Geometry and kinematics of Seno Arcabuz Shear Zone, Patagonian Andes, Chile.
Geometria y cinematica de la Zona de Cizalle Seno Arcabuz, Andes patagonicos, Chile.
| dc.contributor | en-US | |
| dc.contributor | es-ES | |
| dc.creator | Olivares, Beatriz | |
| dc.creator | Cembrano, Jose | |
| dc.creator | Herve, Francisco | |
| dc.creator | Lopez, Gloria | |
| dc.creator | Prior, David | |
| dc.date | 2010-06-29 | |
| dc.identifier | http://www.andeangeology.cl/index.php/revista1/article/view/V30n1-a03 | |
| dc.identifier | 10.5027/andgeoV30n1-a03 | |
| dc.description | Metamorphic units of different age and structural levels occur at Isla Diego de Almagro (51°30'S), where they are juxtaposed by the Seno Arcabuz Shear Zone (SASZ). The SASZ strikes NNW and exposes deeper structural levels to the west of it. The SASZ rocks are ductilely deformed and document, at least, two deformation events evidenced by coexistent superposed fabrics. An early mylonitic foliation and lineation, and a late low strain foliation and lineation originated by folding of the early fabric. The mylonitic lineation is well preserved and plunges moderately to the north (ca. 40°); the rock strain and metamorphic grade increase progressively to the south. Ductile deformation is triclinic, as documented by oblique stretching lineations, typical of transpressional shear zones. Kinematic indicators, which are mainly sinistral-reverse, are consistent with bulk transpressional kinematics. According to field geology, shear zone kinematics and available geologic and chronologic data, two possible scenarios are proposed to account for the spatial relationship between the SASZ and the two different structural levels juxtaposed by it: (1) The SASZ is coeval with the differential exhumation of the western block, and then the north-plunging lineations formed during sinistral-reverse motion or (2) The SASZ is not coeval with differential exhumation of the western block, in such case the mylonitic lineation formed in a formerly sinistral strike-slip shear zone and the exhumation of the western block took place later, by block tilting to the north. | en-US |
| dc.description | La Zona de Cizalle Seno Arcabuz (ZCSA) de rumbo general nornoroeste yuxtapone dos unidades de rocas metamorficas de distintas edades y niveles estructurales en la isla Diego de Almagro (51°15'-51°40'S): una unidad occidental, de facies esquistos verdes y esquistos azules; y otra unidad oriental, de rocas metasedimentarias. Las rocas de la ZCSA estan deformadas ductilmente y presentan, al menos, dos eventos de deformacion documentados por sendas fabricas coexistentes y sobrepuestas: una foliacion y lineacion milonitica tempranas y una foliacion y lineacion de bajo 'strain' tardias originadas por plegamiento de la fabrica milonitica. La lineacion milonitica esta bien preservada y posee buzamiento general hacia el norte (~40°). El grado metamorfico de la deformacion corresponde a la facies esquistos verdes y se incrementa hacia el sur donde se encuentran rocas de mas alto 'strain'. La deformacion ductil es de naturaleza triclinica, evidenciada por una lineacion de estiramiento oblicua la que es tipica de zonas de cizalle transpresionales. Asi lo corroboran los indicadores cinematicos, principalmente sinistrales inversos. Se proponen y discuten dos diferentes escenarios que dan cuenta de la relacion espacial entre la ZCSA y los dos niveles estructurales yuxtapuestos: (1) La ZCSA es coetanea a la exhumacion diferencial del bloque oeste, en cuyo caso las lineaciones minerales buzantes al norte se habrian formado durante este evento, lo que implicaria un movimiento sinistral inverso, consistente con la cinematica de la ZCSA. (2) La ZCSA no es coetanea a la exhumacion, en este caso la zona de cizalle habria generado lineaciones minerales horizontales formadas durante un evento transcurrente sinistral y la exhumacion habria ocurrido con posterioridad, debido a un basculamiento tectonico cuyo pivote estaria al norte de la zona de estudio. | es-ES |
| dc.format | application/pdf | |
| dc.format | text/html | |
| dc.language | eng | |
| dc.publisher | Servicio Nacional de Geología y Minería | en-US |
| dc.relation | http://www.andeangeology.cl/index.php/revista1/article/view/V30n1-a03/545 | |
| dc.relation | http://www.andeangeology.cl/index.php/revista1/article/view/V30n1-a03/html | |
| dc.source | Andean Geology; Vol 30, No 1 (2003); 39-52 | es-ES |
| dc.source | Andean Geology; Vol 30, No 1 (2003); 39-52 | en-US |
| dc.source | 0718-7106 | |
| dc.source | 0718-7092 | |
| dc.title | Geometry and kinematics of Seno Arcabuz Shear Zone, Patagonian Andes, Chile. | en-US |
| dc.title | Geometria y cinematica de la Zona de Cizalle Seno Arcabuz, Andes patagonicos, Chile. | es-ES |
| dc.type | info:eu-repo/semantics/article | |
| dc.type | info:eu-repo/semantics/publishedVersion | |
| dc.type | es-ES | |
| dc.type | en-US |
This item appears in the following Collection(s)
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Andean Geology
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