Times are displayed in (UTC-05:00) Central Time (US & Canada) Change

166-2 Mineralogy and Critical Mineral Potential of Alkaline Intrusions in the Northern Trans-Pecos Magmatic Province of Texas

Session: Mineralogical Characterization of Economic Resources: From Critical Minerals to Gemstones

Presenting Author:

Mert Ugurhan

Authors:

Ugurhan, Mert¹, Elliott, Brent², Short, Shelby³

(1) The University of Texas at Austin, Bureau of Economic Geology, Austin, TX, USA, (2) The University of Texas at Austin, Bureau of Economic Geology, Austin, Texas, USA, (3) The University of Texas at Austin, Bureau of Economic Geology, Austin, Texas, USA,

Abstract:

The Trans-Pecos magmatic province of Texas hosts numerous Paleocene to Miocene age intrusive and extrusive igneous bodies that formed during transition from subduction-related compression to subsequent regional extension. A series of alkaline intrusions occur along a northwest-southeast trending line in the northern part of the province, encompassing mafic to highly evolved felsic magmatism. Geochemical analyses and petrographic studies were conducted to characterize these intrusions. They are ferroan, peralkaline to metaluminous in composition, and display within-plate geochemical affinity, suggesting that they were emplaced during an incipient stage of regional extension that formed the Rio Grande Rift in central New Mexico.

Intrusions in the Cornudas Mountains, Sierra Tinaja Pinta, and Black Mountains range in composition from phonolite to trachyte and are enriched in incompatible elements, including Ti, Nb, Zr, U, Th, and REEs. Whole-rock analyses of 107 samples indicate REE+Y concentrations ranging from 450 ppm to 920 ppm, with energy-dispersive spectra obtained from the scanning electron microscope confirming the presence of monazite, eudialyte, bastnäsite, parisite and aeschynite in samples from Cornudas Mountains and Black Mountains. Additionally, Marble Canyon, a compositionally zoned mafic to intermediate pluton, and Cave Peak, a breccia-hosted porphyry molybdenum deposit, are located in the Sierra Diablo Mountains. Average REE+Y concentrations from the whole-rock data are 758 ppm (n=10), and 436 ppm (n=9) for Cave Peak and Marble Canyon, respectively. Cave Peak, in particular, is the highly evolved felsic endmember of this magmatic system and is enriched in F, Nb, Cu, Pb, Zn, W, Sn, and REEs, with monazite, xenotime, yttrofluorite, and yttrocerite identified within the intrusion.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8892

Mineralogy and Critical Mineral Potential of Alkaline Intrusions in the Northern Trans-Pecos Magmatic Province of Texas

Description

Session Format: Oral

Presentation Date: 10/21/2025

Presentation Start Time: 08:20 AM

Presentation Room: HBGCC, 217A

Back to Session