T255 Regional Characterization of Critical Mineral Potential

Wednesday, 18 October 2023
1:30 PM - 5:30 PM
324

GEOLOGY, GEOCHEMISTRY, AND GEOCHRONOLOGY OF THE REE-ENRICHED CAVE PEAK PORPHYRY MO-DEPOSIT, TRANS-PECOS TEXAS

Paper number: T255-13
Program: Technical Sessions
Time: 4:20 PM – 4:35 PM

Authors

Abstract

The Cave Peak deposit is a rift-related, breccia-hosted, fluorine-rich molybdenum porphyry system that is enriched in Nb, REE, and other critical minerals. Cave Peak is the easternmost member of a northwest-trending group of Paleogene intrusions in the Diablo Plateau along with the Marble Canyon stock, an unmineralized, petrogenetically related, compositionally zoned mafic to intermediate pluton. The Cave Peak intrusion shows within-plate geochemical affinity and is the product of a highly differentiated magma series. Curvilinear trends in Harker variation and trace element diagrams record magma differentiation from mafic to intermediate (44-71 wt % SiO2) to felsic (70-76 wt% SiO2) compositions at Marble Canyon and Cave Peak, respectively. Quartz syenite and monzonite from the Marble Canyon stock yielded zircon U-Pb ages of 36.2 ± 0.15 Ma and 36.1 ± 0.09 Ma, respectively. The youngest major intrusion at Cave Peak, an alkali feldspar granite porphyry, has a zircon U-Pb age of 34.8 ± 0.4 Ma, supporting that the Marble Canyon-Cave Peak intrusions represent a magma differentiation trend. Average REE+Y concentrations from the whole-rock geochemical data are 437 ppm (n=9) and 758 ppm (n=10) for Marble Canyon and Cave Peak, respectively. An alkali feldspar granite porphyry of Cave Peak yielded the highest REE+Y concentration of 953 ppm. The Trans-Pecos Magmatic Province is known to host REE-enriched deposits and the elevated REE+Y concentrations recorded for both Cave Peak and Marble Canyon suggest potential for additional critical mineral resources in this region.

Keywords Cave Peak, Porphyry Mo, Geochemistry, U-Pb Geochronology, Critical Minerals

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-390431

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