Ree minerals of alkaline metasomatic rocks in the Main Sayan Fault

Савельева, В. Б.; Карманов, Н. С.

doi:10.1134/s1075701508080035

Cited by 8 publications

(5 citation statements)

References 5 publications

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“…The replacement of allanite by REE-carbonates has been described by Berger et al (2008), Savel'eva and Karmanov (2008) and Papoutsa and Pe-Piper (2013) and is at least consistent with allanite being unstable under conditions of high X(CO 2 ). …”

Section: Relationships Between Cgm Composition and Nature Of Accessoriesmentioning

confidence: 93%

Hydrothermal alteration of a chevkinite-group mineral to a bastnäsite-(Ce)-ilmenite- columbite-(Fe) assemblage: interaction with a F-, CO2-rich fluid

et al. 2015

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The results are presented of a textural and mineral chemical study of a previously undescribed type of hydrothermal alteration of chevkinite-(Ce) which occurs in a syenitic pegmatite from the Vishnevye Mountains, Urals Region, Russia. The progressive alteration of the chevkinite to a bastnäsite-(Ce)-ilmenite-columbite-(Fe) assemblage through a series of texturally complex intermediate stages is described and electron microprobe analyses are given of all the major phases. Unusual Nb±Th-rich phases formed late in the alteration sequence provide evidence of local Nb mobility. The main compositional fluxes are traced, especially of the REE, HFSE, Th and U. It appears that almost all elements, with the exception of La, released from the chevkinite-(Ce) were reincorporated into later phases, such that they did not leave the alteration crust in significant amounts. The hydrothermal fluids are inferred to have been F-and CO 2 -rich, with variable levels of Ca activity, and with fO 2 mainly between the nickelnickel oxide and magnetite-hematite buffers. This occurrence represents a new paragenesis for a columbite-group mineral.

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Section: Relationships Between Cgm Composition and Nature Of Accessoriesmentioning

confidence: 93%

Hydrothermal alteration of a chevkinite-group mineral to a bastnäsite-(Ce)-ilmenite- columbite-(Fe) assemblage: interaction with a F-, CO2-rich fluid

et al. 2015

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“…In contrast, Jiang (2006) reported fractionation of Nd from La during alteration of chevkinite-(Ce) from the Shuiquangou syenite, northern China. Alteration of chevkinite-(Ce) in metasomatites of the Main Sayan Fault resulted in decreases in La/Ce and La/Nd and increases in La/Y ratios (Savel'eva and Karmanov, 2008). Alteration of chevkinite-(Ce) in 160b/62 (crystal 1) resulted in no fractionation of the LREE; [La/Nd] cn ratios, for example, were constant at 1.4.…”

Section: Behaviour Of Nb and Th And Ree Fractionation During Alterationmentioning

confidence: 97%

Hydrothermal alteration of chevkinite-group minerals: products and mechanisms. Part 1. Hydration of chevkinite-(Ce)

et al. 2015

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Samples from Russia and Scotland are used to examine the interaction of the REE-Ti silicate chevkinite-(Ce) with hydrothermal fluids. Altered zones in crystals are distinguished by using areas of low intensity on backscattered-electron images, low analytical totals, increasingly large departures from stoichiometry and, in some cases, the presence of micropores. Initial alteration of the chevkinite results in strong Ca enrichment. With increasing degrees of alteration, Ca abundances drop sharply, as do those of the REE, Fe and Si. In contrast, Ti levels increase strongly, usually accompanied by higher Nb ± Th levels. The most altered zones contain up to 36 wt.% TiO2 and the formula cannot be expressed in the standard chevkinite formula. In detail, samples follow different alteration trends, presumably reflecting different P, T, fO2 and fluid composition. The Ti enrichment may have been related to a reaction front of dissolution-reprecipitation passing through the outer zones of the original chevkinite, leaving behind a reprecipitated Ti-enriched phase which may or may not be chevkinite.

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“…Also shown are members of the chevkinite group currently accepted by the IMA: M, maoniupingite-(Ce) (Shen et al, 2005); C, chevkinite-(Ce) (as redefined by Nickel and Mandarino, 1987; analysis from Macdonald and Belkin, 2002); D, dingdaohengite-(Ce) (Xu et al, 2008); Po, polyakovite-(Ce) (Popov et al, 2001); Pe, perrierite-(Ce) (this paper, Table 3); SC, strontio-chevkinite (Haggerty and Mariano, 1983); R, rengeite (REE-free variety; Miyajima et al, 2001); Mb, matsubaraite (Miyajima et al, 2002). Data for published analyses of chevkinite-group minerals are from the compilation by Macdonald and Belkin (2002), updated with analyses from Barritt (1983), Wang et al (2001), Yang et al (2002), Troll et al (2003), Sokolova et al (2004), Yakovenchuk et al (2005), Zhang et al (1995), Jiang (2006), Monchoux et al (2006), Hokada (2007), Horaiova et al (2007, Vlach and Gualda (2007), Carlier and Lorand (2008), Mashima et al (2008), Savel'eva andKarmanov (2008), Shimazaki et al (2008), Xu et al (2008) and Belkin et al (2009).…”

Section: Selected Compositional Features Of New Analysesmentioning

confidence: 99%

Compositional variation in the chevkinite group: new data from igneous and metamorphic rocks

Macdonald¹,

Belkin²,

Wall³

et al. 2009

Mineral. mag.

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Electron microprobe analyses are presented of chevkinite-group minerals from Canada, USA, Guatemala, Norway, Scotland, Italy and India. The host rocks are metacarbonates, alkaline and subalkaline granitoids, quartz-bearing pegmatites, carbonatite and an inferred K-rich tuff. The analyses extend slightly the range of compositions in the chevkinite group, e.g. the most MgO-rich phases yet recorded, and we report two further examples where La is the dominant cation in the A site. Patchily- zoned crystals from Virginia and Guatemala contain both perrierite and chevkinite compositions. The new and published analyses are used to review compositional variation in minerals of the perrierite subgroup, which can form in a wide range of host rock compositions and over a substantial pressure- temperature range. The dominant substitutions in the various cation sites and a generalized substitution scheme are described.

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Ree minerals of alkaline metasomatic rocks in the Main Sayan Fault

Cited by 8 publications

References 5 publications

Hydrothermal alteration of a chevkinite-group mineral to a bastnäsite-(Ce)-ilmenite- columbite-(Fe) assemblage: interaction with a F-, CO2-rich fluid

Hydrothermal alteration of a chevkinite-group mineral to a bastnäsite-(Ce)-ilmenite- columbite-(Fe) assemblage: interaction with a F-, CO2-rich fluid

Hydrothermal alteration of chevkinite-group minerals: products and mechanisms. Part 1. Hydration of chevkinite-(Ce)

Compositional variation in the chevkinite group: new data from igneous and metamorphic rocks

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