摘要
自然界中不同的应力体制、应变速率都可能影响岩石脆-韧性变形的转换温度,而韧性剪切带中糜棱岩的变形变质温度估算对热年代学结果的解释具有重要制约。为了讨论地质温度计(白云母/黑云母Ti地质温度计)在伸展韧性剪切带中的适用性,本文利用糜棱岩的矿物动态重结晶以及EBSD石英轴组构等塑性变形特征,估算出桂东北资源韧性剪切带的变形变质温度在400~550℃之间。结合电子探针分析技术,对韧性剪切过程中由于动态重结晶作用新形成的细粒白云母、黑云母进行化学成分分析,利用白云母/黑云母Ti温度计估算出该韧性剪切带中糜棱岩的变形变质温度分别为409~528℃和458~605℃。通过对比分析,利用地质温度计获得的温度与利用塑性变形特征估算出的温度在误差允许范围内基本一致,为白云母/黑云母Ti温度计在伸展韧性剪切带中的应用提供了依据。
Different stress regimes and strain rates in nature can influence the transition temperature of rocks from brittleness to ductility,estimating the deformation and metamorphism temperatures of mylonite in ductile shear zones is crucial for interpreting thermochronological results.To assess the applicability of geothermometers(biotite/muscovite Ti geothermometers)in ductile shear zones,our study employed mineral dynamic recrystalli-zation of mylonite and plastic deformation features,such as EBSD quartz<c>-axis fabrics,to estimate the de-formation and metamorphism temperatures of Ziyuan ductile shear zones in Northeastern Guangxi,ranging from 400 to 550℃.Through the utilization of electron probe analysis techniques,chemical composition analyses were conducted on newly formed fine-grained biotite and muscovite resulting from dynamic recrystallization dur-ing ductile shearing.By employing biotite/muscovite Ti thermometers,the metamorphic deformation temperature of mylonite in the Ziyuan ductile shear zone were estimated to be between 409-528℃and 458-605℃,re-spectively.Through comparative analysis,the temperatures obtained using geothermometers were essentially consistent within the allowable error range with those estimated using plastic deformation features,providing a basis for the application of biotite/muscovite Ti thermometers in extensional ductile shear zones.
作者
刘锟
李赛赛
辛良伟
石春燕
耿杰利
LIU Kun;LI Saisai;XIN Liangwei;SHI Chunyan;GENG Jieli(Collaborative Innovation Center for Exploration ofNonferrous Metal Deposits and Efficient Utilization ofResources By the Province and Ministry,Guilin University ofTechnology,Guilin,Guangxi 541004,China;College ofEarth Sciences,Guilin University ofTechnology,Guilin,Guangxi 541004,China;College ofTourism and Landscape Architecture,Guilin University ofTechnology,Guilin,Guangxi 541004,China)
出处
《现代地质》
北大核心
2025年第3期774-786,共13页
Geoscience
基金
广西自然科学基金项目(2020JJA150030)
国家自然科学基金项目(42262026)。
关键词
桂东北
韧性剪切带
糜棱岩
地质温度计
变形变质温度
Northeast Guangxi
ductile shear zone
mylonite
geothermometer
metamorphic-deformation tem-perature
作者简介
刘锟,男,硕士研究生,1995年出生,主要从事构造地质学研究工作。Email:1037961211@qq.com;通信作者:李赛赛,男,博士,教授,1983年出生,主要从事构造地质学研究工作。Email:lanqi178@glut.edu.cn。
