徐州地区震旦系贾园组的风暴沉积

徐州地区震旦系下部的贾园组具有丰富典型的风暴沉积标志，包括各种冲刷－充填构造、丘状交错层理、碎屑流沉积、粒序层理及卷曲层理等。通过详细的野外观测及室内研究，根据风暴沉积标志的组合可划分出6种风暴沉积序列类型。其中，类型Ⅰ为具粒序层理的薄层含粉砂灰岩，形成于风暴浪基面以下的远源风暴浊流的末梢；类型Ⅱ以渠模与丘状交错层理的组合为特征，出现在风暴浪基面与晴天浪基面之间；类型Ⅲ为风暴流成因的碎屑流沉积内碎屑灰岩与底面的冲刷沟槽、丘状交错层理的组合，是形成于晴天浪基面附近的槽道碎屑流型风暴沉积；类型Ⅳ为具颗粒流沉积特征的内碎屑灰岩与冲刷面构造及丘状交错层理的组合，丘状纹层段中常见卷曲层理，形成于滩前陆棚斜坡的上部；类型Ⅴ为夹于湖相薄层灰岩中的鲕粒砾屑灰岩，为风暴水流冲越鲕滩，在滩后湖近滩一侧的风暴沉积；类型Ⅵ为湖相风暴岩，由冲刷面构造、薄层内碎屑灰岩及丘状交错层理的组合，顶部具晴天沉积。各种序列在垂向上叠置，构成向上变浅序列。风暴沉积的研究对于深化区域古地理及地层对比研究具有重要的理论和现实意义。

STORM DEPOSITS IN THE SINIAN JIAYUAN FORMATION OF XUZHOU AREA

There are many depositional characteristics of storm deposits in the Lower Sinian Jiayunn Formation around Xuzhou area, including scouring filling structures, hummocky cross stratifications, storm flow generated intraclastic limestones, graded bedding and convolute bedding. Through detailed field observation and laboratory study, a total of six types of storm deposits have been recognized. Type I is represented by the thin bedded silty micrites formed by distal storm turbidity currents below storm wave base. Type II is characterized by the limestones with gutter cast and HCS, which were deposited at the place between storm and fine weather wave base. Type III consists of intraclastic limestones with the debris flow introclasts, HCS, and scouring base, which was formed in the vicinity of the fair weather wave base. Type IV is characterized by the intraclastic limestones with scouring surface, HCS and convolute bedding, which was formed in the upper ramp environment. Type V is characterized by oolitic rudaceous limestones intercalated within the lagoon facies thin bedded limestones, which was deposited at shoal side of the lagoon. Type VI is represented by lagoon facies storm deposits with scouring surface, thin bedded intraclastic limestones, HCS and fair weather deposits. These types of storm deposits tend to superimpose each other vertically to form an upward shallowing sequence.