The Aztlán Fault System: control on the emplacement of the Chichinautzin Range volcanism, southern Mexico Basin, Mexico. Seismic and gravity characterization

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Autor principal: José Oscar Campos-Enríquez
Formato: Artículo científico
Lenguaje:en
Publicado: Sociedad Geológica Mexicana, A.C. 2015
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author José Oscar Campos-Enríquez
author_facet José Oscar Campos-Enríquez
contents The Aztlán Fault System: control on the emplacement of the Chichinautzin Range volcanism, southern Mexico Basin, Mexico. Seismic and gravity characterization José Oscar Campos-Enríquez Javier Francisco Lermo-Samaniego Yanet Teresa Antayhua-Vera Marcos Chavacán Victor-Manuel Ramón-Márquez Ciencias de la Tierra seismicity Mexico Basin Chichinautzin Range Aztlán Fault System shallow crustal model Gravity and seismic studies enabled us to establish the major features of the shallow crustal structure beneath Chichinautzin Range. Accordingly, the Chichinautzin Range evolved above Mesozoic calcareous rocks lying on a metamorphic basement. To the north and south this basement is downfaulted. Nevertheless the north dipping faults downward displace the basement to larger depths (2 to 3 km) in the Mexico and Toluca basins. In the Morelos Basin, the basin is shallower. As block-faulting evolved, the basement edge migrated southwards, thus widening an E-W oriented major depression south of the Mexico Basin. In particular, gravity modeling enabled us to integrate the different faults mapped up to today in and around the Chichinautzin Range into a fault system that can be correlated from the Nevado de Toluca. This system will be referred to collectively as the Aztlán Fault System. The Xicomulco, Aztec (central and major fault) and La Pera faults are featured by seismicity. Orientation and dips obtained from simple and composite mechanisms indicate NW-SE to N-S extension with minor E-W left-lateral movement. In particular, seismicity extends down to the brittle-ductile transition crustal zone (maximum hypocentral depths of about 15 km) but consequently the major faults, considering their length, should reach lower crustal levels (approximately 40 km). This system is a major active fault system of at least 100 km in length and 30 – 40 km in width, with a density of approximately 10 E-W faults in 30 km, and local extension of about 10 %. In conjunction with pre-existing NW-SE and NE-SW faults, this E-W fault system would have intensely fractured the crust beneath the Sierra de Chichinautzin. This high degree of fracturing would have enabled the relatively fast emplacement of large quantities of volcanic material to give rise to the Chichinautzin Range, closing the Mexico Basin to the south. The gravity model shows how the different styles of structures north and south of the Chichinautzin Range (extensional and compressive) accommodate themselves. In particular, faults of the Taxco-San Miguel de Allende system affect the basement of the Morelos Basin well further south. 2015 artículo científico 1405-3322 https://www.redalyc.org/articulo.oa?id=94340680013 en http://www.redalyc.org/revista.oa?id=943 Boletín de la Sociedad Geológica Mexicana application/pdf Sociedad Geológica Mexicana, A.C. Boletín de la Sociedad Geológica Mexicana (México) Num.2 Vol.67
format Artículo científico
id redalyc_94340680013
institution Redalyc
language en
publishDate 2015
publisher Sociedad Geológica Mexicana, A.C.
spellingShingle The Aztlán Fault System: control on the emplacement of the Chichinautzin Range volcanism, southern Mexico Basin, Mexico. Seismic and gravity characterization
José Oscar Campos-Enríquez
Ciencias de la Tierra
seismicity
Mexico Basin
Chichinautzin Range
Aztlán Fault System
shallow crustal model
The Aztlán Fault System: control on the emplacement of the Chichinautzin Range volcanism, southern Mexico Basin, Mexico. Seismic and gravity characterization José Oscar Campos-Enríquez Javier Francisco Lermo-Samaniego Yanet Teresa Antayhua-Vera Marcos Chavacán Victor-Manuel Ramón-Márquez Ciencias de la Tierra seismicity Mexico Basin Chichinautzin Range Aztlán Fault System shallow crustal model Gravity and seismic studies enabled us to establish the major features of the shallow crustal structure beneath Chichinautzin Range. Accordingly, the Chichinautzin Range evolved above Mesozoic calcareous rocks lying on a metamorphic basement. To the north and south this basement is downfaulted. Nevertheless the north dipping faults downward displace the basement to larger depths (2 to 3 km) in the Mexico and Toluca basins. In the Morelos Basin, the basin is shallower. As block-faulting evolved, the basement edge migrated southwards, thus widening an E-W oriented major depression south of the Mexico Basin. In particular, gravity modeling enabled us to integrate the different faults mapped up to today in and around the Chichinautzin Range into a fault system that can be correlated from the Nevado de Toluca. This system will be referred to collectively as the Aztlán Fault System. The Xicomulco, Aztec (central and major fault) and La Pera faults are featured by seismicity. Orientation and dips obtained from simple and composite mechanisms indicate NW-SE to N-S extension with minor E-W left-lateral movement. In particular, seismicity extends down to the brittle-ductile transition crustal zone (maximum hypocentral depths of about 15 km) but consequently the major faults, considering their length, should reach lower crustal levels (approximately 40 km). This system is a major active fault system of at least 100 km in length and 30 – 40 km in width, with a density of approximately 10 E-W faults in 30 km, and local extension of about 10 %. In conjunction with pre-existing NW-SE and NE-SW faults, this E-W fault system would have intensely fractured the crust beneath the Sierra de Chichinautzin. This high degree of fracturing would have enabled the relatively fast emplacement of large quantities of volcanic material to give rise to the Chichinautzin Range, closing the Mexico Basin to the south. The gravity model shows how the different styles of structures north and south of the Chichinautzin Range (extensional and compressive) accommodate themselves. In particular, faults of the Taxco-San Miguel de Allende system affect the basement of the Morelos Basin well further south. 2015 artículo científico 1405-3322 https://www.redalyc.org/articulo.oa?id=94340680013 en http://www.redalyc.org/revista.oa?id=943 Boletín de la Sociedad Geológica Mexicana application/pdf Sociedad Geológica Mexicana, A.C. Boletín de la Sociedad Geológica Mexicana (México) Num.2 Vol.67
title The Aztlán Fault System: control on the emplacement of the Chichinautzin Range volcanism, southern Mexico Basin, Mexico. Seismic and gravity characterization
topic Ciencias de la Tierra
seismicity
Mexico Basin
Chichinautzin Range
Aztlán Fault System
shallow crustal model
url https://www.redalyc.org/articulo.oa?id=94340680013