Study On Volcanic Apparatus Of The Daguding Group In Xiangshan Volcanic Basin

There had been a great active volcano in mid-yanshan cycle in Xiangshan, Jiangxi Province. The action of volcano has been divided into two cycles, namely Daguding and Ehuling basis on the time and feather of magmatic activities. The volcano rock of Daguding formation formed in the early cycle of volcano action mainly crop out in the northwestern margin of the basin. The feature of the volcano active and distribution of the volcanic edifice of the Daguding cycle have not had an unified understanding by far because it had been damaged by late lava activate and covered by the upper volcano rock of Ehuling formation.Therefore the author basis of previous studies, based on the project of "The 3D geological survey Xiangshan volcano basin", selecting Daguding magmatic activities of the Xianshan volcano basin as the main object of study in early Cretaceous. A large number of rhyolitic samples and photographs has been collected by the geological survey in the field, measurements the xenolith tends in lavas, the geochemistry tincture of Daguding formation volcano-sedimentary rock, the lithology and lithofacies distribution, rock group analysis of X ray diffraction and so on, and based on the interpretation of remote sensing and analysis of existing drilling data, the distribution of ancient crater and volcanic channels of the volcanic edifice of the Daguding cycle. At last referring to the results of previous remote sensing interpretation, argument for the Volcanic edifice. According to the comprehensive research of inside and outside of the room from Xiangshan volcano basin Daguding formation volcano eruption, and then analyzes its eruption type and formation of geological tectonic environment,This study provides materials for the research on the evolution of Xiangshan volcanic basin.Studies have shown that Daguding formation set of different lithology and lithofacies of the space-time distribution and eruption of the volcano mechanism model has important research significance.①The Daguding formation lava(rhyolitic) strata thickness and bottom highly affected by the terrain andunder the influence of gravity, combined with its occurrence, speculated that early lava flow, thereby inversion volcano channels position. The volcanic agglomerate of Daguding formation in the volcanic clastic rock for volcano channels has important instruction significance. The breccia in volcanic breccia with lava flow capture body arranged along a specific direction, he instructions lava flows along the long axis direction. Through a Daguding formation volcanic- sedimentary features that the crater position and corresponding remote sensing crater position are basically identical. These characteristics shows that using the lithologic combination, the attitude of rock and xenolith occurrence characteristics to indicate the approximate location of the crater is feasible.②Using the Daguding formation volcanic clastic rock and lava rock thickness data, volcanic eruption index can be calculated, at the same time, t the same time, combined with the lithofacies combination in different position, confirmed that the volcanic activity of Daguding cycle in volcanic basin. Finally,combined with volcanic eruptions index speculation volcano channels position.The final conclusion Daguding cycle magmatic activities of Xiangshan volcano basin is mainly controlled by the concealed fault which tend EW of volcanic basin basement. The volcano index is lower overall thw area, volcanic activity is relatively calm, basin near the central fault zone is 1 central major volcanic eruption, northern basin exist 5 volcanic eruption points at the bottom of the second-order faults are interlinked to form composite volcanic mechanism, formed a large number of circular structure and radial structure. Basin in the east, southeast and south regions have magma along the basin volcanism of early Daguding encroached to become rock wall formation by the circular structure. The volcanic-sedimentary of Daguding exposed scattered around the edge of Xiangshan volcanic basin...