Application of Analytical Techniques of Spectroscopy on Cherts in Orogenic Belt and Its Geological Significances
CHEN Shuo1,3,4, SU Zhi-hua2, ZHOU Yong-zhang1,3,4*, YANG Zhi-jun1,3, LI Hong-zhong3,4*, ZHOU Wei-li3,4, ZHANG Yan-long3,4
1. School of Earth Science and Geological Engineering,Sun Yat-sen University,Guangzhou 510275,China
2. School of Resource & Environmental Management,Guizhou University of Finance and Economics,Guiyang 550025,China
3. Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Survey,Guangzhou 510275,China
4. Research Center for Earth Environment & Resources,Sun Yat-sen University,Guangzhou 510275,China
Abstract:The Devonian cherts profile was developed in Lvhe area, Xunyang basin of southern Qinling orogenic belt, and the microfabric features based on spectroscopy characteristics clearly recorded information of diagenesis and later stage evolution of the cherts. Cherts in Lvhe area, Xunyang basin of southern Qinling orogenic belt were taken as object, by means of Raman spectroscopy,Fourier transform infrared spectroscopy and X-ray powder diffraction,and the results of this study showed that:low temperature quartz and a small quantity of carbonate minerals were the two main mineral phases of the cherts, and XRD analysis further proved the carbonate minerals were dolomites. Within the cherts in Lvhe area,Gauss fitting FWHM and Area values of the 463 cm-1 Raman shift of SiO2 texture confirmed that recrystallization had occurred in the SiO2 minerals. Alone with this process, variations of degree of order were triggered by fluid effects as well as the quartz itself. During the recrystallization process of the quartz, degree of order went up. The cherts were altered by later fluids, apart from the intersected late vein, the alteration reflected in that the closer to the edge of the fluids in the quartz, the higher the crystallinity and degree of order. In this study, alteration of cherts made by orogeny mainly reflected in two aspects:on the one hand,tectonic stress destroyed the continuity of the cherts and provides space for migration and intersection of later stage hydrothermal fluids;On the other hand,participation of the late fluids accelerated the recrystallization of quartz. In this study, infrared spectroscopy is capable of identifying mineral structure type systematically, and Raman spectrum analysis can reveal in situ microfabric characteristics, and XRD shows significant advantage in discriminating trace impurity minerals in cherts. These spectroscopy methods provide important demonstrations in studying the diagenetic evolution of the cherts.
陈 铄,苏志华,周永章,杨志军,李红中,周维丽,张彦龙. 谱学分析在造山带硅质岩中的应用及其地质意义[J]. 光谱学与光谱分析, 2019, 39(04): 1128-1135.
CHEN Shuo, SU Zhi-hua, ZHOU Yong-zhang, YANG Zhi-jun, LI Hong-zhong, ZHOU Wei-li, ZHANG Yan-long. Application of Analytical Techniques of Spectroscopy on Cherts in Orogenic Belt and Its Geological Significances. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2019, 39(04): 1128-1135.