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渤海湾盆地北部主要包括黄骅坳陷、沧县隆起、冀中坳陷和下辽河坳陷 ,区内奥陶系厚 6 0 0～ 80 0m ,主要由石灰岩和白云岩组成。下奥陶统分为冶里组和亮甲山组 ,中奥陶统分为下马家沟组、上马家沟组和峰峰组 ,上统缺失。其中下马家沟组、上马家沟组和峰峰组又进一步划分为下段和上段。早奥陶世冶里期和亮甲山期 ,本区以局限海环境为主 ,其内散布着一些潮坪和滩。中奥陶世 ,本区岩相古地理面貌变化旋回极为明显 ,下马家沟期早期潮坪广布 ,晚期以局限海为主 ;上马家沟期早期又是潮坪广布 ,晚期以开阔海为主 ;峰峰期早期潮坪广布 ,晚期又以开阔海为主。在奥陶纪 ,本区经历了 4个大的海侵—海退旋回 ,其中上马家沟期晚期是本区乃至整个华北地台的最大海侵期。
The northern Bohai Bay Basin mainly includes the Huanghua Depression, Cangxian uplift, Jizhong Depression and the Lower Liaohe Depression. Ordovician sediments in the area range from 600 to 800 m in thickness, mainly composed of limestone and dolomite. The Lower Ordovician is divided into Yeli Formation and Liangjishan Formation. The Ordovician Formation is divided into Majiagou Formation, Shangjiagou Formation and Fengfeng Formation, and the upper Ordovician is missing. Among them, Majiagou Group, Majiagou Group and Fengfeng Group were further divided into the lower segment and the upper segment. In the early Ordovician period and Liangjishan period, the area was dominated by the confined sea environment with some tidal flats and beaches scattered therein. In the Middle Ordovician, the gyration of the lithofacies palaeogeographic change in this area was very obvious. The early Shajiazhai period had a wide distribution of tidal flat and the later was dominated by confined sea. In the early Shangjiagou period, it was also a tidal flat, Mainly in the early peak of tidal flat, open late in the open sea. In Ordovician, the area underwent four major transgressions - regression, in which the late Jiajiagou period was the largest transgression of this area and even the entire North China platform.