河北地质大学学报2026，Vol.49Issue(4)：22-35,14.DOI:10.13937/j.cnki.hbdzdxxb.2026.04.003
滇东南个旧碱性岩的成岩演化与不相容元素富集特征
Diagenetic Evolution and Enrichment Characteristics of Incompatible Elements of Gejiu Alkaline Rocks in Southeastern Yunnan
摘要
Abstract
The Gejiu complex rock body develops a complete suite of magmatic rocks ranging from mafic to alkaline.Previous studies have primarily focused on acidic granites related to tin mineralization,with less attention paid to alkaline rocks.Recent discoveries of good enrichment in Th,U,and rare earth elements in alkaline rocks from Changlinggang and Baiyunshan,but their evolution and enrichment processes remain unclear.This paper conducts research on the two rock bodies through field investigations,petrographic and geochemical analyses.The results indicate that the Gejiu alkaline rocks belong to the potassium basalt series,characterized by high Al2O3(13.63％～21.80％),high total alkalis(7.76％～16.72％),low MgO,MnO,and P2O5;they strongly enrich Th(115× 10-6～249 × 10-6),U(26× 10-6～50× 10-6),and REEs(∑ REE=699× 10-6～803 × 10-6),with a right-skewed REE distribution pattern.Zircon U-Pb dating shows they formed during the Late Yanshanian period(82～80 Ma).Comprehensive studies suggest that the rocks exhibit characteristics of a mantle source enriched by subduction fluids,having undergone varying degrees of partial melting and fractional crystallization,with the Changlinggang rock body showing lower degree of melting.The intraplate tectonic environment provided the thermal source for the magmatic crystallization differentiation of the Gejiu alkaline rocks.During crystallization differentiation,the alkaline rocks enriched in Th,U,Nb,and heavy REEs,with highly radioactive enriched biotite veins(Th and U reaching 5 000 × 10-6 and 350 × 10-6,respectively)developed within the rock body,indicating late hydrothermal superimposed enrichment and demonstrating good potential for Th,U,Nb,and REE mineralization.关键词
岩浆演化/元素富集/碱性岩/个旧杂岩体Key words
magma evolution/element enrichment/alkaline rock/Gejiu complex分类
天文与地球科学引用本文复制引用
成飞,晏中海,徐争启,张苏恒,黄迪,冯琪威,宁鹏,张宗博,姚建,张元涛..滇东南个旧碱性岩的成岩演化与不相容元素富集特征[J].河北地质大学学报,2026,49(4):22-35,14.基金项目
中国核工业地质局项目(AH2024-0551) （AH2024-0551）
四川省自然科学基金面上项目(2024NSFSC0090) （2024NSFSC0090）
