The Gold Flat Tuff, Nevada : Insights into the evolution of peralkaline silicic magmas

MacDonald, Raymond and Bagiński, Bogusław and Belkin, Harvey and White, John and Noble, D.C. (2019) The Gold Flat Tuff, Nevada : Insights into the evolution of peralkaline silicic magmas. Lithos, 328-32. pp. 1-13. ISSN 0024-4937

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The Gold Flat Tuff is the youngest (9.15 Ma) ash-flow sheet erupted from the Black Mountain Volcanic Centre, southwest Nevada, USA. This paper explores some aspects of the very complex nature of the tuff's magmatic plumbing system. The main body of the deposit is a mixed magma product, comprising pantelleritic and comenditic melts derived from independently evolving reservoirs, and antecrysts and enclaves derived from a range of basic to intermediate sources. Metre-scale cognate xenoliths point to the presence of alkali feldspar accumulation zones. The pantellerite contains phenocrysts of fluorite and chevkinite-(Ce). The inferred intermediate magma component contains perrierite-(Ce) phenocrysts. The pantellerite has unusually high contents of F (≤2.2 wt%), F + Cl (≤2.9 wt%) and ZrO 2 (≤1.04 wt%). The high halogen contents may have influenced the evolution of the strongly peralkaline magma. The crystallization conditions are poorly constrained but those for the pantelleritic magma may have been close to water-saturation (>4 wt% melt water) at temperatures ~740 °C and fO 2 around FMQ.

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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, 328-329, 2019 DOI: 10.1016/j.lithos.2019.01.017
Uncontrolled Keywords:
?? chevkinite-(ce) phenocrystsfluorite andgold flat tuffmagma mixingnevadaperalkaline rhyolitestopic:ash flowfluoritemagmamagmatismperalkaline rockphenocrystrhyoliteunited statesgeochemistry and petrology ??
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25 Mar 2019 14:35
Last Modified:
16 Dec 2023 01:30