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| Natura: | Artículo científico |
| Lingua: | en |
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Universidad Nacional Autónoma de México
2002
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| Accesso online: | https://www.redalyc.org/articulo.oa?id=56841203 |
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Sommario:
- Geometry of the El Fresnal basin, northern Chihuahua, Mexico, as inferred from three-dimensional gravity modeling (parte A) A. Valiente Banuet J. A. Rodríguez J. Ortega Ramírez W. L. Bandy J. M. Maillol Ciencias de la Tierra Mexico Chihuahua Río Grande rift Gravity anomalies sedimentary basins A multidisciplinary study of the El Fresnal basin, Chihuahua, Mexico is being conducted to investigate the relationshipsbetween the structure, vegetation and geomorphology and the Quaternary paleoenvironment. As part of this study, 221 newgravity measurements were collected within the basin and combined with 506 preexisting measurements from the surroundingarea to determine the basin geometry and the depth of the sediment infill. A basement-depth model calculated from these dataindicates that the El Fresnal basin consists of two sub-basins separated by a basement high, which is presently buried by about 500meters of sediments. The southern sub-basin, which lacks an axial playa lake, extends for 20 km in a N21ºW direction andcontains 800 meters of sediments. The geometry of the sub-basin is suggestive of a half-graben with the major normal fault locatedto the west. The northern sub-basin, within which lies the playa lake Laguna El Fresnal, extends for 20 km in a N10ºE directionand contains 1500 meters of sediments. Like the southern sub-basin, its geometry is suggestive of a half-graben; however, unlikethe southern sub-basin, the major normal fault is located to the east. In conjunction with previous studies of other rift basinscomprising the Río Grande rift, the orientations of the two sub-basins suggest that the southern sub-basin formed first, during thelate Oligocene to early Miocene, followed by the formation of the northern sub-basin sometime after the early Miocene when theorientation of the tensional stresses within the rift changed from WNW-ESE to E-W. Since the playa lake is now confined to thenorthern sub-basin, it appears that subsidence is presently occurring only in the northern sub-basin. 2002 artículo científico 0016-7169 https://www.redalyc.org/articulo.oa?id=56841203 en http://www.redalyc.org/revista.oa?id=568 Geofísica Internacional application/pdf Universidad Nacional Autónoma de México Geofísica Internacional (México) Num.2 Vol.41