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北山地区位于华北板块、塔里木板块和哈萨克斯坦板块交汇带,晚古生代构造演化倍受关注且久有争议,该地区晚古生代地层的研究对探讨大地构造演化具有重要意义。利用同位素定年、沉积相分析、粒度分析和碎屑成分统计分析方法对北山地区早石炭世红柳园组进行研究。在下部火山岩中获得LA-ICP-MS锆石U-Pb年龄为359.9±1.4 Ma,参考区域古生物资料,其形成时代应为早石炭世早期。红柳园组上部碎屑岩中发育大量浊流沉积构造和典型鲍马序列,其中砂岩成熟度较低,并且粒度分析结果显示具有浊流沉积的粒度特征,这些证据共同指示红柳园组为近物源浊流沉积。此外通过碎屑组分统计和Qt-F-L、Qm-F-Lt以及Qp-Lv-Ls图解对沉积构造背景进行了探讨,发现研究区红柳园组物源主要来自火山弧,表明其形成的构造环境应为与岛弧邻近的沉积盆地。
The Beishan area is located in the intersection of the North China plate, the Tarim plate and the Kazakhstan plate. The Late Paleozoic tectonic evolution has drawn much attention and has long been in dispute. The study of Late Paleozoic strata in this area is of great significance to the study of tectonic evolution. The Early Carboniferous Hongliuyuan Formation in the Beishan area was studied by means of isotopic dating, sedimentary facies analysis, particle size analysis and detrital composition statistical analysis. LA-ICP-MS zircon U-Pb ages of 359.9 ± 1.4 Ma were obtained from the lower volcanic rocks, and the paleo-biological data of the reference area should be used. The formation time should be Early Early Carboniferous. A large number of turbidite sedimentary structures and typical Bowman sequences are developed in the upper clastic rocks of the Hongliuyuan Formation, with low maturity of the sandstone and grain size analysis showing the grain size characteristics of turbidity flow deposition. These evidences jointly indicate that the Hongliuyuan Formation is a close object Source turbidity flow deposition. In addition, the sedimentary tectonic setting has been discussed based on the statistics of detritus components and Qt-FL, Qm-F-Lt and Qp-Lv-Ls maps. It is found that the source of the Hongliuyuan Formation in the study area mainly comes from the volcanic arc, The environment should be a sedimentary basin adjacent to the island arc.