Abstract:
The Chang 6 interval of the Upper Triassic Yangchang Formation in the Ordos Basin is one of the most important interval of the Mesozoic section.The Chang 6 interval are characterized by the development of reservoir sandbodies and multiple genetic types.During the sedimentary evolution of the Chang 6 interval of Yanchang Formation in Huachi-Qingyang area of the Ordos Basin，liquefaction deformation structures related with palaeoearthquake are developed extensively.The authors，based on many previous research results，by detailed description and observation of drilling cores of Chang 6 interval in the research area，studied the characteristics of liquefaction deformation structures systematicly.The structures mainly include: Load and sand ball structure，vibrational liquefaction curl deformation structure，sand invasion mushroom，liquefaction dike，such as liquefied swing structure.The difference of deformation structures formed by seismic events and gravity slumping are distinguished，mainly as: The advantage deformation direction of deformation structures，the existence of the sliding surface and the existence of uniform layer. Based on the above analyses，the vertical relationship between the delta front sandbody formed by normal deposition or slump turbidite sandbody and seismite sandbody are also studied which include two types: The overlay between seismic events sandbody and the normal deposition sandbody(delta front sandbody); the seismic events sandbody and slump turbidite sandbody formed from delta front.At the end，the origin models are established.
Key words:
Ordos Basin,
Chang 6 interval,
liquefaction deformation structure,
origin of deformation structure,
superimposed relationship between sandbodies,
origin mode
摘要： 鄂尔多斯盆地上三叠统延长组长6 油层组是盆地内中生界最重要的含油层段之一。长6油层组以储集砂体发育、成因类型多样为特征。其中，位于湖盆中部的华池—庆阳地区在长6油层组沉积演化过程中广泛发育了一套与古地震事件有关的液化变形构造砂体。该地区长6油层组砂体中所发育的液化变形构造类型主要包括：负荷及砂球构造、振动液化卷曲变形构造、沙侵蘑菇、液化岩脉、液化摆动构造等。地震事件与重力滑塌所形成的变形构造的区别主要表现在：变形构造的优势方位、是否存在滑动面和是否存在均一化层。与古地震事件有关的液化变形构造砂体和其他成因类型砂体的叠置，主要包括两种类型：一为地震事件成因砂体与正常沉积作用所形成的砂体（三角洲前缘砂体）的叠置；二为地震事件成因砂体与由地震作用导致的三角洲前缘滑塌再搬运而形成的浊积砂体的叠置。最后，建立了不同沉积作用所形成砂体的成因模式。
关键词:
鄂尔多斯盆地,
长6油层组,
液化变形构造,
变形构造成因,
砂体叠置关系,
成因模式
CLC Number:
Tian Jingchun, Wang Wenzhi, Wang Feng, Wang Weihong, Zhang Jinquan. Palaeoearthquake deformation structures of the Chang 6 interval of Upper Triassic Yanchang Formation and superimposed relationship between sandbodies in Huachi-Qingyang area of Ordos Basin[J]. JOURNAL OF PALAEOGEOGRAPHY, 2012, 14(3): 303-310.
田景春 王文之 王 峰 王卫红 张锦泉. 鄂尔多斯盆地华池—庆阳地区上三叠统延长组长6油层组古地震变形构造及砂体叠置关系*[J]. 古地理学报, 2012, 14(3): 303-310.