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大约在十八亿年前左右,在经过长期风化剥蚀后基本上处于准平原状态的华北地台上,沿着北东向的几条基底断裂,形成一个沿朝阳、蓟县、石家庄、长治一线展布的北东向长形断陷沉积盆地。初期,可能仅在局部地区(如蓟县附近)沉积河流相砂砾岩。接着发生广泛的海侵,并且向西侵进到宣化一带,使这里成为一个向东开口的、呈东西向延伸的大海湾,接受了一套近200米厚的以碎屑为主的潮汐沉积物,它们不整合地覆于太古代桑
About 1.8 billion years ago, after a long period of weathering and erosion basically in the quasi-plains of the North China platform, along the north-east several basal rupture, forming a along the Chaoyang, Jixian, Shijiazhuang, Changzhi show North-east long cloth fault basin deposition. Initially, fluvial facies conglomerates may be deposited only in localized areas (such as near Jixian). The widespread transgression followed by a westward invasion into the area of Xuanhua, making it an east-westwardly extended large bay that received nearly 200 meters of detritus-dominated tidal sediments They unconformity over the Archaean mulberry