| 山东省灵山岛下白垩统浊积岩中与滑塌作用相关的软沉积物变形构造 |
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| 引用本文： | 梁钊,周瑶琪.山东省灵山岛下白垩统浊积岩中与滑塌作用相关的软沉积物变形构造[J].地球科学,2017,42(10):1715-1724. |
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| 作者姓名： | 梁钊 周瑶琪 |
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| 作者单位： | 中国石油大学地球科学与技术学院，山东青岛266580 |
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| 基金项目： | 国家自然科学基金项目41322013“深地资源勘查开采”重大科技创新工程项目2017CXGC1608 |
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| 摘 要： | 灵山岛上出露的软沉积物变形构造其成因具有多样性，而灯塔剖面底部滑塌层内的变形构造的触发因素尚不明确.结合野外观察和极射赤平投影方法，研究了滑塌层和内部变形构造的形成过程、触发机制和地质意义，结果表明:灯塔剖面主要由浊积岩沉积序列组成.滑塌层夹在未变形层之间，由地震触发形成，内部发育4个滑脱面，将滑塌层划分为5个变形单元，缩短率和变形程度各不相同.软沉积物变形构造主要为褶皱，形态特征表现为砂岩厚度在枢纽部位大大增加，也可见一些砂岩增厚和减薄现象，两者均是液化的砂岩在驱动力作用下的结果.滑塌过程中，滑塌层中的砂泥岩与海底沉积物之间的孔隙流体自由交换被切断，产生了暂时性的超压，导致了液化的发生.褶皱的轴线延伸方向为SSW-NNE，轴面倾斜方向主要为SEE(120°)，指示古水流主要来自SEE方向，与浊积岩内底痕指示的古水流方向一致，说明斜坡沉积系统上发育的滑塌褶皱能够指示古水流方向.
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| 关 键 词： | 滑塌褶皱 软沉积物变形构造 液化作用 浊积岩 灵山岛 沉积学 构造地质 |
| 收稿时间： | 2017-02-11 |
Soft-Sediment Deformation Structures Related to Slumping in Lower Cretaceous Turbidite in Lingshan Island,Shandong Province |
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| Abstract: | The origins of the soft-sediment deformation structures outcropped in Lingshan Island are diverse, and that the trigger of the deformation structures in the lowermost part of the Dengta section is in dispute. This contribution studied the forming processes, trigger agents and geological significance of the slump and the included structures combining yield observation and stereographic projection methods. The results show that Dengta section mainly consists of turbidite sequence. The deformed horizon is sandwiched between undeformed layers and triggered by earthquake. 4 decollement surfaces occurred internally, dividing the slump into 5 units which were different from each other in shortening and deformation degree. The main type of soft-sediment deformation is fold which display thickened fold hinge in sandstone, and layer thickening and thinning occur occasionally, both are deformations of liquefied sand under the action of driving forces. The folded sand layer and mud layer became isolated from pore-fluid communication with the sea-floor during slumping, in consequence they became temporarily overpressured, allowing the liquefaction of sand to take place. The fold axes are mainly oriented SSW-NNE, and the axial planes mainly dip to SEE (120°), both indicating the flows coming mainly from SEE. This result is consistent with the regional paleocurrent measurements from the sole marks in turbidites. Therefore, the folds in slump that develop in the subaqueous slope system have significance in indicating paleocurrent direction. |
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