The El Horror uranium anomaly in northeastern Sonora, Mexico: Constraints from geochemical and mineralogical approaches
Por:
Grijalva-Rodriguez, T., Valencia-Moreno, M., Calmus, T., Del Rio-Salas, R., Balcazar-Garcia, M.
Publicada:
1 dic 2017
Resumen:
This work reviews the characteristics of the El Horror uranium prospect
in northeastern Sonora, Mexico. It was formerly detected by a
radiometric anomaly after airborne gamma ray exploration carried out in
the 70's by the Mexican government. As a promising site to contain
important uranium resources, the El Horror was re-evaluated by CFE
(Federal Electricity Commission) by in situ gamma ray surveys. The study
also incorporates rock and stream sediment ICP-MS geochemistry, X-ray
diffraction, X-ray fluorescence, Raman spectrometry and Scanning
Electron Microscopy (SEM) to provide a better understanding of the
radiometric anomaly. The results show that, instead of a single anomaly,
it comprises at least five individual anomalies hosted in hydrothermally
altered Laramide (80-40 Ma) andesitic volcanic rocks of the Tarahumara
Formation. Concentrations for elemental uranium and uranium calculated
from gamma ray surveys (i.e., equivalent uranium) are not spatially
coincident within the anomaly, but, at least at some degree, they do so
in specific sites. X-ray diffraction and Raman spectrometry revealed the
presence of rutile/anatase, uvite, bukouvskyte and allanite as the more
likely mineral phases to contain uranium. SEM studies revealed a process
of iron-rich concretion formation, suggesting that uranium was initially
incorporated to the system by adsorption, but was largely removed later
during incorporation of Fe+3 ions. Stream sediment geochemistry reveals
that the highest uranium concentrations are derived from the southern
part of the Sierra La Madera batholith (similar to 63 Ma), and decrease
toward the El Horror anomaly. (C) 2017 Elsevier Ltd. All rights
reserved.
Filiaciones:
Grijalva-Rodriguez, T.:
Univ Nacl Autonoma Mexico, Posgrad Ciencias Tierra, Mexico City, DF, Mexico
Valencia-Moreno, M.:
Univ Nacl Autonoma Mexico, Inst Geol, Estn Reg Noroeste, Mexico City, DF, Mexico
Calmus, T.:
Univ Nacl Autonoma Mexico, Inst Geol, Estn Reg Noroeste, Mexico City, DF, Mexico
Del Rio-Salas, R.:
Univ Nacl Autonoma Mexico, Inst Geol, Estn Reg Noroeste, Mexico City, DF, Mexico
Balcazar-Garcia, M.:
Inst Nacl Invest Nucl, Mexico City, DF, Mexico
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