相山火山盆地打鼓顶期火山机构研究
发布时间：2018-12-20 11:46
【摘要】：江西相山火山盆地燕山期中期火山活动频繁,按岩浆活动序次可分为打鼓顶期和鹅湖岭期两个亚旋回。早期岩浆活动形成的打鼓顶组火山岩主要出露于盆地的西北缘,由于受晚期岩浆活动破坏、火山岩的覆盖,打鼓顶期的火山活动特征、火山机构的分布至今没有统一认识。因此作者在前人研究的基础上,依托“相山火山盆地三维地质调查”项目,选取相山火山盆地早白垩世打鼓顶期岩浆活动作为主要研究对象。通过野外地质调查收集了大量的流纹英安岩样品及照片并大量测量熔岩中捕虏体产状;打鼓顶组火山-沉积岩的地球化学特征、岩性岩相时空展布以及X岩石组构图等数据进行研究,结合已有钻孔资料分析,推测打鼓顶期古火山口、火山通道等火山机构的分布,并参照前人遥感解译的结果,对火山机构进行论证。根据室内外综合研究推断相山火山盆地打鼓顶组的火山口位置,进而分析其喷发类型及形成的地质构造环境,为相山火山盆地地质演化研究提供素材。研究表明,打鼓顶组不同岩性及岩相的时空展布对火山机构及喷发模式有着重要的研究意义。①打鼓顶组火山熔岩(流纹英安岩)岩层厚度及底板高度受地势及受重力影响,结合其产状,推测早期岩浆流动,从而反演火山通道位置;打鼓顶组火山碎屑岩中火山集块岩对火山通道有着重要的指示意义,火山角砾岩中的角砾随熔岩流动造成捕掳体沿着某一特定方向排列,其长轴方向指示岩浆的流动方向。通过打鼓顶组火山-沉积岩特征推测的火山口位置与相对应的遥感解译的火山口位置基本一致。这些特征说明利用岩性组合、岩石产状及捕虏体产状特征来指示火山口的大致位置是可行的。②利用内打鼓顶组火山碎屑岩和熔岩岩层厚度数据,可以计算火山爆发指数,同时结合不同位置的岩相组合,确认相山火山盆地内打鼓顶期火山活动强度,结合火山爆发指数推测火山通道位置。最终得出结论相山火山盆地打鼓顶期岩浆活动主要受相山火山盆地基底的EW向隐伏断裂控制。区域内火山整体爆发指数较低,火山活动较为平静,盆地中部断裂带附近存在1个中心式喷发的主火山口,盆地北部存在5个火山喷发点底部次级断裂相通形成复合式火山机构,形成了大量环状、放射状构造。盆地东侧、东南及南部地区均存在岩浆沿盆地打鼓顶早期火山活动产生的的环状断裂上侵形成岩墙,打鼓顶组火山—沉积岩环绕盆地边缘零星出露。
[Abstract]:There are frequent volcanic activities in the middle Yanshanian period in Xiangshan volcanic basin, Jiangxi Province. According to the order of magmatic activity, they can be divided into two subcycles: the Dagu top stage and the E Hu Ling period. The volcanic rocks of the Daguding formation formed by the early magmatic activities are mainly exposed to the northwestern margin of the basin. Due to the destruction of the late magmatic activities, the coverage of the volcanic rocks and the characteristics of the volcanic activities during the tamping period, the distribution of the volcanic bodies has not been uniformly recognized up to now. On the basis of previous studies, the author chooses the early Cretaceous thumping magmatic activity as the main research object based on the project of "Three-dimensional Geological Survey of Xiangshan Volcano Basin". Through the field geological survey, a large number of samples and photographs of streamline andesite were collected, and the occurrence of xenoliths in molten rock was measured. The geochemical characteristics of volcanic-sedimentary rocks in the Daguding formation, the temporal and spatial distribution of lithologic lithofacies and the composition of X rock formation are studied. The distribution of volcanic mechanisms such as the ancient crater and the volcanic channel in the Dagutingding period is inferred through the analysis of the existing drilling data. According to the results of remote sensing interpretation, the volcanic mechanism is demonstrated. The location of the crater of the Dagudding formation in Xiangshan volcanic basin is inferred according to the indoor and outdoor comprehensive studies, and the eruption type and geological tectonic environment are analyzed, which provides the material for the study of geological evolution of Xiangshan volcanic basin. The results show that the temporal and spatial distribution of different lithology and lithofacies of the Daguting formation is of great significance to the volcanic mechanism and the eruption model. 1 the thickness and the floor height of the volcanic lava (rhyolite andesite) of the Dagutingding formation are affected by the topography and gravity. According to its occurrence, the early magma flow can be inferred, and the location of volcanic channel can be retrieved. The volcanic aggregates in the clastic rocks of the Daguding formation play an important role in indicating the volcanic passageway. The breccia in the volcanic breccia is arranged along a certain direction with the flow of lava, and its long axis indicates the direction of magma flowing. The location of crater inferred from the characteristics of volcanic-sedimentary rocks of the Daguding formation is basically the same as that of the corresponding remote sensing interpretation of the crater. These characteristics indicate that it is feasible to use lithologic assemblage, rock occurrence and xenoliths to indicate the general location of the crater. 2 using the thickness data of volcanic clastic rock and lava strata of the Neda Dudding formation, the volcanic eruption index can be calculated. Combined with the lithofacies assemblage of different positions, the intensity of volcanic activity in the top stage and the location of the volcanic channel in the Xiangshan volcanic basin were confirmed and the volcanic eruption index was used to estimate the location of the volcanic channel. Finally, it is concluded that the magmatic activity in the topping stage of the Xiangshan volcanic basin is mainly controlled by the EW concealed faults in the basement of the Xiangshan volcanic basin. The whole volcanic eruption index in the region is relatively low, and the volcanic activity is relatively calm. There is a central eruption of the main crater near the central fault zone in the middle of the basin. In the northern part of the basin, there are five secondary faults at the bottom of the eruption point to form a composite volcanic mechanism, forming a large number of annular and radial structures. On the eastern, southeast and southern sides of the basin, magma transgressions along the annular faults caused by the early volcanic activities at the dagumping stage of the basin, and the volcanic-sedimentary rocks of the Daguting formation emerge sporadically around the margin of the basin.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P317
本文编号：2387952
[Abstract]:There are frequent volcanic activities in the middle Yanshanian period in Xiangshan volcanic basin, Jiangxi Province. According to the order of magmatic activity, they can be divided into two subcycles: the Dagu top stage and the E Hu Ling period. The volcanic rocks of the Daguding formation formed by the early magmatic activities are mainly exposed to the northwestern margin of the basin. Due to the destruction of the late magmatic activities, the coverage of the volcanic rocks and the characteristics of the volcanic activities during the tamping period, the distribution of the volcanic bodies has not been uniformly recognized up to now. On the basis of previous studies, the author chooses the early Cretaceous thumping magmatic activity as the main research object based on the project of "Three-dimensional Geological Survey of Xiangshan Volcano Basin". Through the field geological survey, a large number of samples and photographs of streamline andesite were collected, and the occurrence of xenoliths in molten rock was measured. The geochemical characteristics of volcanic-sedimentary rocks in the Daguding formation, the temporal and spatial distribution of lithologic lithofacies and the composition of X rock formation are studied. The distribution of volcanic mechanisms such as the ancient crater and the volcanic channel in the Dagutingding period is inferred through the analysis of the existing drilling data. According to the results of remote sensing interpretation, the volcanic mechanism is demonstrated. The location of the crater of the Dagudding formation in Xiangshan volcanic basin is inferred according to the indoor and outdoor comprehensive studies, and the eruption type and geological tectonic environment are analyzed, which provides the material for the study of geological evolution of Xiangshan volcanic basin. The results show that the temporal and spatial distribution of different lithology and lithofacies of the Daguting formation is of great significance to the volcanic mechanism and the eruption model. 1 the thickness and the floor height of the volcanic lava (rhyolite andesite) of the Dagutingding formation are affected by the topography and gravity. According to its occurrence, the early magma flow can be inferred, and the location of volcanic channel can be retrieved. The volcanic aggregates in the clastic rocks of the Daguding formation play an important role in indicating the volcanic passageway. The breccia in the volcanic breccia is arranged along a certain direction with the flow of lava, and its long axis indicates the direction of magma flowing. The location of crater inferred from the characteristics of volcanic-sedimentary rocks of the Daguding formation is basically the same as that of the corresponding remote sensing interpretation of the crater. These characteristics indicate that it is feasible to use lithologic assemblage, rock occurrence and xenoliths to indicate the general location of the crater. 2 using the thickness data of volcanic clastic rock and lava strata of the Neda Dudding formation, the volcanic eruption index can be calculated. Combined with the lithofacies assemblage of different positions, the intensity of volcanic activity in the top stage and the location of the volcanic channel in the Xiangshan volcanic basin were confirmed and the volcanic eruption index was used to estimate the location of the volcanic channel. Finally, it is concluded that the magmatic activity in the topping stage of the Xiangshan volcanic basin is mainly controlled by the EW concealed faults in the basement of the Xiangshan volcanic basin. The whole volcanic eruption index in the region is relatively low, and the volcanic activity is relatively calm. There is a central eruption of the main crater near the central fault zone in the middle of the basin. In the northern part of the basin, there are five secondary faults at the bottom of the eruption point to form a composite volcanic mechanism, forming a large number of annular and radial structures. On the eastern, southeast and southern sides of the basin, magma transgressions along the annular faults caused by the early volcanic activities at the dagumping stage of the basin, and the volcanic-sedimentary rocks of the Daguting formation emerge sporadically around the margin of the basin.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P317
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