Some recent advances in the mineralogy and geochemistry of Nb and Ta in rare-element granitic pegmatites

1985 ◽  
Vol 108 (3) ◽  
pp. 499-532 ◽  
Author(s):  
Petr Černý ◽  
T. Scott Ercit
Keyword(s):  
Rare Element ◽  
Granitic Pegmatites ◽  
Recent Advances

LA-ICP-MS U Pb columbite ages and trace-element signature from rare-element granitic pegmatites of the Pampean Pegmatite Province, Argentina

Lithos ◽  
2021 ◽  
Vol 386-387 ◽  
pp. 106001
Author(s):  
Miguel Ángel Galliski ◽  
Albrecht von Quadt ◽  
María Florencia Márquez-Zavalía
Keyword(s):  
Trace Element ◽  
Rare Element ◽  
Granitic Pegmatites ◽  
Icp Ms ◽  
Trace Element Signature

Experimental study of the equilibrium between pollucite, albite and hydrothermal fluid in pegmatitic systems

1990 ◽  
Vol 54 (376) ◽  
pp. 447-454 ◽  
Author(s):  
Ansom Sebastian ◽  
Martine Lagache
Keyword(s):  
Experimental Study ◽  
Hydrothermal Fluid ◽  
Hydrothermal Solution ◽  
Silicate Mineral ◽  
Rare Element ◽  
Granitic Pegmatites

AbstractPollucite is a silicate mineral of the rare element caesium, occurring in granitic pegmatites. Experiments have been carried out at 450, 600, and 750°C, 1.5 kbar, to study the equilibrium between pollucite, albite and the co-existing hydrothermal solution. When pollucite co-exists with albite, the alkaline composition of the solution is buffered. The Cs/Na ratio of the solution has been determined to be 0.11 at 450°C 0.22 at 600°C and 0.23 at 750°C. Pollucite contains about 15 mol.% of sodium, whereas albite is almost purely sodic. In nature, pollucite with more than 82 mol.% caesium has never been found. This can be explained by the absence of solutions in granitic pegmatites having a higher Cs/Na ratio than those determined by us.

scholarly journals Phosphate minerals in granitic pegmatites from the Mount Wills District, north-eastern Victoria

2015 ◽  
Vol 127 (2) ◽  
pp. 55
Author(s):  
Ryan M. Eagle ◽  
William D. Birch ◽  
Stafford McKnight
Keyword(s):  
Hydrothermal Alteration ◽  
Spatial Relationship ◽  
Radiometric Dating ◽  
Metasomatic Alteration ◽  
Rare Element ◽  
Peraluminous Granite ◽  
Granitic Pegmatites ◽  
North Eastern ◽  
Close Spatial Relationship

Tin- and tantalum-bearing LCT-type granitic pegmatites occur in a 45 km long belt between Eskdale and Mount Wills in north-eastern Victoria. Near Mount Wills, several compositionally zoned rare-element pegmatites contain complex assemblages of primary and secondary phosphate minerals, many of which are rare and previously unrecorded in Victoria. The phosphate assemblages can be divided into Al-rich and Fe–Mn-rich suites, in addition to ubiquitous fluorapatite. The Al-rich phosphate suite includes montebrasite, scorzalite, bertossaite and brazilianite. The Fe‒Mn phosphate suite includes heterosite, phosphoferrite, wolfeite, alluaudite (sp.), arrojadite (sp.) and jahnsite (sp.), derived from the metasomatic alteration of primary triplite. Further hydrothermal alteration of this assemblage has resulted in a secondary suite of strengite, rockbridgeite, phosphosiderite, whiteite, jahnsite and whitmoreite forming in etch cavities and fractures. A Late Silurian age of 420±4 Ma was obtained from one of the dykes via CHIME radiometric dating of monazite, suggesting a similar age for the adjacent Mount Wills Granite, which has not been reliably dated. This highly fractionated, peraluminous granite is presumed to be the source of the rare-element pegmatites based on their close spatial relationship.

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