Igneous rocks with high Ta concentrations share a number of similarities such as high Ta/Nb, low Ti, LREE and Zr concentrations and granitic compositions. These features can be traced through fractionated granitic series. Formation of Ta-rich melts begins with anatexis in the presence of residual biotite, followed by magmatic crystallization of biotite and muscovite. Crystallization of biotite and muscovite increases Ta/Nb and reduces the Ti content of the melt. Titanium-bearing oxides such as rutile and titanite are enriched in Ta and have the potential to deplete Ta at early stages of fractionation. However, mica crystallization suppresses their saturation and allows Ta to increase in the melt. Saturation with respect to Ta and Nb minerals occurs at the latest stages of magmatic crystallization, and columbite can originate from recrystallization of mica. We propose a model for prediction of intrusion fertility for Ta.

Item Type:	Refereed Article
Keywords:	rare metal, deposit, biotite, muscovite, granite fractionation, anatexis, granite classification
Research Division:	Earth Sciences
Research Group:	Geology
Research Field:	Igneous and Metamorphic Petrology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Earth Sciences
Author:	Stepanov, A (Mr Sasha Stepanov)
Author:	Meffre, S (Dr Sebastien Meffre)
Author:	Davidson, P (Dr Paul Davidson)
ID Code:	94714
Year Published:	2014
Web of Science® Times Cited:	17
Deposited By:	Centre for Ore Deposit Research - CODES CoE
Deposited On:	2014-09-16
Last Modified:	2015-03-05
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