摘要
中奥陶世克里摩里期,鄂尔多斯西部地区为镶边陆架的碳酸盐岩台地,自东向西依次发育开阔台地、台地边缘浅滩、台缘斜坡—斜坡脚、广海陆棚和深水海槽相带,从浅水区经由碎屑流搬运来的块状钙质角砾岩在台缘斜坡—斜坡脚相带集中堆积,形成厚度不等的透镜体夹于正常深水灰泥石灰岩和泥岩中。乌拉力克期发生较大规模构造运动,盆地东部整体抬升,西部边缘发生裂陷,沉积范围以同生正断层为界,随着海平面的上升沉积环境演变为相对闭塞的深水斜坡—盆地,沉积一套富含笔石的泥页岩地层,并不时有陆源克里摩里组垮塌的石灰岩沉积物被带入盆地,形成数量不等的多套角砾岩夹层。
During the Middle Ordovician Kelimoli Age, a rimmed carbonate platform occurred in western Ordos area, with open marine platform, platform-margin shoal, slope, toe-of-slope, deep shelf and deep trough facies orderly distributed from east to west. Massive calcareous breccias packages in thin or thick lenticular shapes derived by debris-flow from east shallow water facies, accumulated along slope to toe-of-slope, and surrounded by in-site deep water micrite and mudstone. Strong tectonic movement hap- pened during the Wulalike Age, faulting in the western margin and uplifting in the whole eastern 0rdos Basin. Sediments restricted by border syn-sedimentary faults. As sea level rising, sedimentary setting changed to relative restricted deep slope-basin. Rocks of the Wulalike Formation are mainly composed of abundant graptolite bearing mudstone and shale, intercalated with several calcareous breccias which trans- ported by debris flow from the early collapsed Kelimoli Formation limestone in the east uplift land.
出处
《古地理学报》
CAS
CSCD
北大核心
2013年第6期751-764,共14页
Journal of Palaeogeography：Chinese Edition
基金
国家科技重大专项(编号:2011ZX05004-006)资助
关键词
鄂尔多斯西部
钙质角砾岩
碎屑流
岩相古地理
western Ordos area, calcareous breccias, debris flow, lithofacies palaeogeography
