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| Format: | Artículo científico |
| Language: | en |
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Universidad Nacional Autónoma de México
2002
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| Online Access: | https://www.redalyc.org/articulo.oa?id=56841206 |
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Table of Contents:
- Volcanic stratigraphy and geological evolution of the Apan region, east-central sector of the Trans-Mexican Volcanic Belt J. C. Mora A. García Palomo Gustavo Tolson G. Valdez J. L. Macías Ciencias de la Tierra Apan Geology stratigraphy Central Mexico structural geology The Apan region, which straddles the central and eastern sectors of the Trans-Mexican Volcanic Belt (TMVB), wasgeologically shaped by interrelated, intermittent tectonism and volcanism. The oldest volcanic rocks in the area were eruptedabout 13.5 Ma ago, followed by a nearly 10-million year volcanic hiatus. Volcanism in the area then resumed ~3.0-1.5 Ma; themost recent volcanic activity occurred in the late Pleistocene (~42-31 ka). The volcanic rocks in the Apan region range incomposition from basalt to rhyolite (50-75 wt.% SiO2) and exhibit calc-alkaline affinity; their geochemical characteristics suggestthat they are subduction-zone eruptive products. Detailed geologic and stratigraphic studies using a new digital 1:100 000 scalebase map for compilation of new and previous data, coupled with new K-Ar age determinations, demonstrate that the loci ofvolcanic centers in the region were controlled largely by a system of NE-SW-trending normal faults and associated horst-andgrabenstructures, resulting from a stress field with a least principal stress (σ3) oriented to the NW. Moreover, the results of thisstudy, combined with a reexamination of geologic and age data from other investigations of the TMVB, make possible a refinedcorrelation of the volcanic stratigraphy of the Apan region with the stratigraphic sequences of volcanic rocks in other areas of theTMVB. An important conclusion of our study is that volcanic activity in the TMVB was initiated during the Middle Miocene. 2002 artículo científico 0016-7169 https://www.redalyc.org/articulo.oa?id=56841206 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