Potassic alkaline-basic and alkaline volcanic rocks of Southern Mongolia

Baskina, V. A.; Volchanskaya, I. K.; Frikh-Khar, D. I.; Yarmolyuk, V. V.

doi:10.1080/00206817809471519

Cited by 3 publications

(3 citation statements)

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“…In addition, celestine occurrences can be as hydrothermal veins associated with mafic volcanism (e.g. Baskina et al , 1978; Brigatti et al , 1997; Radivojević et al , 2015; Garcia et al , 2016; Tortelli et al , 2022) or basaltic dykes (Anenburg et al , 2014). Occurrences of younger Quaternary celestines comparable to those investigated in southern Libya have been recorded only rarely (e.g.…”

Section: Overview Of Celestine-bearing Environmentsmentioning

confidence: 99%

Characterisation, axial anisotropy, and formation conditions of celestine minerals from the Jabal Eghei (Nuqay) late Neogene – Pleistocene volcanic province, southeastern edge of the Sirt Basin, southern Libya: Constraints on the mineralogical geothermometer

Tančić,

Milošević,

Spahić

et al. 2023

MinMag

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Five celestine crystals were sampled from the (palaeo)surface intervening between the late Miocene to Pleistocene basaltic sequences of the Jabal Eghei (Nuqay) volcanic province in southern Libya and then characterised by applying a combination of the SEM–WDS, ICP/OES, PXRD and IR methods. Colour variations and related minerogenetic frameworks were also investigated. Three samples have greenish-blue-to-blue colour (480.4–482.5 nm), whereas the other two samples have blue–green colour (cyan; 489.1–494.1 nm). The colour purity ranges from 1.36–7.16. Their composition is similar, end-member celestine, in which only 1.6–4.1 at.% of Sr2+ content was substituted by Pb2+ (0.7–0.9 at.%), Ba2+ (0.5–0.7 at.%) and Ca2+ (0.2–0.8 at.%). Three samples contained vacancies, from 1.0 to 1.9 at.%. The content of other chemical elements is minor. The resulting unit-cell parameters have the ranges: a0 = 8.3578(9)–8.3705(6) Å; b0 = 5.3510(5)–5.3568(4) Å; c0 = 6.8683(7)–6.8767(2) Å and V0 = 307.17(5)–308.34(4) Å3. The PXRD and IR results are mainly in accordance with the SEM–WDS results, with a high level of correlation. However, a few discrepancies were found, producing several possible interpretations, the primary cause being a slight unit-cell axial anisotropy i.e. thermal expansion. As a consequence these results yield a new geothermometric tool that is based on the unit-cell axial anisotropy. The celestines investigated were formed during a Miocene intraplate volcanism with basaltic magmas, and associated brines lifted by the structural conduits (normal faults crosscutting the Sirt basin). The Sr-bearing fluids then poured into and over the faulted and fractured lagoon-type gypsum, anhydrite Eocene sediments. The celestine mineralisation formed within a ~368–430 K (~95–157°C) temperature range. The celestine formed at slightly elevated temperature and pressure conditions, close to the shallow subsurface environment (over 250 bars).

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Section: Overview Of Celestine-bearing Environmentsmentioning

confidence: 99%

Characterisation, axial anisotropy, and formation conditions of celestine minerals from the Jabal Eghei (Nuqay) late Neogene – Pleistocene volcanic province, southeastern edge of the Sirt Basin, southern Libya: Constraints on the mineralogical geothermometer

Tančić,

Milošević,

Spahić

et al. 2023

MinMag

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“…The complex consists of Late Paleozoic basic and intermediate volcanic and mixed rocks [2] together with Mesozoic subalkaline intermediate and acid rocks [1,7,8]. The carbonate occurrences are spatially and KULESHOV AND PERVOV probably genetically related to a series of subalkaline rocks produced over a narrow time range of ~ 150 m.y.…”

Section: Geologic Setting and Characteristics Of The Ulugey Complexmentioning

confidence: 99%

“…Some data on the carbon and oxygen isotopic compositions of these rocks were obtained previously [ 1 ]. This paper is the result of a detailed study of the isotopic 3) carbonate-cemented syenite breccias; 4) granosyenites (a-uniformly coarse-grained, b-porphyritic dikes); 5) country rocks; 6) quartz syenite porphyries (a-outer ring intrusive body, b-dikes); 7) syenites (a-mesocratic equigranular, b-leucocratic equigranular, c-porphyritic); 8) trachytes; 9a) sampling points: 1-anal.…”

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confidence: 99%