Relationships between monazite, apatite and chevkinite-group minerals in the rhyolitic Joe Lott Tuff, Utah, USA

Galanciak, J. and Bagiński, B. and Macdonald, R. and Belkin, H.E. and Kotowski, J. and Jokubauskas, P. (2020) Relationships between monazite, apatite and chevkinite-group minerals in the rhyolitic Joe Lott Tuff, Utah, USA. Lithos, 354-35 (2). ISSN 0024-4937

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Abstract

The high-silica rhyolitic Joe Lott Tuff was erupted at 19.2 ± 0.4 Ma from the Mount Belknap caldera in Utah, USA. Despite having a volume of ~150 km3 it is compositionally homogeneous and contains ≤3 modal% phenocrysts. The tuff also shows two very unusual aspects of the REE-bearing phases, monazite and the chevkinite-group minerals (CGM): (i) the presence of perrierite-(Ce) in a high-silica rhyolite, and (ii) the replacement of CGM in the stratigraphic sequence by monazite, with a subsequent return to a CGM. Evidence from CGM distribution and variations in monazite and apatite-group composition with stratigraphic height in the deposit are used to infer that prior to eruption the magma was compositionally zoned, the zonation being partially obliterated by convective overturn in the reservoir.

Item Type:
Journal Article
Journal or Publication Title:
Lithos
Additional Information:
This is the author’s version of a work that was accepted for publication in Lithos. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Lithos, 354-355, 2, 2020 DOI: 10.1016/j.lithos.2019.105349
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1906
Subjects:
ID Code:
140386
Deposited By:
Deposited On:
20 Jan 2020 11:35
Refereed?:
Yes
Published?:
Published
Last Modified:
28 Mar 2020 06:31