Sequence of mineral assemblages in differentiated granitic pegmatites

Norton, J.J.

doi:10.2113/gsecongeo.78.5.854

Cited by 50 publications

(14 citation statements)

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“…Sodium-rich alkali feldspar may crystallize from a magma enriched in sodium or, alternatively, may be formed as a replacement product by the interaction of sodium-bearing hydrothermal fluids with a consolidated granite. Most examples for the magmatic origin of sodic granite are to be found in the literature in the West dealing with the aplite-pegmatite association (Jahns and Tuttle 1963;Jahns and Burnham 1969;~ern~ et al 1981;Jahns 1982;Norton 1983;Burnham and Nekvasil 1986;Stern et al 1986). There is a great deal of Soviet literature on sodic rare-metal granitoids of metasomatic origin or "apogranites" (Beus et al 1962;Beus 1970;Sitnin 1970;Severov et al 1977;Ginzburg and Fel'dman 1977); but sodic rare-metal granites of magrnatic origin are rarely described (Kovalenko et al 1970;Kovalenko 1978).…”

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confidence: 99%

Geochemical criteria for distinguishing magmatic and metasomatic albite-enrichment in granitoids ? examples from the Ta-Li granite Yichun (China) and the Sn-W deposit Tikus (Indonesia)

Schwartz

1992

Mineral. Deposita

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Two examples ofalbite-rich granitoids of different genesis are discussed: the Ta-Li granite at Yichun (China) exhibits dominantly igneous textures, and the sodium-enrichment zone in biotite granite of the Sn-W deposit at Tikus is characterized by metasomatic textures. The Yichun stock shows a magmatic evolution from biotite-muscovite granite to lepidolite granite with an increase of Na20 and F concentrations and a decrease of CaO and Sr concentrations. The composition of the different granite phases is close to pseudoternary minima in the haplogranite-H20(-Li-F) system. The composition of the F-rich albitization zone at Tikus deviates strongly from the pseudoternary minima and shows a tendency to become monomineralic (nearly pure albitite). CaO and Sr concentrations are increased or remain unchanged with respect to the unaltered biotite granite at Tikus. Albitization produced by fluid-rock interaction in F-rich systems is characterized by that CaO or Sr released by the breakdown of plagioclase in the granite protolith, are fixed in newly formed fluorite or albite, respectively. aluminous granitoids) as well as REE, Y, Nb and Zr (peralkaline granitoids).Apart from textural studies, the geochemical characterization of the granitoids is crucial for distinguishing sodium-enrichment in the magmatic stage from metasomatic sodium-enrichment. This can be demonstrated with two examples: the rare-metal granite at Yichun (China) crystallized from a sodium-rich magma, and the albitized granite associated with Sn-W greisen at Tikus (Indonesia) which is an example of albite deposition by the interaction of sodium-bearing fluids within a consolidated granite along a tectonized zone.

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confidence: 99%

Geochemical criteria for distinguishing magmatic and metasomatic albite-enrichment in granitoids ? examples from the Ta-Li granite Yichun (China) and the Sn-W deposit Tikus (Indonesia)

Schwartz

1992

Mineral. Deposita

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“…Norton (1983) stressed that these are mineral assemblages, and that they do not correspond one-for-one with the structural zones shown in figure 14. Working inward, the Norton (1983) The above list covers only the major mineral phases, those comprising at least 5 percent of the rock by volume. The plagioclase-rich outer units may include accessory beryl, garnet, tourmaline, apatite, and (or) columbite.…”

Section: Zoning Patternsmentioning

confidence: 95%

“…Norton (1983) presented a scheme describing the mineralogical zonation of lithiumbearing pegmatites, modified from a similar one by Cameron and others (1949). Norton (1983) stressed that these are mineral assemblages, and that they do not correspond one-for-one with the structural zones shown in figure 14. Working inward, the Norton (1983) The above list covers only the major mineral phases, those comprising at least 5 percent of the rock by volume.…”

Section: Zoning Patternsmentioning

confidence: 99%

“…At Tanco, it comprises about 33 percent of the rock and at Tin Mountain about 34 percent. Norton (1983) noted that not all zones of pure quartz in pegmatites are at the physical core of the intrusive body. Silica occurs as the lower-temperature form, α-quartz; only in exceptional cases of high temperature and low pressure crystallization does β-quartz form (Martin, 1982).…”

Section: Mineralogy and Mineral Assemblagesmentioning

confidence: 99%

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Mineral-deposit model for lithium-cesium-tantalum pegmatites

Bradley¹,

McCauley²,

Stillings³

2017

Scientific Investigations Report

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“…Guilbert and Park 1986). The presence of alteration zone coupled with rare miner- als such as elbaite, manganotantalite and microlite, among others, defi ne this as a zoned, complex pegmatitic body, according to of Cameron et al (1949) and Norton (1983) criteria.…”

Section: The Alto Quixaba Pegmatitementioning

confidence: 99%

Chemical and mineralogical characterization of elbaites from the Alto Quixaba pegmatite, Seridó province, NE Brazil

Ferreira

Soares

et al. 2005

An. Acad. Bras. Ciênc.

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The Alto Quixaba pegmatite, Seridó region, northeastern Brazil, is a 60 • /80 • SW-trending subvertical dike discordantly intruded into biotite schists of the Upper Neoproterozoic Seridó Formation. It has three distinct mineralogical and textural zones, besides a replacement body that cuts the pegmatite at its central portion and in which occur, among other gem minerals, colored elbaites. Elbaites usually occur as prismatic crystals, elongate according to the c-axis, with rounded faces and striations parallel to this axis. Optically, crystals are uniaxial negative with strong pleochroism; refractive index extraordinary axis = 1.619-1.622 and ordinary axis = 1.639-1.643, birefringence between 0.019 and 0.021, average relative density of 3.07, and the following unit cell parameters: ao = 15.845 Å, co = 7.085 Å and V = 1540.476 Å. There is alkali defi ciency in the X site of 12-17%. The elbaites are relatively enriched in MnO (1.69 to 2.87%) and ZnO (up to 2.98%).

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Sequence of mineral assemblages in differentiated granitic pegmatites

Cited by 50 publications

References 0 publications

Geochemical criteria for distinguishing magmatic and metasomatic albite-enrichment in granitoids ? examples from the Ta-Li granite Yichun (China) and the Sn-W deposit Tikus (Indonesia)

Geochemical criteria for distinguishing magmatic and metasomatic albite-enrichment in granitoids ? examples from the Ta-Li granite Yichun (China) and the Sn-W deposit Tikus (Indonesia)

Mineral-deposit model for lithium-cesium-tantalum pegmatites

Chemical and mineralogical characterization of elbaites from the Alto Quixaba pegmatite, Seridó province, NE Brazil

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