12/23/2023 0 Comments Alteracoin de la corteza motrixGeology has no boundaries so we may publish papers on any area of knowledge that is interesting to our readers. The Boletín de la Sociedad Geológica Mexicana is a completely free-access electronic journal published semi-annually that publishes papers and technical notes with its main objective to contribute to an understanding of the geology of Mexico, of its neighbor areas, and of geologically similar areas anywhere on Earth’s crust. and related rocks initially deposited in an arc-related basin that was subsequently deformed during the Pampean orogeny. Geochemical signatures and structures of the studied samples are consistent with protolithic sediments of the Puncoviscana Fm. The geometry and sequence of structures and microstructures preserved in all samples are pervasive and suggest a common and uniform deformational history during the Pampean orogeny. Geochemical signatures of low-grade metapsammitic samples (high Hf and Zr content, and high Zr/Sc ratios) indicate crustal recycling. Th/Sc, Zr/Hf, La/Th, La/Sc) imply that the tectonic setting of the source area was a continental island arc and/or an active continental margin. Th-La-Sc, Sc-Th-Zr/10), multi-element patterns, REE characteristics, and diagnostic trace element ratios (i.e. Tectonic discrimination diagrams based on immobile trace elements (e.g. REE element distributions, Eu/Eu* values, and high Zr/Sc and Th/Sc ratios indicate that the samples were likely derived from predominantly upper-crust felsic sources. and related rocks are characterized by moderate Chemical Index of Alteration (CIA) values. Geochemical analyses indicate that the Puncoviscana Fm. The studied rocks are metapelites and metapsammites that were mainly affected by the lower Cambrian Pampean orogeny. AbstractMajor, trace, and rare-earth element data for the Neoproterozoic to early Cambrian Puncoviscana Formation and related higher-grade metasedimentary rocks in Eastern Sierras Pampeanas, NW Argentina, were analyzed to evaluate their provenance, weathering, and tectonic setting during the upper Neoproterozoic-lower Paleozoic.
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