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The origin and evolution of skarn-forming fluids from the Phu Lon deposit, northern Loei Fold Belt, Thailand: Evidence from fluid inclusion and sulfur isotope studies

Citation

Kamvong, T and Zaw, K, The origin and evolution of skarn-forming fluids from the Phu Lon deposit, northern Loei Fold Belt, Thailand: Evidence from fluid inclusion and sulfur isotope studies, Journal of Asian Earth Sciences, 34, (5) pp. 624-633. ISSN 1367-9120 (2009) [Refereed Article]

DOI: doi:10.1016/j.seaes.2008.09.004

Abstract

The Phu Lon skarn Cu-Au deposit is located in the northern Loei Fold Belt (LFB), Thailand. it is hosted by Devonian volcano-sedimentary sequences intercalated with limestone and marble units, intruded by diorite and quartz monzonite porphyries. Phu Lon is a calcic skarn with both endoskarn and exoskarn facies. In both skarn facies, andradite and diopside comprise the main prograde skarn minerals, whereas epidote, chlorite, tremolite, actinolite and calcite are the principal retrograde skarn minerals. Four types of fluid inclusions in garnet were distinguished: (1) liquid-rich inclusions; (2) daughter mineral-bearing inclusions; (3) salt-saturated inclusions; and (4) vapor-rich inclusions. Epidote contains only one type of fluid inclusion: liquid-rich inclusions. Fluid inclusions associated with garnet (prograde skarn stage) display high homogenization temperatures and moderate salinities (421.6-468.5 degrees C; 17.4-23.1 wt% NaCl equiv.). By contrast, fluid inclusions associated with epidote (retrograde skarn stage) record lower homogenization temperatures and salinities (350.9-399.8 degrees C; 0.5-8 wt% NaCl equiv.). These data suggest a possible mixing of saline magmatic fluids with external. dilute fluid sources (e.g., meteoric fluids), as the system cooled. Some fluid inclusions in garnet contain hematite daughters, suggesting an oxidizing magmatic environment. Sulfur isotope determinations on sulfide minerals from both the prograde and retrograde stages show a uniform and narrow range of delta S-34 values (-2.6 to -1.1% delta S-34), suggesting that the ore-forming fluid contained sulfur of orthomagmatic origin. Overall, the Phu Lon deposit is interpreted as an oxidized Cu-Au skarn based on the mineralogy and fluid inclusion characteristics.

Item Details

Item Type:Refereed Article
Keywords:skarn, Loei fold belt, Thailand, oxidised skarn
Research Division:Earth Sciences
Research Group:Geology
Research Field:Ore Deposit Petrology
Objective Division:Mineral Resources (excl. Energy Resources)
Objective Group:Mineral Exploration
Objective Field:Copper Ore Exploration
Author:Kamvong, T (Mr Teera Kamvong)
Author:Zaw, K (Professor Khin Zaw)
ID Code:62078
Year Published:2009
Web of Science® Times Cited:30
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2010-03-09
Last Modified:2010-04-15
Downloads:0

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