150-1 Examining the potential of U-Pb and (U-Th)/He of Fluorite Deposits along the Rio Grande Rift, New Mexico

Session: Geochronology of Critical Mineral Deposits with Special Reference to U-Th-Pb Dating of Common-Pb-Rich Minerals (Posters)

Poster Booth No.: 278

Presenting Author:

Brice Banda

Authors:

Banda, Brice¹, Everard, Jenna², Hemming, Sidney Rasbury³, Rasbury, Emma Troy⁴, Cox, Stephen⁵, Holt, William⁶, Rakovan, John⁷, Nelson, Rex⁸

(1) Department of Earth and Environmental Science, Columbia University, New York, NY, USA; Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA, (2) Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA, (3) Department of Earth and Environmental Science, Columbia University, New York, NY, USA; Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA, (4) Department of Geosciences, Stony Brook University, Stony Brook, New York, USA, (5) Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York, USA, (6) Department of Geosciences, Stony Brook University, Stony Brook, New York, USA, (7) New Mexico Bureau of Geology and Mineral Resources, Socorro, New Mexico, USA, (8) Private Mine Claim Owner, Albuquerque, New Mexico, USA,

Abstract:

The orogenic collapse of the North American Cordillera (NAC) in the western US has been studied extensively, yet the history of the major diachronous extension remains imperfectly understood. Such rifting and collapse in the NAC are broadly associated with the formation of major mineralization belts across the region. Thus, constraining the timing and origin of the orogenic collapse is important for understanding the processes that lead to significant ore endowment and the greater geologic history of the region. 

The Rio Grande Rift (RGR) forms the eastern zone of major extension in the western US, and its formation is thought to be related to the progression of orogenic collapse. In New Mexico, extensive fluorspar deposits have been mined along the RGR. Fluorite deposits are considered to be related to the formation of the RGR, so radiometric dates from them would facilitate improved understanding of rifting history in the region and its relationship to the evolving NAC.

Thus we investigate the potential for U-Pb and (U-Th)/He dating of fluorites from mine sites along the RGR to constrain the timing of fluid mobilization of critical minerals and provide insights into the  processes of rifting. Low U/Pb ratios in test samples have prevented U-Pb dating thus far but all studied samples have measurable U and Th. This work is exploring the possibility of applying (U-Th)/He dating to fluorite samples from the Zuni Mountains and Tijeras Canyon sites in New Mexico. Based on LA-ICPMS and synchrotron XRF mapping to evaluate elemental composition, with a focus on U, Th, and Pb concentrations. These data will be used to constrain the precipitating fluids which, if combined with successful (U-Th)/He dating, will provide a better understanding of critical mineral emplacement coinciding with both past and active deformation of the region.

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

doi: 10.1130/abs/2025AM-8013

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