摘要
变质沉积岩普遍含有碳质物,其源自沉积母岩中有机质。在变质过程中这些有机质逐渐转变为碳质物或石墨,且碳质物结晶程度可以作为变质等级的可靠指示标志。拉曼光谱是表征碳质物结晶度的有效工具,Beyssac et al.(2002a)基于碳质物拉曼光谱参数(R1=D1/G,D1和G为碳质物拉曼光谱峰强;R2=D1/(G+D1+D2),G、D1和D2为碳质物拉曼光谱峰面积)与寄主岩变质温度之间的线性关系构建了碳质物拉曼光谱温度计:T(℃)=-445(R2)+641,其简单且实用,并被应用到阿尔卑斯和喜马拉雅造山带热结构与折返机制研究中;随后,Rahl et al.(2005)对该变质温度计进行修订,修订后温度估算表达式为:T(℃)=737.3+320.9R1-1067R2-80.638R12,并将变质温度估算范围扩展为100~700℃。本文对碳质物拉曼光谱变质温度计的基本原理、方法、应用条件及其在造山带热结构重建与演化方面的研究进展进行了综述,并对碳质物拉曼光谱温度计与传统温度计估算的变质温度进行了系统的对比分析,结果表明碳质物拉曼光谱温度计代表峰期变质温度,不会受后期退变质影响,当传统温度计结果代表峰期变质温度时,二者计算结果一致。碳质物拉曼光谱温度计已被用于造山带热结构重建、折返过程的热演化,以及高应变带、流体相关热异常等研究。尽管变质过程的压力、变质持续时间、碳质物前体类型等因素对于碳质物拉曼光谱温度计的影响尚待研究,但与传统矿物组合温压计相结合,该方法可以有效评价峰期变质条件和造山多期热演化。
Metasedimentary rocks commonly contain carbonaceous materials which derived from the evolution of organic matter originally in the host sedimentary rock.During metamorphic processes,this organic matter is progressively transformed into graphite or the carbonaceous materials with various degrees of crystallization,which is known as a reliable indicator of metamorphic grade.Raman spectroscopy is an effective tool in describing the degree of crystallization of carbonaceous materials.A linear relationship between metamorphism temperature and the Raman spectra parameters(R1=D1/G,where G and D1 are carbon material Raman spectroscopy peak intensities;R2=D1/(G+D1+D2),where G,D1 and D2 are carbon material Raman spectroscopy peak aeras)was firstly established by Beyssac et al.(2002a),namely T(℃)=-445(R2)+641.It is simple and practical and applied to study the thermal structure and exhumation mechanism of the Alps as well as Himalayan orogenic belts.Subsequently,Rahl et al.(2005)further refined the thermometer which is T(℃)=737.3+320.9R1-1067R2-80.638R12,and extended metamorphic temperature calculation range from 100℃ to 700℃.This paper reviews the basic principles,methods and application conditions of carbon material Raman spectroscopy metamorphic thermometer,summarizes their application in study of reconstruction and evolution of orogenic belt thermal structure.A systematic comparative analysis of metamorphic temperature estimated by the carbonaceous Raman spectroscopy thermometer and the traditional thermometer show that the carbonaceous Raman thermometer represents the peak metamorphic temperature and will not be affected by the late retrograde metamorphism and the results of two thermometers are consistent when traditional thermometer represents peak metamorphic temperature.Carbon material Raman spectroscopy metamorphic thermometers have been used in reconstructing thermal structures of the orogenic belt,revealing the thermal evolution of the exhumation process,and studying on thermal anomalies related to high strain zones and fluids.Although the effects of pressure,duration time of metamorphism,carbonaceous material precursor types and other factors on carbon material Raman spectroscopy thermometers need further study in the future,combined with the conventional thermometer,the peak metamorphic temperature ranges calculated by the carbon material Raman spectroscopy metamorphic thermometers in the orogenic belts can reveal the multi-stage metamorphism evolution during orogenic process.
作者
黄保有
张波
张进江
谭舟
张磊
陈思雨
李晓蓉
HUANG BaoYou;ZHANG Bo;ZHANG JinJiang;TAN Zhou;ZHANG Lei;CHEN SiYu;LI XiaoRong(MOE Key Laboratory of Orogenic Belts and Crustal Evolution,School of Earth and Space Sciences,Peking University,Beijing 100871,China;State Key Laboratatory of Lithoshperic Eovlution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China)
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第2期526-540,共15页
Acta Petrologica Sinica
基金
国家自然科学基金项目(41772207)
国家重点研发计划项目(2016YFC0600303)联合资助
关键词
碳质物
拉曼光谱温度计
峰期变质温度
热演化
变质带
造山带
Carbon material
Raman spectroscopy thermometer
Peak metamorphic temperature
Thermal evolution
Metamorphic belt
Orogenic belt
