REE SIGNATURES OF INTRUSIVES ASSOCIATED WITH PORPHYRY COPPER OF SONORA

REE signatures in simples of plutonic rocks from five copper porphyry systems in Sonora, suggest that there is a petrogenetic process linked to the cooling of a major pluton that generates magma columns of phophyry textura, which are emplaced at shallow levels in the crust. This is revealed by an ap...

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Autores principales: Santillana Villa, Cecilia, Valencia-Moreno, Martín, Ochoa-Landín, Lucas, Del Río-Salas, Rafael
Format: Online
Jezik:spa
Izdano: Universida de Sonora 2022
Online dostop:https://epistemus.unison.mx/index.php/epistemus/article/view/188
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Izvleček:REE signatures in simples of plutonic rocks from five copper porphyry systems in Sonora, suggest that there is a petrogenetic process linked to the cooling of a major pluton that generates magma columns of phophyry textura, which are emplaced at shallow levels in the crust. This is revealed by an apparent reversal in the polarity of the europium anomaly in the REE normalized patterns. In general, the patterns display a LREE-enriched slope, with a well-developed negative europium anomaly in the case of the main pluton. The signatures of the intrusives associated with mineralization are very similar, excepting the europium anomaly, which becomes less negative and even positive. According to existing models, this can be explained by considering that there is a significant fractionation of hornblende during the generation of the porphyritic stock, perhaps under more reducing magmatic conditions.