Fluid Inclusion and H, O, S, and Pb Isotope Studies on Beilou Porphyry Copper Deposit in Zouping County, Shandong Province, China
详细信息
- 责任者：Wang Hao (State Key Laboratory for Mineral Deposit Research ; School of Earth Scinces and Engineering ; Nanjing University ; Nanjing 210093 ; China) ; Xu Zhaowen
- 刊名：Acta Mineralogica Sinica
- 出版年：2013
- 卷期：33(1)
- 页码：p.83-91
- issnNo：ISSN1000-4734
- isbnNo：CN52-1045/P
摘要
On the basis of field geological investigation,the authors discuss the genesis of Beilou copper deposit with the methods of fluid geochemistry and isotopic geochemistry.The homogenization temperature of primary fluid inclusions,in the mineralized quartz veins of Beilou copper deposit,ranges from 158 ℃ to 385 ℃ with an average of 270 ℃,while their salinity ranges from 2.74% to 62.51% NaCl with an average value of 15.2% NaCl.Peak homogenization temperatures are 210-240℃ and 270-300℃,with the peak salinity of 5%-10% and 55%﹣ 60% NaCl,respectively.Ore-forming fluid boiling occurred at 250℃ to 380℃,resulting the formation of three-phase fluid of liquid-rich and gaseous-rich fluid at medium-high temperature and low salinity,containing daughter minerals with medium-high temperature and high salinity.At 250℃,the high salinity three-phase fluid disappeared,and ore-forming fluid changed into liquid-rich fluid at medium-low temperature and low salinity.Raman analysis of the fluid inclusions indicates that,in the gaseous phase,water vapor is dominant with small amount of CO2.The δ18OH2O and δD values of quartz range from 1.26‰ to 7.24‰(average value being 4.63‰) and from-89‰ to-69‰(average value being-76.67‰),respectively,implicating that the ore-forming fluids are mainly derived from magma and mixed with meteoric water.Values of δ34S in pyrite and chalcopyrite range from-2.8‰ to-1.3‰(average value being-1.75‰) and from 1.02‰ to 2.12‰(average value being 1.46‰),respectively.Values of206Pb/204Pb range from 18.295 to 18.402 with an average of 18.349;207Pb/204Pb from 15.555 to 15.573 with an average of 15.564;208Pb/204Pb from 38.215 to 38.331 with an average of 38.273.This indicates that sulfur and lead are originated from lower crust or mantle and are influenced by the mixture of the upper crust rocks and meteoric water in the late ore-forming stage.This research confirms that this Beilou copper deposit is a shallow medium-high temperature porphyritic copper deposit.