The buried southern continuation of the Oaxaca-Juarez terrane boundary and Oaxaca Fault, southern Mexico: Magnetotelluric constraints
Por:
Campos-Enriquez J.O., Corbo-Camargo F., Arzate-Flores J., Keppie J.D., Arango-Galván C., Unsworth M., Belmonte-Jiménez S.I.
Publicada:
1 abr 2013
Resumen:
Thirty magnetotelluric soundings were made along two NW-SE profiles to
the north and south of Oaxaca City in southern Mexico. The profiles
crossed the N-S Oaxaca Fault and the Oaxaca-Juarez terrane boundary
defined by the Juarez mylonitic complex. Dimensionality analysis of the
MT data showed that the subsurface resistivity structure is 2D or 3D.
The Oaxaca and correlative Guichicovi terranes consist of ca. 1-1.4 Ga
granulitic continental crust overlain by Phanerozoic sedimentary rocks,
characterized by high and low resistivities, respectively. The Juarez
terrane consists of oceanic Mesozoic metavolcanic and metasedimentary
rocks, characterized by a low to medium resistivity layer, that is
approximately 10 km thick. The Oaxaca Fault is a Cenozoic aged, normal
fault that reactivated the dextral and thrust Juarez mylonitic complex
north of Oaxaca City: its location south of Oaxaca City is uncertain. In
the southern profile, the MT data show a ca. 20-50 km wide,
west-dipping, relatively low resistivity zone material that extends
through the entire crust. This is inferred to be the Juarez terrane
bounded on either side by the ca. 1-1.4 Ga granulites. The Oaxaca Fault
is imaged only by a major electrical resistivity discontinuity (low to
the west, high to the east) along both the western border of the Juarez
mylonitic complex (northern profile) and the San Miguel de la Cal
mountains (southern profile) suggesting continuity. (C) 2013 Elsevier
Ltd. All rights reserved.
Filiaciones:
Campos-Enriquez J.O.:
Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico
Corbo-Camargo F.:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Juriquilla, Queretaro, Mexico
Arzate-Flores J.:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Juriquilla, Queretaro, Mexico
Keppie J.D.:
Univ Nacl Autonoma Mexico, Inst Geol, Mexico City 04510, DF, Mexico
Arango-Galván C.:
Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico
Unsworth M.:
Department of Physics, Alberta University, Alberta, Canada
Belmonte-Jiménez S.I.:
CIIDIR-IPN, Oaxaca, Mexico
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