Fluorine, fluorite, and fluorspar in central Colorado

Wallace, Alan R.

doi:10.3133/sir20105113

Cited by 6 publications

(14 citation statements)

References 43 publications

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“…manufacture of mullite), as steelmaking flux, in the production of F-bearing compounds (such as sodium fluoride, which is used in toothpaste), the manufacture of ceramics and glasses, and has some value as a gemstone (Winward, 1976). Fluorspar, the generic term for any F-rich ore (Wallace, 2010), is used industrially as a flux for smelting and in the production of certain glasses and enamels (Miller, 2011). The purest grades of fluorspar are used as a source of fluoride for hydrofluoric acid production, and in the manufacture of uranium and optics (Miller, 2011).…”

Section: Topaz and Its Status As An Ore Mineralmentioning

confidence: 99%

“…Other possible sources of F for these industrial and economic processes comprise cryolite (Na3AlF6), fluoroapatite [Ca5F(PO4)3], sellaite (MgF2), and villiamite (NaF), although these alternatives are much rarer. Nonetheless, while fluorite (CaF) is more commonly mined as fluorspar (Wallace, 2010), given its much higher weight-percentage of F (~48.7 wt. %) compared to topaz (~11.5 wt.…”

Section: Topaz and Its Status As An Ore Mineralmentioning

confidence: 99%

“…These TSRQ gneisses and adjacent country rocks form the focus of this research. Figure 1.1 Regional-scale map showing known major occurrences of topaz within the Colorado Front Range (Wallace, 2010). Evergreen is located within the red box shown to the west of Denver.…”

Section: Project Aims and Motivationmentioning

confidence: 99%

“…Topaz (Al2SiO4(F,OH)2) is an Al-and F-bearing nesosilicate mineral that occurs mainly as (1) a primary crystallization product in intrusive felsic igneous rocks, such as granite or pegmatite, (2) as a product of hydrothermal alteration in the crust, commonly within quartz veins and greisens, or (3) concentrated in secondary alluvial placer deposits that form via erosion of topaz-rich host rocks (Lishmund, 1974). Its physical and chemical resistance to near-surface weathering and relatively high density (3.55 g/cm 3 ) can also lead to it accumulating in place when its parent rock erodes or disaggregates (Wallace, 2010). In Central Colorado, U.S.A., topaz is nearly always associated with Proterozoic igneous rocks, such as those in the Pikes Peak region, with lesser amounts within or adjacent to Tertiary plutons and volcanic formations ( Front Range exhibit gem-quality examples that are widely sought after by mineral collectors (Wallace, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Its physical and chemical resistance to near-surface weathering and relatively high density (3.55 g/cm 3 ) can also lead to it accumulating in place when its parent rock erodes or disaggregates (Wallace, 2010). In Central Colorado, U.S.A., topaz is nearly always associated with Proterozoic igneous rocks, such as those in the Pikes Peak region, with lesser amounts within or adjacent to Tertiary plutons and volcanic formations ( Front Range exhibit gem-quality examples that are widely sought after by mineral collectors (Wallace, 2010).…”

Section: Introductionmentioning

confidence: 99%

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Formation of Topaz-Enriched Gneiss in the East-Central Colorado Front Range via Crystallization of Mesoproterozoic Halogen-Rich Granitic Magmas

Cayes¹

2019

Geological Society of America Abstracts With Programs

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Metamorphic rocks enriched in economically valuable minerals occur in all mountain belts worldwide, yet their processes of formation are often incompletely understood. Topaz [Al2SiO4(F,OH)2] is a naturally occurring nesosilicate of great economic and industrial value, and is most commonly found in silica-rich igneous rocks. However, conspicuous 70-ft-thick bands of topaz-, sillimanite-, rutile-, and quartz-rich (TSRQ) metamorphic gneiss occur in the Evergreen region of the east-central Front Range, Colorado, immediately adjacent to "normal" amphibolite and pelitic schist horizons. Bulk-rock geochemistry and isocon analysis shows that all mobile elements (e.g. Na, K, Mg, Ca) have been leached from these TSRQ rocks when compared to adjacent F-poor lithologies, indicating that the TSRQ gneiss must have interacted at some point with halogen-rich fluids. In addition, thermobarometry conducted via conventional and phase diagram-based techniques suggests pressure-temperature conditions of equilibration of ~720 °C and ~6.0 kbar, defining isotherms consistent with metamorphism in the middle continental crust during active mountain building. In-situ U-Pb dating of monazite within TSRQ units produced concordant ages mostly between c. 1.70 Ga, recording burial and prograde metamorphism associated with the Yapavai and/or Matatzal orogeny, and c. 1.65 Ga representing the timing of later F-rich fluid metasomatism. Together, these data are interpreted as recording metasomatic alteration in the middle crust by F-rich fluids released due to crystallization of nearby plutons, such as the Boulder Creek granodiorite at c. 1.71 Ga. As such, these topaz-rich horizons are interpreted to represent in-situ transformation of an older metamorphic assemblage, and not the metamorphosed products of weathered, pre-orogenic high-F tuffs or lava flows that were subsequently buried, as suggested by some previous studies. These results have far-reaching implications for constraining the behavior of halogens in the geological environment and for defining best-practices for future exploration of F-rich metamorphic rocks and ore deposits.

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Section: Topaz and Its Status As An Ore Mineralmentioning

confidence: 99%

Section: Topaz and Its Status As An Ore Mineralmentioning

confidence: 99%

Section: Project Aims and Motivationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Formation of Topaz-Enriched Gneiss in the East-Central Colorado Front Range via Crystallization of Mesoproterozoic Halogen-Rich Granitic Magmas

Cayes¹

2019

Geological Society of America Abstracts With Programs

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Arsenic and fluorine in groundwater in northern Mexico: spatial distribution and enrichment factors

Gutiérrez

Herrera²,

Gaytán-Alarcón³

2022

Environ Monit Assess

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North-central Mexico has groundwater contaminated with arsenic (As) and uoride (F). Based on the dispersion patterns of these solutes, their sources are linked to felsic volcanic rock fragments and secondary minerals (clays, iron oxyhydroxides) within the alluvium ll of the aquifers. However, little is known about the effect of the enrichment factors for F and As in this area. Natural enrichment factors include evaporation, Ca/Na, and competitive adsorption and desorption from solid phases. This study used 1,237 groundwater quality data measurements from 305 sampling sites collected between 2012 and 2019 in the state of Durango in north-central Mexico. To determine the contribution of enrichment factors to As and F content, the study area was divided into four sections, two being in the mountainous part of the state and two in the high plateaus. The data were compared among sections and analyzed using Spearman correlation and Piper and Block diagrams. The results indicate that the main solute enrichment mechanism are evaporation and weathering of silicates and evaporites. Among the four sections, As, pH, and HCO 3 seemed not to vary, F varied slightly, and nitrate and total dissolved solids varied the most. The lack of variation in As among sections is associated to its strong adsorption to clay minerals and iron oxyhydroxides, whereas the diminished F content in the eastern sections is likely linked to the adsorption of F to precipitating calcite (, since groundwater is saturated with respect to calcite ( SI calcite = 0.43) and undersaturated for uorite (SI uorite = -1.16). These processes shed light on the distribution of F and As in this area, and are likely operating in other states in northern Mexico and in semi-arid areas elsewhere.

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Origin and age of rift related fluorite and manganese deposits from the San Rafael Massif, Argentina

Rubinstein

Zappettini

2015

Ore Geology Reviews

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Fluorine, fluorite, and fluorspar in central Colorado

Cited by 6 publications

References 43 publications

Formation of Topaz-Enriched Gneiss in the East-Central Colorado Front Range via Crystallization of Mesoproterozoic Halogen-Rich Granitic Magmas

Formation of Topaz-Enriched Gneiss in the East-Central Colorado Front Range via Crystallization of Mesoproterozoic Halogen-Rich Granitic Magmas

Arsenic and fluorine in groundwater in northern Mexico: spatial distribution and enrichment factors

Origin and age of rift related fluorite and manganese deposits from the San Rafael Massif, Argentina

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