-Patagonian Batholith correspond to: 5 granites, 1 riolite porphyry, 2 granodiorites, 11 tonalites, 1 quartz diorite, 1 diorite, 3 gabbros and 1 tectonic microbreccia. Its main textures are faneritic, glomerofiric, poikilitic, symplectite and replacement. Its primary mineral phases correspond to quartz, plagioclase, potassium feldspar, amphibole, biotite, clinopyroxene and olivine, together with opaque minerals. The secondary mineral phases are chlorite, epitope, sericite, clays, and sometimes titanite. The presence of amphibole and biotite in almost all samples, suppose their genesis related to the crystallization of hydrated magmas. Based on its geographical distribution, two lithological domains are proposed, which are: the granite domain located in the eastern part of the batholith and the tonalite domain in the central part. In addition, observing the ages of previous studies distinguish two magmatic hiatuses: between 48 and 80 Ma and between 48 and 25 Ma. Cretaceous rocks are arranged along the entire transect, which means that the Cretaceous arc has a width of more than 150 km in that latitude.
The Patagonian Batholith is found along the Southern Andes of Chile between latitudes 40 ° and 56 ° S, where it presents as a continuous cord north-south in almost all its extension, changing east-west in its southern part. The batholith is divided into three segments: the North-Patagonian Batholith (40 ° -47 ° S), the South-Patagonian Batholith (47 ° -53 ° S) and the Fuegian Batholith (53 ° -56 ° S) (Hervé et al., 2007). In the present work, the South-Patagonian Batholith will be studied through an east-west transect south of the Golfo de Penas, between latitudes 47.5° and 48° S. The results of petrographic studies of 25 samples obtained from the South-Patagonian Batholith correspond to: 5 granites, 1 riolite porphyry, 2 granodiorites, 11 tonalites, 1 quartz diorite, 1 diorite, 3 gabbros and 1 tectonic microbreccia. Its main textures are faneritic, glomerofiric, poikilitic, symplectite and replacement. Its primary mineral phases correspond to quartz, plagioclase, potassium feldspar, amphibole, biotite, clinopyroxene and olivine, together with opaque minerals. The secondary mineral phases are chlorite, epitope, sericite, clays, and sometimes titanite. The presence of amphibole and biotite in almost all samples, suppose their genesis related to the crystallization of hydrated magmas. Based on its geographical distribution, two lithological domains are proposed, which are: the granite domain located in the eastern part of the batholith and the tonalite domain in the central part. In addition, observing the ages of previous studies distinguish two magmatic hiatuses: between 48 and 80 Ma and between 48 and 25 Ma. Cretaceous rocks are arranged along the entire transect, which means that the Cretaceous arc has a width of more than 150 km in that latitude.
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Tesis (Geólogo)
Palabras clave
Petrología, Chile, Investigaciones, Decimoprimera Región