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Boletín de la Sociedad Geológica Mexicana Volumen 73, núm. 1, A270820, 2021 |
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Estimación gravimétrica del grosor cortical en el Golfo de California
Gravimetric crustal thickness estimation in the Gulf of California
Anaid Fragoso-Irineo1,*, Javier Lazcano1, Roberto S. Molina-Garza2, Alexander Iriondo2,3
1 Posgrado en Ciencias de la Tierra, Centro de Geociencias, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, México.
2 Centro de Geociencias, Universidad Nacional Autónoma de México, Blvd. Juriquilla no. 3001,76230, Querétaro, México.
3 Department of Geosciences, University of Arizona, 1040 E. 4th Street, Tucson, Arizona 85721.
* Autor para correspondencia: (A. Fragoso-Irineo) This email address is being protected from spambots. You need JavaScript enabled to view it.
How to cite this article:
Fragoso-Irineo, A., Lazcano, J., Molina-Garza, R.S., Iriondo, A., 2021, Estimación gravimétrica del grosor cortical en el Golfo de California: Boletín de la Sociedad Geológica Mexicana, 73 (1), A270820. http://dx.doi.org/10.18268/BSGM2021v73n1a270820
ABSTRACT
In this study 3D inversion of satellite gravimetric data with 3DINVER.M program is applied to model the depth of the crust in the Gulf of California rift. This rift dextrally separates Baja California Peninsula from the North American continent since Miocene, period in which the change occurred from a fundamentally extensional tectonic regime to the present transtensional. Incipient oceanization occurs in various southern sectors along the rift axis, while to the north the presence of oceanic crust is controversial. As a consequence, the crust of the Gulf marine basin and that of adjacent terrestrial regions exhibit important differences in density and thickness, both fundamental parameters of the method, and therefore, we opted to model independently each domain. The crustal thickness models were compared with previous punctual estimates based on seismic methods, obtaining that 98% of the confronted points of the marine model and 87% of the terrestrial model are adjusted to a range of ± 6 km difference, with mean differences of 1.5 km and 3.5 km, respectively. In our models, along the Gulf basin axis and from the south to the north evolves from a hyper-thinned crust (~8−12 km), characteristic of oceanic to transitional crust, to a moderately thinned continental crust (~12−18 km). In the surrounding extended area, known as the Gulf Extensional Province, the continental crust usually varies between ~15 and ~28 km, while on this province flanks the crust reaches ~35−40 km in the thickened domains (Sierra Madre Occidental and Colorado Plateau). Based on our estimates of crustal thickness and the regional geology, a new demarcation for the Gulf Extensional Province is proposed.
Keywords: crustal thickness, Moho, gravimetry, 3D inversion, Gulf of California, rift.
