Geochemistry and geochronology of the Sierra de Gomez Limestone-hosted U deposit, Chihuahua: Implications for distribution of Rio Grande rift mineral deposits in northern Mexico
| Autor: | Janet Villarreal-Fuentes, Gilles Levresse, Paul Alexandre, Ángel F. Nieto-Samaniego, Rodolfo Corona-Esquivel |
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| Rok vydání: | 2016 |
| Předmět: |
Calcite
Rift 010504 meteorology & atmospheric sciences Geochemistry Geology 010502 geochemistry & geophysics 01 natural sciences Graben Uranium ore chemistry.chemical_compound chemistry Geochemistry and Petrology Geochronology Meteoric water Economic Geology Fluid inclusions 0105 earth and related environmental sciences Uranophane |
| Zdroj: | Ore Geology Reviews. 76:19-34 |
| ISSN: | 0169-1368 |
| Popis: | Uranium deposits form in a variety of settings. They are partially controlled by the secular evolution of Earth processes, including deposits in extension-related settings such as the intra-cratonic Rio Grande rift. Plio-Quaternary volcanism, mineral deposits, and hydrothermal spots occur along the Chihuahua Central Graben. The age of the Sierra de Gomez U-deposit is 1.8 Ma (based on LA-MC-ICP-MS dating on a uranophane monocrystal), which is contemporaneous with the late mineralization event of the Pena Blanca U-deposit, as well as Rio Grande Rift (RGR)-type deposits in Chihuahua and intraplate volcanism. Studies of fluid inclusions in fluorite and late calcite indicate the presence of hydrocarbons and CH4-rich brine. Homogenization temperatures range from 87 to 112 °C, and the mean composition (2.0 mol NaCl and 0.3 mol CaCl with CH4) is comparable to mineralizing brines in MVT deposits and carbonated hydrocarbon reservoirs. Evolution of C and O stable isotopic values for the calcite cement in the Sierra de Gomez Limestone-hosted U deposit illustrates that two separate calcite precipitation events occurred: (1) travertine filling karst structures in the presence of meteoric water and (2) U mineralization during deep hydrothermal fluid circulation that included interactions with a heat source and basement leaching. In a regional context, a metallogenic model suggests that the Chihuahua Trough area is deep enough to generate fluid migration by hydrothermal and/or compaction processes through RGR extensional faults until a favorable trapping horizon is reached. This causes uranium precipitation because water/rock interaction processes generate a local redox barrier. |
| Databáze: | OpenAIRE |
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