摘要:
主要通过钻井岩心观察和岩石薄片鉴定等手段对渤海湾盆地济阳坳陷古近纪环状层理进行研究。研究结果表明,济阳坳陷古近纪软沉积物变形层中的环状层理类型多样,形态复杂,计有光滑圆环状及蝌蚪状带“小尾巴”的环状层理、马尾丝或串珠状不规则环圈的环状层理、与阶梯状微断裂伴生的环状层理、链条状环状层理群、纺锤型环状层理群和中心为“飞石”环圈较光滑的环状层理等6种。综合分析认为震动塌落、震动拉伸变形、地震断裂面的摩擦作用、氧化还原反应和扩散作用是环状层理的主要成因,前三种成因的环状层理往往与其他震成构造伴生,可作为震积岩的良好标志。环状层理的其他成因还包括:地震波传播方式的影响、地球自转产生的涡旋的影响、“滚雪球”效应、间歇胶结作用以及生物成因等。研究环状层理必须综合考虑构造位置、应力条件、沉积环境,沉积特征、围岩条件等因素的影响和控制作用。
关键词:
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环状层理 /
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成因 /
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震积岩 /
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古近系 /
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济阳坳陷
Abstract:
The characteristics and formation of loop bedding of Paleogene in Jiyang sub-basin were studied through cores observation and rock slices identification mainly. There are 6kinks of loop bedding, such as smooth polliwog shape, horsetail or pinch-and-swell loop, associated with syn-sedimentary microfracture, catenarian loop bedding group, spindle loop bedding group and loop bedding with a slungshot as core in the studied area. Four main formations of loop bedding in Jiyang sub-basin were upper layers fall down in the process of earthquake, tautening distortion due to earthquake, the frication of earthquake-related surface of fault and the effect of redox and diffuse other formations of loop bedding comprise the effect of earthquake wave, the effect coming from circumrotate of globosity rotation, "snowball" function, cementation intermittent, the effect of biology, and so on. The tectonic location, stress condition, sedimentary environment, sediment characteristic and wall rock condition are the elementary factors considered in loop bedding study.