现代地质2024，Vol.38Issue(4)：922-933,12.DOI:10.19657/j.geoscience.1000-8527.2024.093
镁铁质岩浆周期性补给对云南普朗斑岩Cu-Au矿床的制约:能量约束下热力学模拟
Constraints from Periodic Replenishment of Mafic Magma on Porphyry Mineralization in the Pulang Porphyry Cu-Au Deposit,Yunnan Province:Energy-constrained Thermodynamic Modeling
摘要
Abstract
Periodic replenishment of mafic magma into silicic magma chambers is a critical factor in the forma-tion of large-scale porphyry deposits.Using the Pulang giant porphyry copper-gold deposit as an example,this study aims to quantitatively assess the significance of the formation of process porphyry deposits by constructing an energy-constrained thermodynamic model.Mafic microgranular enclaves(MMEs)are widely developed in both the pre-ore coarse-grained quartz diorite porphyry(CQD)and the syn-ore quartz monzonite porphyry(QMP)in the Pulang deposit.Petrological characteristics with rhythmic zoning and resorption textures of amphi-bole and biotite,and the presence of elongated apatife,both indicate the replenishment of mafic magma.Com-pared to the fractional crystallization model(FC),the multi-stage replenishment-fractional model(R3FC)indi-cates that the replenishment of mafic magma would suppress the crystallization of feldspar,and promote the for-mation of multiple types of amphiboles and significantly advance the crystallization time of magmatic biotite.Using the correlation between the molar fraction variations of siliceous magma materials and volatiles as a refer-ence,the results indicate that the replenishment of mafic magma would increase the H2 O content of the residual melt in the early stages and decrease it in the late stage of magma evolution(0.16％,0.04％,and-0.30％).It will continuously increase the SCSS(sulfur concentration at sulfide saturation in silicate melt;78.74 × 10-6,94.44 × 10-6 and 137.88 × 10-6),and Cl solubility(0.04％,0.10％and 0.20％),but the effect on Cu solubility is limited.The results indicated that the R3FC and FC models under the energy-con-strained system can not only explain the petrological characteristics of the Pulang porphyry intrusions but also quantitatively verify the contribution of mafic magma replenishment to the abnormally high H2O,S,and Cl con-tents in the ore-forming rocks.关键词
岩浆混合/热力学模拟/挥发分/普朗斑岩Cu-Au矿床Key words
magma mixing/thermodynamic modeling/volatile/Pulang porphyry Cu-Au deposit分类
天文与地球科学引用本文复制引用
张少颖,和文言,肖仪武..镁铁质岩浆周期性补给对云南普朗斑岩Cu-Au矿床的制约:能量约束下热力学模拟[J].现代地质,2024,38(4):922-933,12.基金项目
国家自然科学基金项目(42302082,42372098) （42302082,42372098）
国家重点研发计划项目(2022YFF0800902) （2022YFF0800902）
高等学校学科创新引智计划(BP0719021) （BP0719021）
中国地质大学地质过程与矿产资源国家重点实验室专项基金(MSFGPMR201804)和深时数字地球前沿科学中心"深时数字地球"中央高校科技领军人才团队项目(2652023001). （MSFGPMR201804）
