Abstract

This work shows the unpublished occurrence of a preliminary mineralization of Rare Earths, Platinum and Gold, in a sedimentary outcrop of Jurassic Lower Pliensbachian. The location of this deposit was achieved by applying an indirect method of exploration based in the identification and analysis of sedimentary transgressions of heterochronies ages and the identification of a Rift – type mega –structure. According with the used methodology, it was carried out a study of the discordant relationships between two types of sediments: continental and marine, which represent an unpublished methodology used in researches related to mining exploration in Mexico (and could be used in other countries) and thus, was found the deposit which was wholly characterized in this work. The most important results found according the characterization done, show the existence of light rare earths, principally Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Hm, Er, Tm and Yb, in values that show positive anomalies in comparison with the distribution of elements in upper continental crust according to the Clarke, reflecting so a felsic affinity of the mineral deposit. Also, positive anomalies of platinum, and Pd (observed by X-mapping), were determined with marginal contents of Au and Ag (determined by X-Ray mappings); and finally the base metals Zn, Pb and Cu were detected in low contents, which could be due to the presence of altered shale. According to the sedimentary lithology found, which was of siliciclastic type; to the exhalative roots observed during the fieldwork; the presence of quartz minerals such as biotite and muscovite; the presence of minerals of hydrothermal remobilization like chalcopyrite with some base metals of Zn, Cu, Pb, altered shale, as well as sulfur deficiency; this mineral reservoir could be defined as a SEDEX–Type.

Keywords: Rare earths; Platinum; SEDEX ore body; Rift mega structure; transgression