高级检索

青城子矿集区杨树金矿区石榴云母片岩地球化学特征及矿床成因

Geochemical characteristics and genesis of garnet-mica schist in Yangshu Gold District,Qingchengzi Ore Concentration Area

  • 摘要: 青城子矿集区是中国重要的铅锌银金矿集区,地处华北地台北缘东段辽吉裂谷内,区内产出多处小型至大型铅锌矿床及金银矿床,而杨树金矿床是典型的金矿床。杨树金矿床的矿体赋存于大石桥组三段四层、五层及其与盖县组底部接触带中,呈层状、似层状产出。对杨树金矿区赋矿围岩石榴云母片岩的地球化学特征进行了研究,结果表明:石榴云母片岩具有富硅、富铝特征,富集大离子亲石元素Rb、K及高场强元素U、Sm、Ce等,亏损Ba、Nb、Sr、P和Ti等元素,轻重稀土元素分异明显,轻稀土元素较重稀土元素富集。通过对样品进行原岩恢复和构造背景判别,结合前人研究成果,认为杨树金矿区赋矿围岩石榴云母片岩原岩为泥岩或砂岩,形成于被动大陆边缘,推测该矿床为变质—岩浆热液叠加型金矿床。

     

    Abstract: Qingchengzi Ore Concentration Area,located in the Liaoji rift valley in the northeast of the North China Platform,is an important area of lead,zinc,silver and gold deposits in China.There are many small to large scale of lead-zinc deposits and gold-silver deposits in the area.Yangshu Gold District is one of the typical representatives of gold deposits.It mainly occurred in the fourth and fifth layer of the third member of Dashiqiao Formation and the their contact zone with the bottom of Gaixian Formation,and the ore bodies are layered and stratoid.In this paper,the geochemical characteristics of the ore-hosting rock garnet-mica schist of Yangshu Gold District are studied,and the results show that the garnet-mica schist has high SiO2 and Al2O3 content,and is enriched in large ion lithophile elements Rb,K and high field strength elements U,Sm,Ce,but depleted in Ba,Nb,Sr,P and Ti,etc.It also displays obvious fractionation of LILEs and HFSEs and the former is more enriched than the latter.According to the original rock and tectonic setting discrimination diagrams,combining the previous research results,the paper further proposes that the garnet-mica schist of Yangshu Gold District is restored to mudstone or sandstone,and was formed in passive continental margin setting.The deposit genesis is inferred to be metamorphism-magmatic fluids superimposed gold deposit.

     

/

返回文章
返回