摘要
通过对济阳坳陷几何学和一系列钻井和地震资料的综合分析,认为盆区存在伸展式、走滑式、反转式等三种基本构造样式;按几何学和成因学特征.可进一步分为翘倾断块式、滑动断阶式、潜山披覆式、重力背形式、底辟等5 种次级构造样式。伸展式是济阳坳陷最重要的构造样式,次级构造样式的发育和演化与地质体在坳陷中的构造位置关系密切:翘倾断块构造大部分形成在坳陷的缓坡带,滑动断阶构主要发育在坳陷的陡坡带,底辟构造常见于坳陷的洼陷带,潜山披覆构造多发育在盆地四周隆起区与洼陷中的潜山带,而重力背形构造大多发育在主断层的下降盘。盆地内的重力构造作用可随着沉积加厚作用的持续或加剧而逐渐增强,发育在济阳坳陷东部地区的一系列雁列式和帚状构造是郯庐断裂强烈走滑剪切作用的结果。研究证实,受早、晚白垩纪之交区域构造背景变化的影响,盆区应力场曾发生过从挤压作用向伸展作用的转换,导致济阳坳陷中的反转构造普遍发育,并具有东强西弱的时空演化规律。因此,走滑剪切式构造是郯庐断裂走滑剪切的结果,而反转式构造则是区域构造背景发生转化的产物。
According to synthetical analysis on geometry and drilling holes and seismic data in the Jiyang Depression, the authors obtained some new recognition on the structural styles of basin. Three basic styles of extensional-type, strike-slip-type and inversion-type were proposed in the paper. Of them, the extensional-type structural style is the most important one in the studied area and was describled in detail. From geometry and forming mechanism, five secondary styles of the extensional-type structural style, including tilted faulted-block, slide faulted-ramp, buried hill draping, gravitative antiform and diapir, were reported. There exists a close connection between the type of secondary structural style and the location of geological body in the depression: the tilted faulted-block style is developed mainly in the gentle slope zone of depression, the slide faulted-ramp style is mainly distributed in the steep zone, the diapir-type structure occurs in the depression zone, the buried hill draping style is developed in the uplifting areas around basin and the buried hill zone of depression, and the gravitical antiform was formed in the down-sliding side of main fault. Results suggest that with the thicken deposit of basin, gravitical working becomes more and more important in generation of structural styles. Under the strike-slip shearing of the Tan-Lu fault zone, a lot of en echelon and brush structures were formed in the eastern part of the Jiyang Depression. Owing to transformation of regional tectonic settings, a transformation of stress field from compression to extension took place in the studied area during the early Late Cretaceous, producing a series of negative inversion structures in the basins and the stress field became weaker and weaker from the east to the west. Thus, the strikeslip structural style is resulted from strong shearing of the Tan-Lu fault zone, and the inversion structural style is caused by transformation of regional tectonic settings.
出处
《高校地质学报》
CAS
CSCD
北大核心
2005年第4期622-632,共11页
Geological Journal of China Universities
基金
中国石油化工集团股份公司科技攻关项目(P04023)国家自然基金项目(40572118)资助
关键词
构造样式
伸展构造
走滑构造
负反转构造
济阳坳陷
structural style
extensional structure
strike-slip shear structure
negative inversion structure
Jiyang Depression