Efecto de las fracturas de enfriamiento en la formación de fallas normales: El ejemplo de Santa María del Río, San Luis Potosí, MéxicoE
Por:
Botero-Santa P.A., Xu S., Nieto-Samaniego A.F., Alaniz-Álvarez S.A.
Publicada:
1 ene 2020
Categoría:
Earth and planetary sciences (miscellaneous)
Resumen:
The reactivation of pre-existing fractures is an important issue in the study of nucleation, union, growth, and evolution of fault systems. Pre-existing zones of weakness, such as cooling fractures, can determine the configuration of important fault systems. In particular, it is important to study the role of cooling fractures in the reactivation of faults for three reasons: first, there are many cooling fractures in volcanic rocks; second, the vertical fractures have a low tendency to slip; and third, there are many strikes and striae in several directions, making it difficult to interpret their mechanical origin. This paper presents an example of a fault system that overprinted on a volcanic field in Santa Maria del Rio, San Luis Potosi, Mexico. We studied the age, geometry, activity, and kinematics of the SLTFS (San Luis-Tepehuanes Fault System) located in Santa Maria del Rio, in central Mexico, as well as the fault mechanisms and interaction with pre-existing structures, like orthogonal and polygonal cooling joints. Three sites were chosen for the measurement of structural data. The results indicate that the major faults have a NW-SE preferential trend and the minor faults show strikes in all azimuths. This faulting caused the tilt of strata. The older units have higher dips (20° to 25°) than the younger ones (~15°). Curved, superimposed slickenlines and striae parallel to the intersection of two fault planes are probably the result of the interaction with pre-existing fractures during reactivation. Based on these results as well as calculations using the ReActiva 2.4 software (Alaniz-Alvarez et al., 2000; Tolson et al., 2001), we propose that faulting began at depth, and propagated through the cooling joints while advancing to the surface in the current SLTFS configuration. © 2020 Instituto de Geolog+?-?a, Universidad Nacional Aut+?-?noma de M+?-?xico.
Filiaciones:
Botero-Santa P.A.:
Posgrado en Ciencias de la Tierra, Universidad Nacional Autónoma de México, Blvd. Juriquilla No. 3001, Querétaro, 76230, Mexico
Xu S.:
Centro de Geociencias, Universidad Nacional Autónoma de México, Blvd. Juriquilla No. 3001, Querétaro, 76230, Mexico
Nieto-Samaniego A.F.:
Centro de Geociencias, Universidad Nacional Autónoma de México, Blvd. Juriquilla No. 3001, Querétaro, 76230, Mexico
Alaniz-Álvarez S.A.:
Centro de Geociencias, Universidad Nacional Autónoma de México, Blvd. Juriquilla No. 3001, Querétaro, 76230, Mexico
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