| Sediment source analysis is an important part of sedimentary basin analysis.Its research helps to understand the geographical location of the source area,the nature of the parent rock,the distance and path of sediment transport,and analyze and discuss the sedimentary area of the sedimentary area.The relationship between the deposition area and so on.The choice of provenance analysis methods plays an important role in the analysis of sediments.At present,the commonly used source analysis methods include sedimentation method,petrology method,cathodoluminescence method,heavy mineral method,geochemical method,geophysics Methods,clay mineral methods,magnetic mineralogical methods and mineral particles for the morphology of the method.And the source information of the sediments is excavated with the development of the single particle mineral micro-differentiation technology(thermal ionization mass spectrometry,ion probe mass spectrometry,electron probe chemistry and ion mass spectrometry).Accuracy is getting higher and higher,the measured source information is more accurate and reliable.In particular,the heavy mineral method(debris zircon U-Pb dating)and cathodoluminescence method are widely used in the study of sediments of the Yangtze River and the evolution of the water system.Based on the source analysis of debris zircon in Quaternary river sediments of four typical sections(Level 5 Terrain T-TL01 Sample,Modern river bed sediments,Plane PT-01 and PT-02)of Chongqing-Zigui section of Yangtze River,Observation of zircon cathode cathodic characteristics and U-Pb age characteristics(Th / U ratio characteristics,U-Pb harmonic curve characteristics and U-Pb age pattern characteristics),To determine the sedimentary matter source area,and then to explore the evolution of sediments in the study area and the impact on the evolution of water system.The Yangtze River when the formation of the Three Gorges and other time through the Yangtze River water system evolution has been the concern of scholars at home and abroad,so more accurate limits the formation of the Yangtze River has become a hot topic of today's research.The Yangtze River is one of the longest rivers in the world.It originated in the Qinghai-Tibet Plateau.Its formation and evolution are closely related to the change of geomorphology in China.The changes of landforms cause the river system to change,thus affecting the river sediment change.In this paper,the geology chronology method(zircon U-Pb dating)and cathodoluminescence are used to study the debris zircons of the Quaternary sediments in the Chongqing-Zigui section of the Yangtze River.The following conclusions are obtained:(1)the modern river floodplain sediments magma zircon increased,there are 40.8Ma of the ancient zircons of zircon imports,160-480 Ma zircon zircon mainly magma,from the Emeishan basaltic characteristics of zircon.(2)the Yangtze River in Chongqing-Zigui section of the formation occurred in the T5 terraces before the formation of cloud dream period after the formation of the plane,so through the time between 0.7Ma early Pleistocene.(3)The combination of cathodic luminescence and heavy mineral single-particle micro-partitioning zirconium;stone U-Pb dating technique provides an efficient means for accurately predicting the location and precision dating of the parent rock source area,so that the source analysis is more accurate and efficient The... |
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