论文部分内容阅读
研究区位于青海南部长江源区,大地构造上属东特提斯构造域,为金沙江结合带与澜沧江结合带间昌都地块的一部分.青海南部二叠系沉积类型复杂,多呈断块(片)状出露,尤其是受火山事件影响的下二叠统.关于下二叠统(乌拉尔统)的对比及地层划分目前仍存在较多争议,认识的不同点主要集中于火山岩的层序归属、地质时代、区域对比等.以实测剖面为基础,系统调查岩石地层的岩性组合、沉积环境等,通过着重于各地层单位(尤其是火山岩系)的生物群研究,重新厘定火山-沉积背景下的岩石地层序列.■类动物群的研究表明诺日巴尕日保组和九十道班组在青海南部地区具穿时性.地层序列的建立表明青海南部早二叠世早期为较稳定的浅灰色中厚层状碳酸盐岩.罗甸期强烈的火山喷发,形成了特殊火山-沉积地貌,对沉积古地理格局形成明显的制约,沉积相变快,可划分为4种沉积类型,形成同期异相的诺日巴尕日保组和尕笛考组.自祥播期之后,主要为一套厚层状生物屑灰岩(九十道班组),在青海南部分布较广,代表火山活动暂时停止后的台地相沉积,罗甸期复杂的古地理格局,至此则构成相对统一的较稳定的浅水碳酸盐岩台地.
The study area is located in the source region of the Yangtze River in the southern part of Qinghai Province and belongs to the Eastern Tethys tectonics and is part of the Changdu massif between the Jinshajiang belt and the Lancang River. The Permian sedimentary types in the southern Qinghai are complex and mostly fault blocks Especially in the Lower Permian influenced by volcanic events.Many controversies still exist about the contrast and stratigraphy of the Lower Permian (Urals), and the differences in understanding mainly focus on the sequence of volcanic rocks Belonged to, geologic time, regional contrast, etc. Based on the measured sections, the lithologic assemblage and sedimentary environment of the lithostratigraphy are systematically investigated and the volcanic-sediment is re-determined through the study of the biota focusing on various strata units (especially volcanic rocks) Background sequence of rock stratigraphy.Studies on fauna indicate that the Noritabaururi and Jiuduandan formations have penetrating time in southern Qinghai.The establishment of stratigraphic sequences indicates that the Early Permian in southern Qinghai is relatively stable Light gray medium-thick bedded carbonate rocks.The intense volcanic eruption of Luodian period formed a special volcano-sedimentary landform, which formed obvious constraints on the sedimentary paleogeographic pattern and the sedimentary facies changed rapidly and could be divided into 4 Sedimentary types, the formation of the same phase out of phase Noritaka Ga Ri Bao and Ga-Di test group since the sowing date, mainly for a thick layer of bioclastic limestone (ninety class team) distribution in southern Qinghai more On behalf of the volcanic activity temporarily stopped after the deposition of the platform, Luodian complicated paleogeographic structure, thus forming a relatively uniform, relatively stable shallow carbonate platform.