论文部分内容阅读
通过右江盆地二叠纪生物礁层序地层研究表明 ,在海平面升降旋回的各个时期 ,均有生物礁的发育 ,并呈现各自特征的层序内部构型及成因格架。低水位礁仅发育于台盆背景 ,以加积丘礁或点礁为特色 ,常与混屑浊积岩、硅灰岩、硅泥岩共生 ;陆棚边缘礁发育于台盆和斜坡背景 ,与低水位期的相比 ,礁体较大 ,数量较多 ,因为该期相对稳定的底质和水动力条件对生物礁的萌生更具诱导作用 ;海侵期表现为伴随海平面向陆超覆而形成的向陆年轻化的海侵型台盆礁、斜坡礁、台缘礁、台内礁组合 ,具加积 -退积型堆积序列 ,礁顶发育硬底、生物挠动面、海底熔蚀面、淹没面、水下中止面等 ,礁盖包括硅岩、火山碎屑浊积岩、放射虫岩、骨针岩、深水遗迹相、生物密集层、浮游相灰岩、含锰磷酸盐灰泥岩等 ,生长方式主要是追补式和中止式 ,以宝塔礁、链状礁、点礁为主 ;高水位礁以进积礁、加积礁和混积礁组合为特征 ,广泛发育于台内、台缘、斜坡、台盆等环境 ,具向上变浅序列 ,礁顶发育暴露面、岩溶面、冲刷侵蚀面、钙化壳、白云岩帽等 ,礁盖主要有残积相、潮坪相、浊积相、丘滩相等 ,规模大、分布广 ,以堤礁、环礁、马蹄形礁为主。
Through the study of Permian reef sequence stratigraphy in the Youjiang Basin, it is shown that there are reefs in all stages of sea level rise and descent cycle, and the sequence internal structure and genesis framework of each sequence are presented. Low-water-level reefs are only developed in the background of the basin and are characterized by the Jijiuqiu reef or the reef. They are often co-exuded with turbidite, silica-limestone and siltstone. The marginal reef of the shelf is developed in the background of the basin and the slope, Compared with the low water level period, the reefs are larger and larger in number, because the relatively stable sediment and hydrodynamic conditions during this period are more inducing to the reef aeration. The transgression period appears as the sea surface overrides The reef-type sedimentary reefs, ramp reefs, marginal reefs, and inland reef assemblages formed by the rejuvenation of the inland continents are characterized by sedimentary-sedimentary accumulation sequence, hard bottom development at the reef top, bio-flexural surface, seafloor erosion Surface, submerged surface and underwater suspended surface. The reef covers include siliceous rock, volcaniclastic turbidite, radiolarian rock, rock needle rock, deep water relics facies, bio-dense layer, planktonic limestone, manganese-containing phosphate ash Mudstone and so on. The main growth modes are the reclamation type and suspension type, with pagoda reefs, chain reefs and point reefs as their main features. The high water reefs are characterized by progressive reefs, plus reefs and mixed reefs and are widely developed in Taiwan , Taiwan edge, slope, basin and other environments, with a shallow up sequence, reef top development exposed surface, karst surface Erosion surface erosion, calcified shell, dolomite caps, the cap main reef residual phase, tidal flat, turbidite, equal mound Beach, scale, widely distributed to barrier reef, atoll, based horseshoe reef.