| Carbon–oxygen isotopic covariations of calcite from Langdu skarn copper deposit,China: implications for sulfide precipitation |
| |
| 作者姓名： | Tao Ren Xingchun Zhang Runsheng Han Baohong Hou |
| |
| 作者单位： | Faculty of Land and Resource Engineering, Kunming University of Science and Technology;State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Science;Minerals & Energy Division, Primary Industries and Resources SA,GPO Box 1671, Adelaide,SA 95000, Australia |
| |
| 基金项目： | supported by the National Science Foundation of China (NSFC) project (40372049) |
| |
| 摘 要： | The Langdu skarn copper deposit in the Zhongdian area, Yunnan Province, China, has an average Cu grade of 6.49 %. The deposit is related to a porphyry intrusion(*216 Ma), which was emplaced in the Upper Triassic sedimentary rocks of the Tumugou and Qugasi Formations.At the Langdu skarn copper deposit, carbon and oxygen isotope ratios of fresh limestones(d18O = 3.0–5.6 % relative to V-SMOW; d13 C = 24.5–25.7 % relative to PDB)and partly altered limestones(d18O = 27–7.2 to-1.9 %;d13C = 11.8–15.2 %) indicated that the deposit was a typical marine carbonate source. Oxygen and carbon isotope values for calcites formed at different hydrothermal stages are-9.1 to 0.2 and 10.1–16.3 %, respectively. Moreover,the carbon–oxygen isotopic composition of an ore-forming fluid(d18O = 5.0–9.5 %, d13 C =-7.3 to-5.3 %) suggested the presence of magmatic water, which most likely came from the differentiation or melting of a homologous magma chamber. The deposition of Calcite I may arise from metasomatism in an open system with a progressively decreasing temperature.Later, the minerals chalcopyrite, pyrrhotite, quartz and Calcite II were precipitated due to immiscibility. Water–rock interaction could potentially be responsible for Calcite III precipitation in the post-ore stage.
|
| 关 键 词： | Stable isotope á Copper deposit á Skarn á Fluid evolution á Yunnan province |
| 本文献已被 CNKI 等数据库收录！ |
|
