are earth elements (REE) are becoming increasingly important in modern society due to their numerous uses in manufacturing of components for green and high-tech energy industries. Studying the mechanisms of REE mineral formation in geologic systems is vital for understanding where and how these mineral deposits form. Previous studies of REE mineral deposits have shown that hydrothermal fluids can play a key role in the mobilization and enrichment of REE (Williams-Jones et al., 2000; Gysi et al., 2016; Vasyukova and Williams-Jones, 2018). Fluorite is ideal to study the behavior of REE because of their compatibility in its structure and it is a ubiquitous hydrothermal vein mineral found together with REE fluorocarbonates (i.e., bastnäsite and parisite). However, the controls on hydrothermal fluid-mineral REE partitioning in these deposits are not yet fully understood. In this study, we present petrographic observations of fluorite veins and fluid inclusions from the Gallinas Mountains REE-bearing fluorite veins/breccia deposit in New Mexico (McLemore, 2010; Williams-Jones et al. 2000). The Gallinas Mountains deposit notably contains hydrothermal fluorite and bastnäsite, and is associated with ~30 Ma alkaline igneous rocks intruded into Permian sedimentary rocks (McLemore, 2010). The goal of this study is to better understand the cause of REE variations in fluorite as a function of temperature and salinity of the fluids, and to determine how the REE concentrations change in barren and mineralized veins. Optical microscopy and cold-cathode cathodoluminescence (CL) is used to distinguish different fluorite generations and fluid inclusion types. Scanning electron microscopy (SEM) is used to identify REE minerals, zonation in fluorite, and acquire elemental compositions of different vein minerals. 
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                            Apatite Rare Earth Elements Chemistry and Fluid Inclusion Study in Hydrothermal Veins of the Lemitar Mountains Carbonatite, New Mexico
                        
                    
    
            The Lemitar Mountains carbonatite (Fig. 1A) is a 515 Ma rare earth element (REE) mineral deposit in New Mexico comprising over one hundred carbonatite dikes intruded into Proterozoic igneous rocks [1, 2]. The carbonatite displays grades of up to 1.1 % total REE and showcases variable degrees of hydrothermal autometasomatism and overprinting of the surrounding host rocks through fenitization and veining [1-3]. In this study, we employ a combination of petrography, optical cold-cathode cathodoluminescence and scanning electron microscopy to delineate the mineral paragenesis of the carbonatites and the associated crosscutting hydrothermal veins (Fig. 1). The determination of trace element concentrations in apatite was achieved using LA-ICP-MS. Fluid inclusions were studied in thick sections using optical microscopy, microthermometry and a confocal Raman spectroscopy to assess their salinity, homogenization temperature, and chemical composition. 
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                            - Award ID(s):
- 2039674
- PAR ID:
- 10517887
- Publisher / Repository:
- New Mexico Geological Society
- Date Published:
- ISSN:
- 2834-5800
- Page Range / eLocation ID:
- 66-67
- Format(s):
- Medium: X
- Location:
- Macey Center, Socorro, NM
- Sponsoring Org:
- National Science Foundation
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