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二叠纪罗甸期是青藏高原东特提斯构造域泛裂谷化活动的鼎盛期.由于火山物质的喷发及陆源物质的影响,造就青海南部治多-杂多地区复杂的海底火山-沉积地貌,出现4种沉积类型,呈北西西向展布的以台地相火山岩-灰岩型为中心,围绕其分布的是浅水斜坡相(沉)凝灰岩型,向两侧为岛间洼地相砂泥岩型,最外侧则是深水斜坡相(角)砾屑灰岩型.综合地质填图结果分析,基于研究区主要剖面研究,识别出7种沉积相类型,建立了火山岛沉积相模式.该模式揭示出由于强烈的中基性火山喷发,在昌都地块内部快速而间歇地构建一些呈链状展布的火山岛.在火山活动相对宁静期,火山岛缘发育小型碳酸盐礁、浅滩、台地,深水斜坡、洼地相沉积围绕着火山岛链分布.在火山岛的不同部位出现3种■类生物组合,火山岛之上或其边缘为台地相Misellina-Schwagerina组合,火山岛的侧翼斜坡相中见异地Pseudofusulina-Schwagerina组合,水体较深的火山岛之间产洼地相Parafusulina组合.研究表明,昌都地块内部在泥盆纪至二叠纪初期为较稳定的浅海相沉积建造,自罗甸期开始出现陆壳基底的(火山)岛海相间的古地理格局.在祥播期之后,构成统一的较稳定的浅水碳酸盐台地,显示裂陷盆地活动性明显减弱.孤峰晚期呈现分异,裂谷盆地的不稳定性又有所增加.晚二叠世整个昌都地块进入裂谷闭合回返阶段.
Permian Luodian period is the heyday of the easterly tectonism of the Qinghai-Tibet Plateau, due to the eruption of volcanic material and the influence of terrigenous materials, resulting in the complex submarine volcano-sediment in the Zhiduo-Zaduo area of southern Qinghai Geomorphology, there are four types of sedimentary facies, northwest and west to the distribution of the platform facies volcanic rocks - limestone type center, around it is distributed shallow shale facies (Shen) tuff type, on both sides of the island depression sandstone and mudstone type , And the outermost is the deep-water ramp (horn) gravelly limestone type.According to the result of comprehensive geological mapping, based on the study of the main sections in the study area, seven sedimentary facies types are identified and the volcanic island sedimentary facies model is established. Due to the intense mantle volcanic eruption, some volcanic islands with chain-like distribution are rapidly and intermittently built within the Qamdo massif. During the relative quiet period of volcanic activity, the volcanic island margin developed small carbonate reefs, shallows and platforms , Deepwater slopes and depression facies are distributed around the volcanic island chain. There are three species assemblages in different parts of the volcanic island: the Misellina-Schwagerina assemblage above the volcanic island or at the edge of the volcanic island, See the combination of Pseudofusulina-Schwagerina and Parafusulina in the lower volcanic island of the water body.The study shows that the interior of the Qamdo block is relatively stable during the Devonian to Early Permian, The Paleogeography of the (volcanic) island marine facies started to appear, and after the sowing date, the formation of a unified and stable shallow carbonate platform showed that the activity of the rift basins was obviously weakened. The instability of the rift basin increased again.The entire Changdu massif of the Late Permian entered the stage of the rift closure and return.