ARTÍCULO

Geochemistry and detrital zircón geochronology of metasedimentary rocks in the Sierra Madre terrane, Mexico: Implications of deposition along the western margin of Pangea.

Torres-Sánchez, S.A., Augustsson C., Jenchen, U., Barboza-Gudiño, J. R., Gärtner, A., Hoffman, M., Linneman, U.,
GeologicalJournal 2021, 1-36. https://doi.org/10.1002/gi.4108, 2024.

ABSTRACT:

The basement complex of the Sierra Madre region in northeastern Mexico is classified into four domains: a) granulite facies rocks of Grenville age (ca. 1 Ga) known as the Novillo Gneiss, b) the Paleozoic Granjeno Schist, c) an unmetamorphosed succession of Paleozoic marine siliciclastic and volcanic rocks, and d) an Ordovician plagiogranite body. We present a geochemical and provenance study of the metasedimentary rocks of the Granjeno Schist, which are associated with metavolcanic and meta-ultramafic rocks. In the Granjeno Schist, trace element ratios (Th/Sc, La/Sch, La/Sc, Zr/Sc) and REE compositions of the metasedimentary rocks are similar to values in mean continental crust values and are consistent with derivation of detritus from felsic rocks. Chemical index of alteration values of 30-80 indicate low to moderate weathering of the source. The clastic metasedimentary rocks have moderately radiogenic Nd-isotopic compositions with initial ?Nd(t) values from -9 to -6, and model ages between 1.5 and 1.7 Ga. Ages of detrital zircon grains from the metasedimentary rocks are mostly 1.6-1.1 Ga, but some ages are 530 Ma to 410 Ma.