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Oxygen-Isotope-Based Modeling of the Hydrothermal Fluid Processes of the Taochong Skarn Iron Deposit, Anhui Province, China

Authors :
Niannian Li
Chenfang Guo
Zhaonian Zhang
Yi Cao
Yilun Du
Source :
Minerals, Volume 11, Issue 4, Minerals, Vol 11, Iss 375, p 375 (2021)
Publication Year :
2021
Publisher :
Multidisciplinary Digital Publishing Institute, 2021.

Abstract

The Taochong iron deposit is one of the important skarn deposits in the Middle–Lower Yangtze River metallogenic belt, Eastern China. There are two types of ores in the deposit: skarn- and quartz–calcite-type ores. The skarn-type ore, which is composed of hematite (Hm-1), garnet, pyroxene, actinolite, chlorite, quartz (Q-1), and calcite (Cal-1), is crosscut locally by a quartz–calcite-type ore vein. The quartz–calcite-type ore consists mainly of hematite (Hm-2), magnetite, quartz (Q-2 and 3), and calcite (Cal-2). The δ18Owater value (~2.67‰) of the fluids in equilibrium with Hm-1 is similar to the values of the mixtures of magmatic and meteoric fluids. However, the δ18O values of the fluids in equilibrium with Hm-2 are in the range of 7.64–8.54‰, similar to those of magmatic fluids. The δ18O values decrease systematically from the fluids in equilibrium with Hm-2 (7.64‰ to 8.54‰) to the fluids in equilibrium with magnetite, Q-3, and Cal-2 (−0.12‰ to 4.17‰) and the fluids in equilibrium with Cal-3 (−2.17‰ to 0.36‰). These features of oxygen isotopes indicate that two episodes of hydrothermal activity took place in the Taochong deposit, and both episodes began with a magmatic origin and then progressively evolved by mixing with meteoric water. The results of quantitative simulations suggest that the deposition of the skarn-type ores was most likely caused by the mixing of magmatic and meteoric fluids, whilst the deposition of the quartz–calcite-type ores was most likely caused by the boiling of magmatic fluids and the mixtures of magmatic brine and meteoric water.

Details

Language :
English
ISSN :
2075163X
Database :
OpenAIRE
Journal :
Minerals
Accession number :
edsair.doi.dedup.....8020c8c314ddfc40160c7c5a1924bde3
Full Text :
https://doi.org/10.3390/min11040375