Primary allanite in vitrophyric rhyolites from the Tweed Shield Volcano, north-eastern New South Wales

Duggan, M. B.

doi:10.1180/minmag.1976.040.314.17

Cited by 8 publications

(4 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several reports already exist in the literature of phenocrystic allanite in sparsely porphyritic rhyolites (Branch, 1966;Izett and Wilcox, 1968;Duggan, 1976;Hildreth, 1979) and indeed it has t~ Copyright the Mineralogical Society been previously reported in the Sandy Braes obsidian (Cameron and Sabine, 1969;Sabine, 1970) although this occurrence apparently escaped the attention of Duggan (1976).…”

mentioning

confidence: 92%

See 1 more Smart Citation

Rare-earth partition between allanite and glass in the obsidian of Sandy Braes, Northern Ireland

Brooks¹,

Henderson

Rønsbo³

1981

Mineral. mag.

View full text Add to dashboard Cite

ABSTRACT. Allanite phenocrysts and co-existing glass from the perlitic obsidian of Sandy Braes have been analysed for nine rare earths (RE), uranium, and thorium by instrumental neutron activation analysis and for the major elements by electron microprobe. The chondritenormalized RE plot for the allanite shows a steep slope with a negative Eu anomaly. Allanite/glass partition coefficients show a smooth variation with ionic radius (except for Eu), the variation spanning two orders of magnitude. The partitioning behaviour, which is distinct from that shown by the RE in sphene, apatite, and zircon, can be explained by the allanite structure. The pronounced affinity of the light RE for allanite makes this an important mineral in considerations of RE concentrations during the evolution of granitic liquids.

show abstract

mentioning

confidence: 92%

“…Average of two analyses of allanite-bearing rhyolites from the Tweed Shield Volcano of New South Wales, Duggan (1976Duggan ( ). (1976, which are also regarded as being extreme differentiates of a tholeiitic magma.…”

mentioning

confidence: 99%

Rare-earth partition between allanite and glass in the obsidian of Sandy Braes, Northern Ireland

Brooks¹,

Henderson

Rønsbo³

1981

Mineral. mag.

View full text Add to dashboard Cite

show abstract

“…Allanite, an epidote group mineral rich in REE, is a common accessory phase in granites, granodiorites, monzonites, syenites and pegmatites (see Deer et al 1962), and occurs as phenocrysts also in acid volcanic rocks such as rhyolites (Duggan 1976) and perlitic obsidian (Brooks et al 1981). Further, it is found in schists and gneisses (see Deer et al 1962).…”

Section: Introductionmentioning

confidence: 99%

Zirconolite, allanite and hoegbomite in a marble skarn from the Bergell contact aureole: implications for mobility of Ti, Zr and REE

Gieré¹

1986

Contr. Mineral. and Petrol.

106

View full text Add to dashboard Cite

Abstract. Zirconolite, allanite and hoegbomite are present as accessory phases in a metasomatically altered spinel-calcite-marble from the contact with the Bergell intrusives (Switzerland/Italy). Textural relationships indicate a stepwise alteration of spinel to 1) hoegbomite or corundum + magnetite, 2) margarite and 3) chlorite. Replacement of spinel by hoegbomite can be described by the substitution 1.94(M g2 + F e2 + z n 2 + m n 2+ ca2+),,T•4+ + 0.12(OH ) where Al' and Fe' are held constant. The average composition of the Bergell hoegbomites is given by the formula Fe u 7 Mg0.69 Zn 0.04 Ti 0.17 A1 3.94 F4.+060 7.98( OH )0.02 and seems to be imposed by the composition of pre-existing spinel. During the first two steps of spinel alteration, calcite was replaced by anorthite + phlogopite, and the rare earth element(REE)-bearing minerals zirconolite, allanite and sphene were formed. Allanites have characteristic chondrite-normalized REE patterns with enrichment in the light REE. The zirconolite patterns show a marked increase in concentration from La to Ce, followed by an almost constant section. Sphene lacks detectable La, and its REE patterns vary from grain to grain. Contemporaneous formation of phlogopite, REE-bearing minerals and hoegbomite during replacement of the spinel-calcite-marble indicates that the metamorphic fluid introduced potassium along with REE and other high valence cations (Ti', Zr4+ , U4+, Th', Nb', Y 3+ ) possibly as polynuclear complexes. The abundance of fluorine-bearing phlogopite and fluor-apatite as well as their close association with REE-bearing minerals and hoegbomite suggests F -and P01 -as likely ligands for complexing of the above mentioned elements.

show abstract

“…Although allanite is considered as a rather rare mineral in volcanic rocks, it has been found in trace amounts in ash-fall and ash-flow tufts (Izett and Wilcox, 1968), as phenocrystic allanite in porphyritic rhyolites (Branch, 1966;Duggan, 1976;Hildreth, 1979) and in obsidian (Cameron and Sabine, 1969;Sabine, 1970;Brooks et al, 1981).…”

Section: Introductionmentioning

confidence: 99%

Primary allanite in andesitic rocks from the Poros Volcano, Greece

Mitropoulos

1987

Mineral. mag.

View full text Add to dashboard Cite

Primary allanite crystals occurring in andesitic rocks from Poros, NE Peloponnese, Greece were studied. Although the allanite shows high REE content, its presence does not affect the whole-rock REE content of the andesite. It is suggested that the formation of allanite crystals reflects the crystallization history of the andesitic rocks where allanite occurs. These andesitic rocks are the most basic rocks in which allanite has been reported.

show abstract

Primary allanite in vitrophyric rhyolites from the Tweed Shield Volcano, north-eastern New South Wales

Cited by 8 publications

References 3 publications

Rare-earth partition between allanite and glass in the obsidian of Sandy Braes, Northern Ireland

Rare-earth partition between allanite and glass in the obsidian of Sandy Braes, Northern Ireland

Zirconolite, allanite and hoegbomite in a marble skarn from the Bergell contact aureole: implications for mobility of Ti, Zr and REE

Primary allanite in andesitic rocks from the Poros Volcano, Greece

Contact Info

Product

Resources

About