碳酸盐台地演化过程中有一种比较常见的沉积现象,即浅滩化,并通常认为其连续性较差.本文报道了最近在四川盆地中三叠统雷口坡组新发现的一种罕见的碳酸盐台地“巨型浅滩化(mega-shoaling)”现象.研究区于中三叠世雷口坡期在干旱炎热的气候条件下发育了受限的陆表海型碳酸盐台地,其中的雷-1-1亚段B层沉积了一套几乎遍及全盆地的滩相颗粒岩,形成所谓的巨型(盆地规模)浅滩化特征.根据岩芯精细描述和薄片镜下鉴定,发现这套滩相颗粒岩以砂屑云岩(灰岩)为主,其次为鲕粒云岩(灰岩),以发育局限泻湖-台内滩、局限泻湖-台内滩-台坪和潮坪-潮缘滩这3种向上变粗、变浅的沉积序列为特征;多旋回小层划分与对比研究发现,这套滩相颗粒岩在横向上具有良好的可追踪对比性和等时性;基于岩芯刻度测井方法建立的测井相模板,对全盆地235口井进行了逐井解释,发现滩相颗粒岩的累计厚度一般在10～40 m,连续分布面积超过1.5×105 km2,这充分说明了当时的碳酸盐台地确实在较短时间内发生了巨型浅滩化作用.重点从古构造与古地貌、古气候、海平面相对升降变化和古水动力等成滩条件角度分析了这种巨型浅滩化的成因,认为多种地质因素的有机结合为巨型浅滩化创造了有利的地形条件,包括平静的古构造环境、相对平坦的古地貌和蒸发岩的填平补齐作用;在稳定沉降的碳酸盐台地上,具有快速海侵到缓慢海退的多旋回高频海平面升降变化,这既有利于颗粒滩在垂向上的多旋回连续叠加发育,也有利于颗粒滩的横向迁移、连片和叠置,从而形成大面积连续分布的巨型颗粒滩沉积,形成巨型浅滩化.对这种碳酸盐台地具有现今盆地尺度的巨型浅滩化研究,有助于丰富完善对碳酸盐台地滩相沉积的认识,还因滩相沉积通常发育优质油气储层,所以还具有重要的储层地质学意义. One of the more common sedimentary phenomena in the evolution of carbonate platforms is shoal shoal, which is generally considered to be less continuous.This paper reports a new rare discovery recently found in the Middle Triassic Leikoupo Formation in the Sichuan Basin Carbonate platform “mega-shoaling” phenomenon in the study area in the Middle Triassic Leikou period in arid climate conditions under the development of a limited land surface sea carbonate platform, of which A series of beach-facies granulites, almost all of the basin, have been deposited in layer B of mine-1-1 Subbundle to form a so-called mega (basin-scale) shoal characteristic. According to the detailed description of the core and microscopic identification of the flake, Phase granulites are dominated by dolomite dolomite (limestone), followed by oolite dolomite (limestone), with the development of confined lagoons - inland beaches, confined lagoons - Taiwan inland beaches - Tai Ping and tidal flat - tidal flats The three types of sedimentary facies, which are thicker and shallower, are characterized by sedimentary facies. The study on the division and contrast of the polycyclic small layers shows that this beach facies granulite has good traceability and isochronism in the horizontal direction. Logging facies templates built by scale logging method were well-interpreted from 235 wells in the entire basin and found that The accumulated thickness of facies granites generally ranges from 10 m to 40 m, and the continuous distribution area exceeds 1.5 × 10 5 km 2, which fully shows that the carbonate platform at that time did indeed have a giant shoal shoal effect in a relatively short period of time. Paleo-geomorphology, paleoclimate, relative sea-level change and palaeo-hydrodynamic, etc., the causes of this giant shoals are analyzed. It is concluded that the organic combination of multiple geological factors creates favorable topographic conditions for giant shoals, including Calm paleo-tectonic environment, relatively flat paleogeomorphology and evaporite fill up; in the stable settlement of the carbonate platform with rapid transgression to slow sea multi cyclone high frequency sea level changes in elevation, both Which is beneficial to the continuous superimposition and development of multiple cycles in the vertical direction of the particle beach. It is also conducive to the lateral migration, contiguous and stacking of the particle beach so as to form a large-area continuous distribution of giant particle beach deposits and form a giant shallow shoal. The study of the Jurassic shallow shoal of the present basin scale in the Yantai area is conducive to enriching the understanding of the facies sediments of the carbonate platform and also to the development of high-quality oil and gas reserves , So it has important significance reservoir geology.