胶北区域变质型晶质石墨矿成矿初探  

Preliminary study on mineralization of metamorphic crystalline graphitite in Jiaobei area

作　　者：孔凡梅 孙彤 李增胜 李旭平 李大鹏 谭凯舰 KONG FanMei;SUN Tong;LI ZengSheng;LI XuPing;LI DaPeng;TAN KaiJian(College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China;Key Laboratory of Gold Mineralization Processes and Resource Utilization Subordinated to the Ministry of Natural Resources,Key Laboratory of Metallogenic Geological Process and Resources Utilization in Shandong Province,Jinan 250013,China;Shandong Institute of Geological Sciences,Jinan 250013,China)

机构地区：[1]山东科技大学地球科学与工程学院,青岛266590 [2]自然资源部金矿成矿过程与资源利用重点实验室,山东省金属矿产成矿地质过程与资源利用重点实验室,济南250013 [3]山东省地质科学研究院,济南250013

出　　处：《岩石学报》2024年第10期3281-3304,共24页Acta Petrologica Sinica

基　　金：自然资源部金矿成矿过程与资源利用重点实验室;山东省金属矿产成矿地质过程与综合利用重点实验室(KFKT202105);国家自然科学基金委山东联合基金重点项目(U1906207)联合资助

摘　　要：本文对胶北地块平度-莱西晶质石墨成矿带内莱西南墅、平度大金埠、平度东石岭石墨矿区及南墅矿区附近的莱西庞格庄、东白石地区的含石墨孔兹岩进行了野外观察、岩相学分析、主量元素与微量元素分析,并进行了原岩恢复和石墨拉曼光谱研究。研究结果表明,五处研究区含石墨孔兹岩原岩均为粘土岩或页岩,其m(m=100×MgO/Al_(2)O_(3))值呈现出海水沉积环境的特征。南墅石墨矿区含石墨孔兹岩形成于岛弧环境,大金埠、东石岭和东白石含石墨孔兹岩来源于活动大陆边缘,庞格庄含石墨孔兹岩具有被动大陆边缘成因特征,它们均是胶-辽-吉造山带不同构造演化阶段的沉积产物。所研究的含石墨孔兹岩中鳞片状石墨结晶程度较好,石墨拉曼光谱特征与麻粒岩相变质条件下形成的石墨一致,岩相学和拉曼光谱研究表明高晶度石墨形成于温度峰期后的熔体冷却阶段。含石墨孔兹岩野外露头和岩石薄片岩相学特征指示深熔作用/混合岩化作用的普遍性,高晶度石墨的形成与高温-超高温的变质作用密切相关,所研究的含晶质石墨孔兹岩记录了片状石墨矿床中一种主要的矿化过程——深熔作用。约1850~1830Ma的变质年龄既代表了胶-辽-吉带区域减压折返引起的深溶作用或混合岩化作用的时间,也是平度-莱西石墨成矿带高晶度石墨结晶成矿的时代。This study involved field observations,petrographic analysis,major and trace element analysis,original rock restoration and graphite Raman spectroscopy on the graphite-bearing khondalite in the Pingdu Dajinbu,Pingdu Dongshiling,Laixi Nanshu mining area,as well as the Laixi Dongbaishi and Panggezhuang where is the adjacent area to the Nanshu,the studied areas are all within the Pingdu-Laixi crystalline graphite-forming belt of the Jiaobei massif.The protoliths of the studied graphite-bearing khondalite are all clay or shale rocks,and they exhibit the characteristics of a marine sedimentary environment.Graphite-bearing khondalite in the Nanshu graphite mining area formed in an island arc environment,whereas,those graphite-bearing khondalite from the Dajinbu,Dongshiling and Dongbaishi formed in the active continental margin,besides,the Pangezhuang graphite-bearing khondalite display geochemical characteristics of passive continental margin.As a result,these graphite-bearing khondalite are all sedimentary products which formed in different tectonic evolution stages of the Jiao-Liao-Ji orogenic belt.The crystallization degree of the flake graphite in graphite-bearing khondalite is high,and the Raman spectrum characteristics of the graphite are in accordance with the graphite formed under metamorphic conditions of the granulite facies rock.The petrographic and Raman spectrum analysises indicate that high-crystallinity graphite should be formed during the melt-cooling stage after the temperature peak stage of the metamorphism.Field outcrops and thin section characteristics of the graphite-bearing khondalite indicate that the universality of anatexis or migmatization,and the crystallization of high crystalline graphite is closely related to high temperature-ultra-high temperature metamorphism,and the studied graphite-bearing khondalite has recorded a kind major mineralization in flake graphite deposits,it is anatexis.The metamorphic age of about 1850~1830Ma not only represents the timing of anatexis or migmatization caus

关 键 词：含石墨麻粒岩 高晶度石墨 深熔作用/混合岩化作用 石墨成矿 

分 类 号：P588.347[天文地球—岩石学] P618.252[天文地球—地质学]