摘要
利用Sm-Nd同位素法测试了海南岛土外山金矿区花岗-绿岩系的15个样品,7个为绿岩中的斜长角闪片岩,8个为花岗(质)岩,分别获得了1700.9±20Ma和1379.7±17Ma的Sm-Nd等时年龄,各自代表了其原岩的成岩时代。同时对花岗(质)岩获得了与1700.9013220Ma相当的1690~1800Ma的Nd模式年龄。对斜长角门片岩则获得2300~2700Ma的Nd模式年龄。这些反映了海南岛于2400Ma、1700Ma、1400Ma左右发生了三次重大构造岩浆热事件。
The protolith age of the metamorphic rock in Hainan Island has never been solved for a long time. Fifteen samples including seven samples of anorthose-diastatite schist and eight samples of Hainan Island are taken to be measured by Sm-Nd radioactive isotope method in this study. Two isochron ages of 1700. 9+20 Ma and 1379. 7+17 Ma have been obtained, respectively. These ages are respectively interprered as the time of the Protolith-formation.Meanwhile granitic roock has got a Nd model age of 1691~1792 Ma which corresponds to 1700. 9+ 20 Ma, and also anorthose-diastatite-schist has obtained a Nd modelage of 2316~2689 Ma.These renflect that three important tectono-magma thermal enents took place at 2400 Ma, 1700Ma and 1400 Ma in Hainan Isiand. These events played an important role for the gold-ore formation in Precambrian granitic-greenstone belt of Hainan Island.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
1995年第1期71-76,共6页
Acta Petrologica Sinica
基金
中国科学院"五七"黄金重点项目
关键词
花岗岩
绿岩系
钐
钕
同位素年龄
地质意义
Granitic-greenstone series
Sm-Nd age
Tuwaishan of Hainan Island