Fluorite is very abundant in the Peak District of Derbyshire, U.K. where it was mined extensively since Roman times.
Fluorite (locally called fluorspar) is deposited in veins (with lead and zinc) by hydrothermal activity from igneous intrusions as well as fractures and cavities in limestone and dolomite of the same area. I roamed up those hills to complete an undergraduate thesis! Very impressive hydrothermal activity that is still active today with hot spring activity in many places.
Some of the color varieties of the mineral, like Blue John (purple color, the "Blue" comes from a Cornish word), are unique in that area.
These are the common fluorine deposits worldwide with the top scorer underlined
(1)Magmatic deposits
(1)Fluorite deposits related to granitic intrusions with F-Sn-W-(Be) and fluorite skarn W-Sn and Pb-Zn deposits
(2)Fluorite deposits related toU-REE carbonatites and alkaline intrusive rocks
(3)Granite-related Be-Nb-Ta- fluorite deposits
(4)Pegmatite-hosted F-(Sc) deposits
(5)Volcanic-hosted F-U-Mo deposits
(6)Volcanic-hosted topaz
(7)Granite-related topaz deposits (gemstone)
(8)Intragranitic fluorite deposits
(9)Cryolite deposit related to metasomatic A-type granites
(2)Structure-related deposits
(1)F-bearing mega breccia
(2)Epithermal (“hot brine“) fluoritebreccia veins)
(3)Epithermal F-(Ba) deposits (maars)
(4)Unconformity-related (shallow veins) Pb-Zn-Ba fluorite deposits
(5)Thrustbound and replacement topaz deposits (gemstone)
(3)Sedimentary deposits
(1)Stratabound Pb-Zn-Ba fluorite deposits in carbonaterocks (MVT) including replacement deposits („mantos“)
(2)Stratabound fluorite-celestite deposits in carbonate rocks
(3)Residual and karst-related fluorite deposits
(4)Fluorite cavity-fillings and calcretes
(5)Fluorite replacement / calamine deposits
(6)Phosphorites withF apatite
(7)Topaz placers
Dear Gholamreza Fotoohi Rad Please recommend my answer if helpful
Fluorite (calcium fluoride, CaF2) deposits form under specific geological and geochemical conditions. The quality of a fluorite ore deposit is influenced by various factors, including the geological environment, fluid chemistry, temperature, and pressure. While the precise conditions can vary, the following are key considerations for the formation of a high-quality fluorite ore deposit:
1. **Geological Setting:**
- Fluorite deposits are often associated with specific geological environments, such as granite intrusions, hydrothermal veins, or sedimentary rocks. Granite-related deposits are common, where fluorine-rich fluids interact with calcium-rich rocks.
2. **Fluid Source:**
- The source of fluorine-rich fluids is crucial for the formation of fluorite deposits. These fluids may originate from magmatic processes, such as the alteration of granite rocks, or from hydrothermal circulation.
3. **Temperature and Pressure:**
- The formation of fluorite is influenced by temperature and pressure conditions. Typically, fluorite deposits form under hydrothermal conditions at moderate temperatures. The exact range can vary, but it often falls within the low to moderate-temperature regime.
4. **Hydrothermal Processes:**
- Hydrothermal processes involve the circulation of hot fluids through rocks. In the case of fluorite deposits, hydrothermal fluids carrying fluorine interact with calcium-rich host rocks, leading to the precipitation of fluorite crystals.
5. **Presence of Faults and Fractures:**
- Faults and fractures in the Earth's crust provide pathways for hydrothermal fluids to migrate. Fluorite deposits are often found in association with fault zones where fluid flow and mineralization are enhanced.
6. **Proximity to Magmatic Intrusions:**
- Fluorite deposits can be associated with magmatic intrusions, especially granitic rocks. Magmatic fluids released during the cooling and crystallization of granitic magma may contain fluorine and contribute to the formation of fluorite deposits.
7. **Sedimentary Deposition (Mississippi Valley-Type):**
- Some fluorite deposits are formed through sedimentary processes, particularly in Mississippi Valley-Type (MVT) deposits. In these cases, fluorine-rich fluids migrate through sedimentary rocks, leading to the deposition of fluorite.
8. **Geochemical Conditions:**
- Geochemical conditions play a role in fluorite precipitation. The presence of other minerals, such as barite, sulfides, or carbonate minerals, can influence the geochemical environment and impact the quality of fluorite deposits.
9. **Redox Conditions:**
- The redox conditions (oxidation-reduction) in the geological environment can influence the solubility of fluorine and the precipitation of fluorite. Reducing conditions are often favorable for fluorite deposition.
10. **Mineralization Events:**
- Fluorite deposits may form during specific mineralization events related to tectonic or magmatic activity. These events create favorable conditions for the interaction of fluids with host rocks.
Understanding the specific conditions under which fluorite deposits form is essential for exploration and mining activities. Geological surveys, geochemical analyses, and an understanding of the regional geological history are crucial for identifying areas with the potential for high-quality fluorite ore deposits.
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