摘要
为探讨贵州织金含稀土磷矿床的形成时间和成矿物源,利用Sm-Nd同位素稀释法对该矿床磷块岩中6个小壳化石及胶磷矿样品进行了年龄测定.样品的质谱分析测试结果显示,样品的147Sm/144Nd与143Nd/144Nd构成了一条相关性良好的线性等时线;计算结果表明织金含稀土磷矿床具有533±22Ma的Sm-Nd等时年龄,εNd(t)值为-2.44~-2.77,表明它们具有相同的成因和相近的形成时代,本次测得年龄代表着真实的成矿年龄;二阶段Nd的模式年龄为1313~1338Ma.结合前人对该矿床稀土元素地球化学的研究成果表明,织金含稀土磷矿床的成矿物源有新生地幔物质组分的加入.
In order to discuss the age and the provenance of the Zhijin REE-bearing phosphorites in Guizhou, six small shell fossils and cellophane sampled from the phosphorites are dated by Sm-Nd isotopic dilution method. The results of mass spectrographic analysis show that the value of ^147Sin/^144Nd and ^143 Nd/^144 Nd formed an isochronal line. The test shows that the Sm-Nd isochronal dating of Zhijin REE-bearing phosphorites is 533±22 Ma (MSWD= 1.1 ). The εNd(t) of the samples are about -2.44 to -2.77, and the Nd two-stage model ages (T2DM) are 1 313-1 338 Ma. This result suggests that the samples have the same genesis and the approximative age, and the age represents the true mineralogenetic epoch. Combined with the REE geochemistry the juvenile mantle is responsible to the provenance of the Zhijin REE-bearing phosphorites.
出处
《地球科学(中国地质大学学报)》
EI
CAS
CSCD
北大核心
2008年第2期205-209,共5页
Earth Science-Journal of China University of Geosciences
基金
中国科学院知识创新工程重要方向项目(NoKZCX3-SW-125)
浙江林学院科学研究发展基金项目(No2351000584)