摘要
高黎贡变质带位于高黎贡走滑剪切带以西，呈NS向或NEsw向带状展布，是滇西最显著的带状变质带之一，其热演化史和变形时限不清晰。本文选取变质带内花岗质糜棱岩、花岗质片麻岩及其斜长角闪岩包体和云母片岩为研究对象，利用40Ar／39Ar和KAr法地质测年，获得40Ar／39Ar年龄结果为33．7～10．18Ma，KAr年龄结果主要集中在1O～13Ma和16．7～22．8Ma。据野外地质产状和显微结构特征，研究认为高黎贡山变质岩的变形时限为35Ma之后。综合研究区内40Ar／39Ar年代学和裂变径迹年龄结果，变质带热演化史显示高黎贡变质带在24Ma伴随部分基性岩浆侵位并隆升，古温度降低至350～300℃，12～10Ma变质带继续隆升冷却至300～220℃，此后经历缓慢冷却过程，约5．5Ma降至120～60℃，热年代学年龄数值结果显示从南向北隆升幅度差异。
The NS or NE-SW trending Gaoligong metamorphic belt lying in western Yunnan Province is distributed along west Gaoligong strike-slip shear zone. Its thermal evolutional history and deformed ages has been an issue of little consensue. This study conducted 40Ar/39Ar dating by using Laser 40Ar/39Ar VG5400 and conventional 40Ar/39Ar dating system for granitic mylonite, granitic gneiss, amphibolite xenolith and mica schist from the Gaoligong metamorphic and deformational zone. The 40Ar/39Ar dating results range from 33. 7-10. 18Ma, and K-Ar ages concentrate about 10-13Ma and 16. 7-22. 8Ma. Based on field geologic features and the characteristics of the microstructure, the metamorphic rocks deformation of Gaoligong metamorphic belts began after -35Ma. Combined with 40Ar/39Ar chronologic result and fission track data in the study area, the thermal evolution history of the metamorphic belt shows that the paleogeothermal temperature of the Gaoligong belt was down to 300-350℃ at 24Ma accompanied by partial mafic magma emplacement and uplifting, and continued to cool down 220-300℃ at 10-12Ma, and had a slow cooling process before down to 60 - 120℃ at 5. 5Ma. The thermochronology ages may indicate the uplift amplitude difference from south to north.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2013年第12期1887-1900,共14页
Acta Geologica Sinica
基金
国家自然科学基金项目(编号40872149
40930419)
中央级科研院所基本科研资助专项(编号K1309)联合资助的成果
关键词
变质和变形作用
热史演化
40Ar
39Ar年代学
高黎贡变质带
滇西
metamorphism and deformation
Gaoligong metamorphic belt
West Yunnan thermal history revolution
40Ar／39Ar chronology
作者简介
王丹丹，女，1982年生。工程师，矿产普查与勘探专业。Email：ddwangcn@163．com
通讯作者：李宝龙，男，助理研究员。Email：xinzhongguolong@163．com。
