Paleomagnetic study of the Valle de Santiago volcanics, Michoacán-Guanajuato volcanic field, Mexico
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| Natura: | Artículo científico |
| Lingua: | en |
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Universidad Nacional Autónoma de México
1999
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| _version_ | 1876458204491153408 |
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| author | Rosa María Uribe Cifuentes |
| author_facet | Rosa María Uribe Cifuentes |
| contents | Paleomagnetic study of the Valle de Santiago volcanics, Michoacán-Guanajuato volcanic field, Mexico Rosa María Uribe Cifuentes Jaime Urrutia Fucugauchi Ciencias de la Tierra Plio Michoacan Tectonics Quaternary Paleomagnetism The Valle de Santiago area of the Michoacán-Guanajuato volcanic field is characterized by a 7 km by 50 km NNW-SSEtrending cluster of 20 maars, 13 in a smaller sub-area. This volcanic lineament may be associated with a pre-existing fault or zoneof structural weakness, which is approximately normal to the regional structure of the Trans-Mexican volcanic belt (TMVB). Onehundred and twenty one samples were collected from 13 volcanic units of Pliocene andesites and Quaternary andesites andbasalts, including the maars, cinder cones and composite volcanoes. The magnetic polarity except at one site is normal. The oldestK-Ar date associated with maar volcanism is 1.2 Ma. The magnetic polarity suggests that activity took place within the BrunhesChron, implying ages younger than 0.78 Ma. The overall mean direction and paleomagnetic pole location from 10 sites are Dec =353.7°, Inc = 39.2°, k = 42, a95 = 7.6°, and PLAT = 78.4° N and PLONG = 180.0° E. The Valle de Santiago lineament forms partof a larger system in the northern part of the TMVB that includes the Querétaro-Taxco fault zone (QTFZ). These NNW-SSEtrending lineaments intersect the young E-W and ENE-WSW structural trends of the TMVB, represented in the area by theChapala-Tula fault zone. Paleomagnetic studies in the eastern Chapala basin have documented counter-clockwise (CCW) rotations.Studies in the Acambay graben close to the intersection with the QTFZ yield variable amounts of clockwise (CW) and CCWrotations. The mean declination lies to the west -6.3° + 6.1° of the expected direction, within the statistical uncertainty. Results forthe Valle de Santiago area suggest a possible small CCW rotation associated with the regional compressional stress field acting onthe NNW-SSE Valle de Santiago lineament and the E-W Chapala-Tula fault system. 1999 artículo científico 0016-7169 https://www.redalyc.org/articulo.oa?id=56838402 en http://www.redalyc.org/revista.oa?id=568 Geofísica Internacional application/pdf Universidad Nacional Autónoma de México Geofísica Internacional (México) Num.4 Vol.38 |
| format | Artículo científico |
| id | redalyc_56838402 |
| institution | Redalyc |
| language | en |
| publishDate | 1999 |
| publisher | Universidad Nacional Autónoma de México |
| spellingShingle | Paleomagnetic study of the Valle de Santiago volcanics, Michoacán-Guanajuato volcanic field, Mexico Rosa María Uribe Cifuentes Ciencias de la Tierra Plio Michoacan Tectonics Quaternary Paleomagnetism Paleomagnetic study of the Valle de Santiago volcanics, Michoacán-Guanajuato volcanic field, Mexico Rosa María Uribe Cifuentes Jaime Urrutia Fucugauchi Ciencias de la Tierra Plio Michoacan Tectonics Quaternary Paleomagnetism The Valle de Santiago area of the Michoacán-Guanajuato volcanic field is characterized by a 7 km by 50 km NNW-SSEtrending cluster of 20 maars, 13 in a smaller sub-area. This volcanic lineament may be associated with a pre-existing fault or zoneof structural weakness, which is approximately normal to the regional structure of the Trans-Mexican volcanic belt (TMVB). Onehundred and twenty one samples were collected from 13 volcanic units of Pliocene andesites and Quaternary andesites andbasalts, including the maars, cinder cones and composite volcanoes. The magnetic polarity except at one site is normal. The oldestK-Ar date associated with maar volcanism is 1.2 Ma. The magnetic polarity suggests that activity took place within the BrunhesChron, implying ages younger than 0.78 Ma. The overall mean direction and paleomagnetic pole location from 10 sites are Dec =353.7°, Inc = 39.2°, k = 42, a95 = 7.6°, and PLAT = 78.4° N and PLONG = 180.0° E. The Valle de Santiago lineament forms partof a larger system in the northern part of the TMVB that includes the Querétaro-Taxco fault zone (QTFZ). These NNW-SSEtrending lineaments intersect the young E-W and ENE-WSW structural trends of the TMVB, represented in the area by theChapala-Tula fault zone. Paleomagnetic studies in the eastern Chapala basin have documented counter-clockwise (CCW) rotations.Studies in the Acambay graben close to the intersection with the QTFZ yield variable amounts of clockwise (CW) and CCWrotations. The mean declination lies to the west -6.3° + 6.1° of the expected direction, within the statistical uncertainty. Results forthe Valle de Santiago area suggest a possible small CCW rotation associated with the regional compressional stress field acting onthe NNW-SSE Valle de Santiago lineament and the E-W Chapala-Tula fault system. 1999 artículo científico 0016-7169 https://www.redalyc.org/articulo.oa?id=56838402 en http://www.redalyc.org/revista.oa?id=568 Geofísica Internacional application/pdf Universidad Nacional Autónoma de México Geofísica Internacional (México) Num.4 Vol.38 |
| title | Paleomagnetic study of the Valle de Santiago volcanics, Michoacán-Guanajuato volcanic field, Mexico |
| topic | Ciencias de la Tierra Plio Michoacan Tectonics Quaternary Paleomagnetism |
| url | https://www.redalyc.org/articulo.oa?id=56838402 |