Genesis of the carbonatite-hosted fluorite deposit at Amba Dongar, India; evidence from fluid inclusions, stability isotopes, and whole rock-mineral geochemistry

Palmer, D.A.; Williams‐Jones, Anthony E.

doi:10.2113/gsecongeo.91.5.934

Cited by 75 publications

(44 citation statements)

References 19 publications

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“…The following points are noted: (1) samples of different coloured fluorite from locality KP-96-2 (2, 2.IB, 2.2C) have similar trace element chemistry, except for Ba and Sr, which are related to microinclusions o f barite. Thus, the colour variation in fluorite cannot be related to any of the trace elements determined in this study; (2) levels of Rb, Sr, Li and Ba are generally low in all samples and compare to levels reported in hydrothermal fluorite from the Lake Ainslie area o f Cape Breton Island (Macdonald 1999), but contrasts with the trace element chemistry of fluorite associated with carbonatite (e.g., Palmer and Williams-Jones 1996). Elevated Ba in sample KP-96-5.1 (10376 ppm) relates to microinclusions o f barite in the separate, as confirmed from petrography; (3) the low levels o f Zr preclude contamination from zircon that might influence the REE data (see below); (4) the Kinsac fluorite is enriched relative to that of the SMB in Sr, Y and Ba, although the Ba and some Sr relates to barite The rare-earth element (REE) chemistry of Kinsac fluorite (Fig.…”

Section: Fluorite Chemistrycontrasting

confidence: 56%

“…12, a log f 0 2 versus pH plot modified from Palmer and Williams-Jones (1996) for conditions of 125°C, with the stability of Eu2+ and Eu3+ from Sveijensky (1984) superimposed. The field for the vein fluids are constrained from the following: (1) trace amounts o f calcite in the veins indicate that at times the fluid overlapped the calcite stability field; (2) the presence of late-stage hematite coating fluorite and absence o f pyrite; and (3) dominance of trivalent Eu in solution, as discussed above.…”

Section: Constraints On Intensive Parameters Of Vein Formationmentioning

confidence: 99%

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Carboniferous barite-fluorite mineralization in the Late Devonian Kinsac Pluton, southern Nova Scotia

Kontak¹,

Horne

Ansdell

et al. 1999

atgeol

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Abundant barite ± fluorite ± quartz veins occur along the eastern margin of the Late Devonian Kinsac Pluton, a peraluminous granite that intruded metasedimentary rocks of the Meguma Group. The barite veins, striking 120° with vertical dip, occur in areas of strongly fractured granite, but the veins are not deformed and may contain lenses of comminuted granite. The veins (< 0.6 m wide) are dominated by coarse, cloudy white barite euhedra with or without a late infill of euhedral clear quartz and pink to dark purple fluorite. 40Ar/39Ar step-wise heating of a K-feldspar megacryst in granite immediately adjacent to a barite vein indicates a 354 Ma plateau age for the high-temperature gas fraction and a ca. 320 Ma age for the lowtemperature gas fraction. The younger age is interpreted to record partial resetting of K-feldspar due to interaction of the mineral with vein-forming fluids.Fluid inclusions (aqueous, L-V types) hosted by vein fluorite have homogenization temperatures of 100° to 130°C. Last melting o f ice indicates salinities of 24 to 28 wt. % equivalent NaCl, but low eutectic temperatures indicate that the fluids are mixed NaCl-CaCl2-FeCl2-MgCl2 brines. Although fluorite-hosted fluid inclusions from the South Mountain Batholith have similar salinities, they homogenize at temperatures of 150° to 160°C. Stable isotopic studies of vein minerals indicate 834Sbarite = +13 ± 2%o, 5 l8Oquartz = +22%oand 8D for fluid inclusion extracts are -123 to -165 %o. The data are interpreted to indicate that: (1) sulphur was derived from dissolution of Windsor Group evaporites rather than from sulphides in basement rocks; (2) the 5 l8Owater of the veins was +8 to +12 %o for 100° to 150°C, which is consistent with either a basinal or metamorphic fluid; (3) the fluids interacted with organic matter to generate the low 8D values. Measured 87Sr/86Sr on barite (0.7120; n=2) and fluorite (0.7086) indicate that the fluids exchanged with a radiogenic source, either the Horton Group or the Meguma Group being the most likely reservoir.Collectively the data indicate vein formation during the Early Carboniferous, when the study area was buried under ca. 2-3 km of Carboniferous strata which have subsequently been eroded. Basinal-type fluids were focused into zones of extension which opened as a result of high Pfluld, in concert with sinistral movement on NW-trending faults that crosscut the Meguma Terrane.On trouve une abondance de filons de barytine ± fluorite ± quartz le long de la marge orientale du pluton du Devonien superieur de Kinsac, granite hyperalumineux qui s'est introduit dans des roches metasedimentaires du groupe de Meguma. Les filons de barytine, orientes selon un pendage vertical de 120°, se trouvent dans des zones de granite fortement fracturees, mais ils ne sont pas deformes et ils pourraient renfermer des lentilles de granite fragments. Les filons (< 0,6 m) sont domines par la presence de barytine automorphe blanc trouble, grossiere, avec ou sans remplissage tardif de quartz transparent automorphe et de fluorite rose a...

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Section: Fluorite Chemistrycontrasting

confidence: 56%

Section: Constraints On Intensive Parameters Of Vein Formationmentioning

confidence: 99%

Carboniferous barite-fluorite mineralization in the Late Devonian Kinsac Pluton, southern Nova Scotia

Kontak¹,

Horne

Ansdell

et al. 1999

atgeol

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“…The association between carbonatite and fluorite is well recognized [28] [29]. Economic fluorite deposits associated with carbonatite complexes are contact and late stage hydrothermal deposits.…”

Section: Fluorite Deposits Associated With Carbonatitesmentioning

confidence: 99%

“…Some late stage carbonatite hosted fluorite deposits were also interpretated through fluid inclusion data which shows its deposition from hydrothermal solutions that evolved from magma chamber which produce carbonatite intrusions [31]. Theory of the mixing of magmatic fluorine-rich fluids with calcium-rich formation water in the sedimentary country rocks giving rise to carbonatite associated deposits have also been proposed by different workers [29] [30]. In such deposits numerous veins of fluorite with barite, chalcopyrite, dickite, galena and pyrite occur at the contact of carbonatite with fenitized sedimentary rocks.…”

Section: Fluorite Deposits Associated With Carbonatitesmentioning

confidence: 99%

A New Classification Scheme of Fluorite Deposits

Magotra¹,

Namga²,

Singh³

et al. 2017

IJG

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Fluorite deposits occur in a variety of geologic environments throughout the globe. It may occur as the main or only economically recoverable ore mineral in deposits or may present as the accessory gangue minerals with other ores. It is therefore necessary to understand various genetic types of the fluorite deposit. The present paper synthesises the information of some of the known fluorite mineralisation from the world so that an understanding of them can help in establishing reliable criteria for further search of fluorite deposit. On the basis of a combination of geological background information and fluorite geochemistry, a new classification scheme is proposed.

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“…An important modification of this technique that others might consider where appropriate is to insert under the fluid-inclusion chip a silica plate, and decrepitate onto this substrate. This modification will permit analysis of a Ca-rich fluid inclusion hosted by, for example, a Ca-rich phase such as fluorite, which was done by Palmer & Williams-Jones (1996).…”

Section: Analytical Techniquesmentioning

confidence: 99%

Analysis of Evaporate Mounds as a Complement to Fluid-Inclusion Thermometric Data: Case Studies From Granitic Environments in Nova Scotia and Peru

Kontak¹

2004

The Canadian Mineralogist

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The bulk composition of fluid inclusions is generally determined by using the temperature of ice melting (i.e., freezing-point depression of H 2 O-NaCl) and relating this to the ice-melting curve in the two-component system H 2 O-NaCl. In reality, natural systems are more complex. Therefore, the bulk composition is referred to as equivalent wt.% NaCl to account for the presence of other, generally undetermined, cations (e.g., K, Ca, Fe, Mn, Mg). Inferences of a more complex chemical composition are generally made on the basis of the depression of the eutectic temperature for the H 2 O-NaCl system (-21.2°C), the other common solutes being CaCl 2 , MgCl 2 , and FeCl 2 . Such an approach is qualitative at best, and the inherent problem of metastability invites caution. An alternative, relatively simple and cost-effective method among the many analytical methods available, is to artificially decrepitate fluid inclusions and analyze the resulting evaporate mounds with an electron microprobe equipped with an imaging system. To illustrate the potential of the method, three granitic environments, in Nova Scotia and in Peru, were chosen, two mineralized (Sn, Cu, Zn) and one barren (tourmaline pegmatite). Standard fluid-inclusion thermometric data have been integrated with compositions determined from evaporate mounds in the same suite of samples. The following points emerge: (1) the inclusions are invariably multi-component, being dominated by Na-K-Ca, but in consistently different proportion that reflect protracted fluid:rock interaction and mixing of reservoirs; (2) the low first-melting temperatures (i.e., <-50°C) do not unequivocally indicate the presence of CaCl 2 in solution; (3) high concentrations of Fe and Mn are common within the mineralized systems examined, in addition to lesser amounts of Sr, Ba, P and Zn, and (4) the two methods complement each other, together providing a much more comprehensive account of the nature of the fluid and its evolution in space and time.Keywords: fluid inclusions, evaporate mounds, granites, pegmatites, tin mineralization. Nova Scotia, Peru. SOMMAIRELa composition globale de la phase fluide piégée dans les cristaux est généralement établie au moyen de la température de fusion de la glace, c'est-à-dire, l'abaissement du point de congélation de l'eutectique du système H 2 O-NaCl, mis en relation avec la courbe décrivant la fusion de la phase solide dans le système binaire H 2 O-NaCl. En fait, les systèmes naturels sont plus complexes. Pour cette raison, la composition globale du fluide est exprimée en termes d'équivalents de NaCl afin de rendre compte d'autres cations, non déterminés, par exemple K, Ca, Fe, Mn, Mg. Des conclusions à propos de la composition chimique plus complexe sont généralement faites pour rendre compte de l'abaissement de l'eutectique en dessous de -21.2°C, sa valeur dans le système H 2 O-NaCl. Les autres solutés courants sont CaCl 2 , MgCl 2 , et FeCl 2 . Une telle approche est définitivement qualitative, et le problème de métastabilité mérite une att...

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Genesis of the carbonatite-hosted fluorite deposit at Amba Dongar, India; evidence from fluid inclusions, stability isotopes, and whole rock-mineral geochemistry

Cited by 75 publications

References 19 publications

Carboniferous barite-fluorite mineralization in the Late Devonian Kinsac Pluton, southern Nova Scotia

Carboniferous barite-fluorite mineralization in the Late Devonian Kinsac Pluton, southern Nova Scotia

A New Classification Scheme of Fluorite Deposits

Analysis of Evaporate Mounds as a Complement to Fluid-Inclusion Thermometric Data: Case Studies From Granitic Environments in Nova Scotia and Peru

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