摘要
沉积物通常含有不同程度的有机质,在其埋藏—成岩和后期变质作用过程中,随着温度的升高,沉积母岩中的有机质由无序状态向碳质逐渐转变,最终转化为有序结晶的石墨。碳质物的结构有序度(结晶程度)与变质作用的温度条件直接相关。激光拉曼光谱能够表征碳质物分子内部的振动模式,反映碳质物结晶程度,进而揭示其变质程度和温度条件。激光拉曼光谱碳质地温计(RSCM)是基于已知变质温度的样品,通过获取分析其中碳质物的激光拉曼光谱特征,总结出其谱峰位置、峰高、峰面积、半峰全宽等参数与变质温度之间存在的良好相关性,从而定量地估算未知样品在区域变质和接触变质作用过程中所经历的峰期变质温度。RSCM方法通过与其它传统的地质温度计进行比对研究,证实可行有效,并具有准确高效、原位无损、量程范围大、对结构敏感、应用范围广、不受退变质干扰等优点,对恢复区域构造热演化、地壳热状态等具有重要的意义。文章回顾了碳质物激光拉曼光谱地温计的研究历史,介绍了谱带分布理论及其随温度的变化规律,梳理了近年来该方法的研究进展,概括了其在地学不同研究领域中的应用,并对其研究前景进行了展望。
Organic matter is usually enriched in sediments,and will be transformed from disordered carbonaceous material to fully-ordered crystalline graphite,after being buried and heated to some high temperature during metamorphism.The crystalline order is closely corresponding to the certain temperature condition of metamorphism.The Raman spectroscopy(RS)can reflect the vibrational modes of molecules of carbonaceous material(CM),and to reveal the crystalline degrees of graphite,and thus the metamorphic conditions.The RSCM method is an empirical geothermometer by obtaining and analyzing the Raman parameters like band position,peak intensity,band area and FWHM(full width at half maximum)of carbon or graphite grains from a series of metamorphic samples,whose metamorphic temperatures are already known or can be calculated by other methods.A close correlation between the RSCM and peak metamorphic temperature is very well defined,so as to quantitively calculate the peak temperature of the unknown samples during regional or contact metamorphism.Based on the comparisons with the traditional geothermometers,it is suggested that the RSCM is practicable and reliable,and it shows several advantages such as high efficiency,in situ and nondestructive measurements,wide range of temperature detection,high sensitivity to CM inner structures,being free from later retrograde metamorphism,and wide fields of application.Thus,this method is significant for the reconstruction of regional tectonic and thermal evolution,and crustal thermal state.This paper reviews the study history of the RSCM,introduces the theory on CM Raman spectrum band distribution and its relationship with metamorphic temperature,summarizes some representative studies of natural graphitic carbons by Raman spectroscopy in recent years,and its applications in different fields of Earth Sciences.The research foreground of RSCM is finally prospected.
作者
陈一逸
王博
刘珈硕
路升华
COCHELIN Bryan
CHEN Yiyi;WANG Bo;LIU Jiashuo;LU Shenghua;COCHELIN Bryan(State Key Laboratory for Mineral Deposits Research,School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China)
出处
《高校地质学报》
CAS
CSCD
北大核心
2023年第6期908-923,共16页
Geological Journal of China Universities
基金
国家自然科学基金(41772225)
国家自然科学基金国际(地区)合作与交流项目(42011530146)
国家自然科学基金外国青年基金(42050410312)联合资助。
