Boletín de la Sociedad Geológica Mexicana Volumen 67, núm. 1, 2015, p. 75-86 http://dx.doi.org/10.18268/BSGM2015v67n1a6

Calpionellid biostratigraphy, U-Pb geochronology and microfacies of the Upper Jurassic-Lower Cretaceous Pimienta Formation (Tamazunchale, San Luis Potosí, central-eastern Mexico)

Rafael López-Martínez^1,*, Ricardo Barragán¹, Daniela Reháková², Michelangelo Martini¹, Samuel Eguiluz de Antuñano³

¹ Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Delegación Coyoacán, C.P. 04510, México D.F., Mexico.
² Comenius University, Faculty of Natural Sciences, Department of Geology and Paleontology, Mlynská dolina G, 842 15 Bratislava, Slovak Republic.
³ Geologist assessor, Bonampak 103, Coyoacán, C. P. 04700, México, D.F., Mexico.

^* This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Detailed sampling of a stratigraphic section corresponding to the La Pimienta Formation in the state of San Luis Potosí allows the determination of the upper Tithonian Crassicollaria Zone (Remanei, Brevis and Colomi Subzones). The presence of Praetintinnopsella andrusovi Borza and chitinoidellids in the CrassicollariaZone, was interpreted as the result of sedimentary reworking as due to fact that these taxa have not been reported in such a high stratigraphic position. Nonetheless additional work is needed in order to establish a clear relationship. The U-Pb date for a bentonite bed that underlies rocks of the Elliptica Subzone is 139.1 ± 2.6 Ma (late Berriasian-early Valanginian). These new data suggest a different age range for the Elliptica Subzone in Mexico as compared with coeval sections in the Mediterranean Tethys.

Keywords: Calpionellids, microfacies, Upper Jurassic-Lower Cretaceous, central-eastern Mexico.

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