Geochemical Characteristics of Intermediate-acid Hypabyssal Intrusions and Dykes in Danghenanshan Area of South Qilian and Its Implications on the Gold Mineralization(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2016年第06期
- Page:
- 753-765
- Research Field:
- 基础地质与矿产地质
- Publishing date:
Info
- Title:
- Geochemical Characteristics of Intermediate-acid Hypabyssal Intrusions and Dykes in Danghenanshan Area of South Qilian and Its Implications on the Gold Mineralization
- Author(s):
- DAI Shuang; LIU Bo; YAN Ning-yun; ZHANG Xiang; JIN Zhi-peng; MENG Zhen; YANG Huai-yu; WU Zhi-jiang; BAI Bin; ZHANG Li-li; PENG Dong-xiang
- 1. College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu, China; 2. Key Laboratory of Western China’s Environmental Systems of Ministry of Education, Lanzhou University, Lanzhou 730000, Gansu, China; 3. Gansu Institute of Geological Survey, Lanzhou 730000, Gansu, China; 4. No.2 Institute of Geological and Mineral Exploration of Gansu, Lanzhou 730030, Gansu, China
- Keywords:
- hypabyssal intrusion; dyke; geochemistry; petrogenesis; tectonic setting; Au deposit; Paleozoic; Qilian Mountain
- PACS:
- P588
- DOI:
- -
- Abstract:
- The Late Caledonian small intermediate-acid hypabyssal intrusions and dykes in Danghenanshan area of South Qilian include granite and granite porphyry, subrhyolite porphyry, subdacite porphyry, quartz diorite and quartz diorite porphyrite. The mass fractions of SiO2 are 53.05%-74.12%, and the sums of mass fractions of K2O and Na2O are 4.01%-10.43%. The rock series include calc-alkaline, high-potassium calc-alkaline, shoshonite and alkaline with the characteristics of peraluminous-quasi-aluminous, and the high-potassium calc-alkaline and alkaline series are main. The rocks have the characteristics of low contents of rare earth elements, and are relatively enriched in light rare earth elements, large ion lithophile elements (Rb, Ba, La, Ce and Sr), Th and U, and relatively depleted in high field-strength elements (Nb, Ta, Zr and Hf) and heavy rare earth elements with weak-mediate negative Eu anomaly (0.7-0.9). The occurrence characteristics of intermediate-acid intrusions and dykes and the analysis results of trace elements show that the rocks form in post-collisional tectonic setting, and the source rocks of magma are mainly metabasite and a little of metasedimentary, so that the rocks maybe inherit the geochemical characteristics of source rocks. There is metasomatism between magma and wall rock in the process of emplacement. The magmatic differentiation is ranked by granite and granite porphyry, subrhyolite porphyry, subdacite porphyry, quartz diorite and quartz diorite porphyrite in the ascending order. The Au content of rock from dyke is low, and that of meta-acid rock increases because of the alteration. The intermediate rock of dyke (quartz diorite) provides thermal source and provenance for gold mineralization in Langchagou and Dongdonggou mining areas.
Last Update: 2016-12-01