Геохимия Стабильных Изотопов Кислорода И Водорода Корундоносных Пород И Минералов Северной Карелии Как Индикатор Необычных Условий Формирования

Высоцкий, С. В.; Ignat’ev, A. V.; Левицкий, В. И.; Нечаев, В П; Веливецкая, Т. А.; Яковенко, В В

doi:10.7868/s0016752514090106

Cited by 4 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Другая проблема, связанная с корундсодержащими породами -происхождение необычного изотопного состава кислорода и водорода: δ 18 О в них достигает -27‰, Δ 17 O до -14‰, а δD опускается до -235‰ (проявление Хитоостров) (Бакшеев и др., 2006;Устинов и др., 2008;Крылов и др., 2012;Высоцкий и др., 2014; компьютерной программе TWQ (версия 2.02b) . Одно из достоинств метода TWEEQU состоит в том, что он позволяет также оценить равновесность наблюдаемой в породе минеральной ассоциации.…”

Section: аннотацияunclassified

Distribution of rare-earth elements in rock-forming minerals of corundum-bearing rocks of the Khitoostrov deposit (North Karelia)

Akimova¹,

Скублов²

2021

Vestnik SPbSU. Earth Sciences

View full text Add to dashboard Cite

The distribution of rare-earth elements (SIMS method) in minerals from the rocks of the Khitoostrov occurrence (Belomorian mobile belt of Eastern Fennoscandia) was studied: corundum-bearing metasomatites with anomalous isotopically light oxygen and hydrogen and garnet amphibolites after gabbro with normal isotopic composition. The study was accompanied by estimates of P-T parameters of rock formation using multi-equilibrium thermobarometry (TWEEQU method). Temperatures calculated for garnet amphibolites after gabbro fall within the range of 730–770 ° C, pressures - 13–14 kbar; for corundum-bearing rocks, temperatures were 680–710 ° C, pressures - 6.5–7.5 kbar. Corundum-bearing rocks were formed at slightly lower temperatures and at significantly lower pressures than garnet amphibolites after gabbro. The REE distribution spectra in garnets from apogabbroic amphibolites are characterized by a clearly pronounced slope from light to heavy REE, while in garnets from corundum-bearing rocks they have a less pronounced positive slope, which is associated with a noticeable enrichment of garnets in LREE and an insignificant depletion of HREE. Calcium amphiboles from corundum-bearing rocks are significantly enriched in rare-earth elements as compared to amphiboles from garnet amphibolites after gabbro, especially LREE (by more than an order of magnitude) and, to a lesser extent, MREE. Plagioclases from corundum-bearing rocks are also enriched in LREE against the background of garnet amphibolites. Thus, in all the studied minerals of corundum-bearing rocks LREE enrichment is recorded. It isn’t manifested in the minerals of amphibolites and, obviously, isn’t related to the difference in P-T parameters of rock formation. Consequently, LREE was transferred by a specific fluid during mineral-forming processes, which led to the formation of metasomatites with an anomalous isotopic composition of oxygen and hydrogen.

show abstract

Section: аннотацияunclassified

Distribution of rare-earth elements in rock-forming minerals of corundum-bearing rocks of the Khitoostrov deposit (North Karelia)

Akimova¹,

Скублов²

2021

Vestnik SPbSU. Earth Sciences

View full text Add to dashboard Cite

show abstract

Voimakan deposit of dolomite type nephrite, Middle-vitim mountain country: formation conditions

Kislov,

Goncharuk,

Vanteev

et al. 2024

Geologiâ rudnyh mestoroždenij

View full text Add to dashboard Cite

The Voimakan deposit of dolomite type nephrite has been investigated in order to clarify the features of its formation. 12 samples of nephrite and 5 samples of host rocks were studied. A binocular stereomicroscope, a gemological flashlight and a polarizing petrographic microscope were used. The contents of macro- and micro-components, the isotopic composition of oxygen were determined. Nephrite is light salad, salad, gray-salad and brown (honey). It forms separations in calcite-tremolite skarn bodies at the contact of dolomite marble and amphibolite transformed into epidote-tremolite skarn. The value of δ 18 O of nephrite is –18.5 ÷ –18.8%; calcite-tremolite skarn –17.4%; epidote-tremolite scarn –4.4, 2.6%; dolomite 26.1%. Nephrite meets the requirements for gemstone raw materials. Diopsidite with nephrite lenses and interlayers can be used for carving multicolored products or inlays. The green shade of nephrite increases with an increase in the Fe 2+ content. The brown color of nephrite is determined by Fe 3+ in the tremolite structure. The dolomite type of nephrite is confirmed by the ratio of Mg and Fe, a reduced content of Cr, Ni, Co, an increased content of F and the ratio of Sr to Ba, and the nature of the REE distribution. The distribution of REE in nephrite is determined by the composition of the initial dolomite under the influence of epidote-tremolite scarn. The source of abnormally isotopically light oxygen of nephrite is a meteoric fluid depleted in 18 O as a result of dolomite decarbonation. Granite only provides regional heating, activating the fluid. Both metasomatic and metamorphic processes were involved in the nephrite formation and transformation. The formation of nephrite is associated with the formation of calcite-tremolite and epidote-tremolite skarns. Tectonic stresses caused the crushing of rocks, facilitating the penetration of fluid, provided the formation of a nephrite cryptocrystalline tangled fibrous structure. But further regressive metamorphism led to the development of chlorite and talc, which worsened the nephrite quality.

show abstract

Metasomatic Transformation of Amphibolites into Corundum-Bearing Plagioclasites: Zoning, Numerical Model of the Process (on the Example of the Unique Khitostrov Mineral Deposit, Fennoscandian Shield)

Bushmin,

Kol’tsov,

Lebedeva

et al. 2023

Petrologiâ

View full text Add to dashboard Cite

The paper presents the results of a study of desilicated rocks of the middle crust at the level of amphibolite facies using the example of corundum-bearing plagioclasites developing over the metabasites at the unique Khitostrov mineral deposit in the Belomorian-Lapland orogen of the Fennoscandian Shield. The main attention is paid to new geological data, documentation and analysis of metasomatic zoning, determination of the P-T conditions of its formation, and a model of the metasomatic process.

show abstract

Геохимия Стабильных Изотопов Кислорода И Водорода Корундоносных Пород И Минералов Северной Карелии Как Индикатор Необычных Условий Формирования

Cited by 4 publications

References 0 publications

Distribution of rare-earth elements in rock-forming minerals of corundum-bearing rocks of the Khitoostrov deposit (North Karelia)

Distribution of rare-earth elements in rock-forming minerals of corundum-bearing rocks of the Khitoostrov deposit (North Karelia)

Voimakan deposit of dolomite type nephrite, Middle-vitim mountain country: formation conditions

Metasomatic Transformation of Amphibolites into Corundum-Bearing Plagioclasites: Zoning, Numerical Model of the Process (on the Example of the Unique Khitostrov Mineral Deposit, Fennoscandian Shield)

Contact Info

Product

Resources

About