摘要
碳是自然界中常见的一种元素,其以单矿物(如石墨、金刚石)、化合物形式(如碳酸盐、二氧化碳)及生物体中的有机碳等多种形式存在。随着越来越多的深入研究,碳质物或石墨化的作用和地位也引起了广泛的关注。石墨碳质物出现在不同地壳深度的断裂带或俯冲带岩石中,特别是在一些大地震断裂带中富集。在地质变质作用过程中,随着温度的增加,非晶形碳质物转变为晶形有序化的石墨,且其石墨化过程不可逆,因此其拉曼光谱峰可定量记录峰期变质作用温度;同时,在变形过程中,石墨的特殊结构性能和力学属性能有效降低岩石强度,促进塑性变形,在快速滑动面或地震滑动面中,起到固体润滑剂作用,因此,地壳中的石墨物质对于岩石强度弱化和地震断裂滑动及演化过程具有重要意义。石墨碳质物具有低溶解性和低移动性,常作为碳汇稳定存在于深部地壳中,在地质时间尺度上,一旦碳及石墨化共同参与到岩石中,一些主要的地质过程(如俯冲作用、断裂作用、风化侵蚀、生物作用)致使石墨碳质物通过形成和破坏过程富集或释放碳到地球表面(大气圈),将显著地影响碳循环。
Carbon is a common element in nature that exists in various forms,including single minerals(e.g.,graphite and diamond),compounds(e.g.,carbonate and carbon dioxide)and organic carbon in organisms.Graphitized carbonaceous materials often form or appear in the rocks of fault zones or subduction zones at different crustal depths and are especially abundant in some large earthquake fault zones.Previous studies have shown the significant role and status of graphitized carbonaceous materials in rock deformation behavior and geological evolution processes.This reveals that the texture of graphite crystals is sensitive to temperature.In the geological process,the crystalline order of carbonaceous materials,that is,the graphitization process,is irreversible,so that the peak metamorphic temperature can be recorded quantitatively.Graphite crystals also have other special structural and physical mechanical properties.Duringthe deformation process,it can effectively reduce the strength of rock and promote plastic deformation.The graphite material in the crust can weaken the rock strength and cause seismic fault slip,which plays an important role in thesolid lubricant and rheological weakening process of faulting or deformation in the fast-sliding or seismic sliding plane.Graphitic carbonaceous materials have low solubility and low mobility and often exist in the deep crust as carbon sinks.On the geological time scale,once carbon and graphitization participate in the rocks together,some major geological processes,such as subduction,faulting,weathering and erosion,as well as biological processes,can cause graphite carbonaceous materials to enrich or release carbon to the earth's surface(atmosphere)through the formation and destruction process,which will significantly affect the carbon cycle.
作者
曹淑云
周丁奎
Cao Shuyun;Zhou Dingkui(a.State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosicences(Wuhan),Wuhan 430074,China;b.School of Earth Sciences,China University of Geosicences(Wuhan),Wuhan 430074,China)
出处
《地质科技通报》
CAS
CSCD
北大核心
2022年第5期101-111,共11页
Bulletin of Geological Science and Technology
基金
国家自然科学基金面上项目(41972220)
国家自然科学基金优秀青年基金项目(41722207)
国家重点研发计划项目(SQ2017YFSF040030)。
关键词
石墨
碳循环
岩石强度
碳汇
地壳构造变形
深俯冲
石墨拉曼光谱
graphite
carbon cycle
rock strength
carbon sink
crustal deformation
deep subduction
graphite Raman spectrum
