Formation of fluorite in sedimentary basins

Fluid inclusion and microfabric studies on Zechstein carbonates (Ca2) and related fracture mineralizations – New insights on gas migration in the Lower Saxony Basin (Germany)

“…As described by Möller et al (1980) Microfabric details from a fluorite nodule (Figure 6a) revealed that this flame structure was in part previously filled with anhydrite, which was subsequently replaced by Fluorite A. Therefore, we assume that Fluorite A had a sedimentary predecessor and was mobilized during burial.…”

“…Numerous studies on fluorite have shown (Bau and Dulski, 1995;Möller, 1991, 1992;Jacob, 1974;Lüders, 1991;Möller et al, 1976;Möller et al, 1980;Schulz, 1980;Schwinn and Markl, 2005) how distributions of REE and Y in fluorite may help identifying the environment of crystallization, i.e. distinguish between primary crystallized and recrystallized fluorite (Möller et al, 1976).…”

REY and Trace Element Chemistry of Fluorite from Post-Variscan Hydrothermal Veins in Paleozoic Units of the North German Basin

“…A syn-sedimentary formation of fluorite in the NGB has been ascribed by Möller et al [25]. They also discussed the processes leading to the necessary enrichment of fluorine from marine waters to form fluorite.…”

“…Seawater and marine pore waters are usually under saturated in F-and thus precipitation of fluorite is prevented in oxygenated seawater. Under these conditions the diagenetic formation of fluorite is linked to dolomite formation in calcareous sediments due to Mg 2+ removal from pore fluids and consequent release of F − due to break-up of MgF + complexes [25]. Organic material e.g., [77,78], fresh water influx with elevated fluorine concentrations attributed to pegmatitic sources [79], or a volcanogenic source [80,81] have also been invoked to account for the required saturation to allow fluorite precipitation under diagenetic conditions.…”

Overturned geopetal structures formed by solution of sulfates, Triassic (Rhaetian) Portoro limestone, Portovenere area (la Spezia), Liguria, Italy

“…We have also found several pseudomorph clusters withinthemoreshalylimestonebeds stratigraphically below (nowstructurally above)thequarryable Portoro, and these pseudomorphs are concentrated 40 A few crystal pseudomorphs contain a small central anhedralmassof clear fluorite. Fluoriteis anoccasional accessorymineralin tidal-flatdolomites(Mooreet~l.1972; Moller et al 1980;Cook et al 1985), and Hein (1981) reportsit on top of sedimentfills withincavitiesin fenestral dolomite. However,fluorine also occurs in evaporite minerals to the extent of 100-900ppm (Koritnig, 1951), and fluorite has also been found in evaporite related sediments (Friedman and Radke, 1979;Rouchy et al 1987).…”