| The formation and evolution of Jinsha - Yalong - Anning river system was a production of the long-term geological background that the Indian plate moved to the northward (east), Tibetan Plateau rase, the southeast edge of the plateau out to the southeast, adjacent to the geological mutual adjustment, and the Chinese landscape pattern from west to east Continue to strengthen. The Late Cenozoic Xigeda deposition thickness, lithology typical of a high degree of accumulation of more than 70 years of research. There had been lots of research results In its lithological characteristics, distribution, age and other basic question, however, little in-depth Exploration of before Xigeda deposition - the deposition process - eroded the ancient geography of the formation and evolution. This article based on the direct record of Xigeda, prepare to reserch the the formation and evolution process of before Xigeda deposition - the deposition process - eroded the ancient geography, that the conversion of the ancient Jinsha River - Yalong River - Anning Riverâ†'ancient Lake Xigedaâ†'Jinsha - Yalong - Anning River. It has great Significance of confirming if there had been a unified Xigeda ancient lake in late Cenozoic. After the formation of the ancient Lake Xigeda, the source came from the nearby islands of the lake which was above the surface of the water, therefore, It formed in different places with different non-metallic deposits. To analyse the nonmetallic ore and the position of mineralizing, has great meaning of searching for the non-metallic in Panzhihua and Panxi Area.It could be comfirmed that the Landscape before the formation of the ancient Lake Xigeda,according to the strata of the occurrence, distribution and lithological characteristics of the Pre-Cenozoic and the relationship between the Xigeda and it.Thus, it illustrated that all the big deformation, fracture, fold was formed before the Xigeda deposition. Comparing with the present landscape, it had no great variation from the formation of ancient Lake Xigeda to the Xigeda deposition.It could be comfirmed that the Panzhihua region was lacustrine deposits according to the attitude, distribution, horizontal bedding and clastic sedimentary structure of the Xigeda layer. It was level deposition from 1600m to 900m above the river bottom around. It was formed by a uniform deposition of Xigeda Lake, not because of the raise or lower by the tectonic movement, and Now scattered formed due to erosion.In the Panzhihua region, Xigeda widely distributed. To research the erosion mechanism Xigeda by the distribution and occurrence characteristics. This article analyzes to reserch the the process of formation and erosion of the ancient Lake Xigeda and the conversion mechanism of ancient Jinsha River - Yalong River - Anning Riverâ†'ancient Lake Xigedaâ†'Jinsha - Yalong - Anning River. Thus, by studying Xigeda horizontal and vertical changes in lithology, provenance differences in changes in geochemical characteristics of correlation analysis to examine Xigeda Panzhihua mineralization, and provide basis for prospecting.In the progress of the geological events in the long history, Panxi area has experienced the process of convertion that ancient Jinsha Riverâ†'ancient Lake Xigedaâ†'Jinsha River.It formed the Jinsha River - Yalong - peace river system, and deposited a thicker Xigeda stratum. It is distributed in the Anning River, Yalong, the Jinsha River valley and tributaries on both sides of the low-lying mountain valleys or open areas, not integrated in the different age strata above the more obvious lateral changes of lithology, source with diversity. Xigeda ancient lake source is not very far away from the river by long-distance transport sediment from different locations, but the nearby islands of the lake above the water surface from such erosion. The deposition of sedimentary environment and topography of Xigeda was similar to the present, thus, due to the different regions of the material Xigeda different sources and depositional environments, different clastic sediments was formed, can be used as a non-metallic minerals. According to this principle, to comparing the lithology, chemical composition, the correlation analysis of the Xigeda stratum thoughtout Panzhihua and the source area rock, made following points: in Miyi, which the source is Late Permian Emeishan basalt and granite, was easy to formed diatomite; in Hemenkou and Tongde, which the source is he Sinian dolomite and Palit complex, was easy to foemed brick clay; and in Hongge, it was easy to formed kaolin mine . Based on the above understanding, easy-to-Formation in Xigeda find related minerals. For example: to search the diatomite in the wide, clean waters deposition area; to search kaolin source in the area of granite place ; to search brick clay common in the source area of sedimentary rock complex area.It is the first time to proposed the formation of the Xigeda Lake was related to the differential movement of the boundary faults of the Sichuan-Yunnan Block which is surrouding by the Fault Zone Xianshui River, and the Fault Zone Anning River-Zemu River-Xiaojiang River,and Fault Zone Ailao Mountain, and Fault Zone Jinsha River. The first application of three-dimensional satellite photos and geological maps reflect the regional geological content (distribution of Xigeda) simulation of the ancient lake Xichang area Xigeda look, summed up the basis of local geographical source of ancient Lake District rocks, Stratum prospecting point of view. |
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