1. Oxygen-Isotope-Based Modeling of the Hydrothermal Fluid Processes of the Taochong Skarn Iron Deposit, Anhui Province, China
- Author
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Niannian Li, Chenfang Guo, Zhaonian Zhang, Yi Cao, and Yilun Du
- Subjects
lcsh:QE351-399.2 ,010504 meteorology & atmospheric sciences ,Geochemistry ,Skarn ,Pyroxene ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,Isotopes of oxygen ,chemistry.chemical_compound ,Actinolite ,iron-rich skarn deposit ,Middle–Lower Yangtze Valley ,oxygen isotope ,Chlorite ,0105 earth and related environmental sciences ,Calcite ,lcsh:Mineralogy ,quantitative simulation ,Geology ,Geotechnical Engineering and Engineering Geology ,chemistry ,Meteoric water ,engineering ,Vein (geology) - 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. more...
- Published
- 2021
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