Nanoparticles Study on the Indosinian Xiaomei Shear Zone in the Hainan Island,China:Implication to Developmental Stage and Formation Mechanism of Nanoparticles in a Fault Zone  

作　　者：Yang Zhou Baoyun Shen Yi Yan Hailing Liu Yan Yan 

机构地区：[1]Key Laboratory of Ocean and Marginal Sea Geology,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Guangdong University of Technology,Guangzhou 510006,China [4]South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou 510301,China

出　　处：《Journal of Earth Science》2020年第5期957-967,共11页地球科学学刊（英文版）

基　　金：the National Natural Science Foundation of China(Nos.41776072,41676048,U1701641,91328205)。

摘　　要：Nanoparticles are widely observed in the natural shear zone and experimental slip faults, which can lubricate the fault and significantly reduce the friction coefficient during seismic slip. But it is still not clear how the nanoparticles develop during the process of sliding. Clarifying the development stage of nanoparticles in a fault zone is critical to understanding the formation mechanisms of nanoparticles and the mechanism of fault weakening from a nanoperspective. In this study, four types of nanoparticles were found in the Indosinian Xiaomei shear zone, including spherical nanoparticles, rod-like nanograins and their aggregations. Ultramicroscopic analyses indicate that polished patches are highly smooth and composed of tightly packed spherical nanoparticles and well orientated rod-like nanograins during slip at high velocities. Meanwhile, the dome nanoparticles were formed by the calcite thermal decomposition due to frictional heat during highspeed sliding. The polygonal grooves are possibly related to high temperature(>900℃) grain boundary sliding deformation mechanisms. However, the porous and rough surfaces are accompanied by a series of holes and parallel "scratches" during a subsequent low-velocity stage. To ascertain the chemical composition of these nanoparticles, the energy dispersive spectrometer(EDS) test were conducted. The results suggest that materials rich in Fe, MgO and wollastonite are likely to form the rod-like nanograins, while materials rich in SiO2 are likely to form the spherical nanoparticles.

关 键 词：NANOPARTICLES slip faults development stage Xiaomei shear zone composition 

分 类 号：P738.4[天文地球—海洋地质]