摘要
本文利用Ｒｂ－Ｓｒ等时线方法测得第一阶段似斑状黑云母花岗岩、第二阶段等粒黑云母花岗岩和第三阶段花岗斑岩的成岩年龄分别为（１５２±９）×１０￣６ａ、（１３７±７）×１０￣６ａ～（１３６±６）×１０￣６ａ和（１３１±１）×１０￣６ａ。Ｓｒ－Ｎｄ同位素资料表明各阶段花岗质岩石均基本上源于地壳物质的重熔。与钨多金属矿化有关的似斑状黑云母花岗岩和等粒黑云母花岗岩属同一岩浆体系分异演化的产物，其钕模式年龄（ｔ＿（ＤＭ）＝２３０７×１０￣６ａ）反映出成岩物质来自早元古宙地层的重熔。与铅－锌－银矿化有关的花岗斑岩的钕模式年龄（ｔ＿（ＤＭ）＝１２８４×１０￣６～１５７８×１０￣６ａ）示意出其成岩物质来自中元古宙地层的重熔。
The Qianlishan granite stock is genetically associated with the world-famous Shizhuyuansupergiant polymetallic tungsten deposit. Being a composite stock,it consists of a pseudopor-phyritic biotite granite body with an area of 5. 9 km￣2,an equigranular biotite granite bodywith an area of 4. 1km￣2,and granite porphyry dikes.Radiometric dating with Rb-Sr whole rock isochron method was successfully applied tothe measurement of various stages of granites in the Qianlishan granite stock,yielding the da-ta (152±9)×10￣6 a for pseudoporphyritic biotite granite,(137±7) × 10￣6 a for central phase ofthe equigranular biotite granite body,(136±6) ×10￣6 a for marginal phase of the equigranularbiotite granite body,and(131±1) ±10￣6 a for granite porphyry dikes.Initial ε_(Nd)and ε_(Sr) values are calculated to be 6. 39 to 7. 59 and 43. 1 to 107. 7 forpseudoporphyritic biotite granite, 4. 52 to 7. 53 and 73. 4 to 506. 2 for equigranular bio-tite granite, and 5. 17 to 8. 64 and 176. 6 to l79. 1 for granite porphyry. Initial87_(Sr)/86_(Sr)values of pseudoporphyritic biotite granite, equigranular biotite granite, and granite por-phyry are 0. 7088,0. 7187～0. 7215 , and0. 71 68 respectively.These data indicate that all ofthe granitoid rocks dre derived from the crust. Neodymiurm model ages(t_(DM))range from1949×10￣6 a to 2632×10￣6 a with a mean of 2307×10￣6 a for pseudoporphyritic biotite granite,and 1284 × 10￣6 a to 1578 × 10￣6 a for granite porphyry. As equigranular biotite granite wasformed through the differentiation of pseudoporphyritic biotite granite magma,there is noreasonable single-stage evolutional model ages for it.The model ages,to some extent,sug-gest that pseudoporphyritic biotite granite and,possibly, equigranular biotite granite areremelting products of the Lower Proterozoic strata which are generally considered to be thematerial source of tin and tungsten granites in South China, and the granite porphyry is de-rived from the Middle Proterozoic strata.Derived from different sources, different granitoid rocks in Shizhuyuan area show re-markable difference in preferentiality for metallogenic elements,i.e,pseudoporphyriticbiotite granite and equigranular biotite granite are associated with W-Sn-Mo-Bi-Be minerali-zations ,whereas granite porphyry is related to Pb-Zn-Ag mineralizations.
出处
《矿床地质》
CAS
CSCD
北大核心
1995年第3期235-242,共8页
Mineral Deposits
基金
地质行业基金资助项目─-"柿竹园钨多金属矿床成矿作用"研究成果
关键词
锶
钕
同位素
花岗岩
钨矿床
Rb-Sr whole-rock isochron, Nd-Sr isotopes, granite, polymetallic tungstendeposit,Shizhuyan
