黄海西部全新世泥质楔形沉积体的地震识别

    SEISMIC IDENTIFICATION OF THE HOLOCENE MUD CLINOFORM IN WESTERN YELLOW SEA

    • 摘要: 通过分析2 000 km单道地震资料的瞬时振幅强弱和瞬时相位异常,对山东半岛近岸全新世楔形沉积体的形态及分布特征进行了研究。该泥楔呈中间厚、两侧薄的形态,覆盖区域的海底有明显的凸起,向岸侧坡度较小,以较小的角度缓慢抬升,达到最大高度之后以一定角度向海倾斜;泥楔的底界面基本水平,明显切割下伏地层。该泥楔由山东半岛东北侧开始向东、南方向分布,绕过山东半岛东侧之后继续向南或西南方向延伸,形成了一个近似于"γ"形状的沉积体环绕山东半岛。它由近岸端向远岸端逐渐加厚然后再减薄,最大厚度分别位于山东半岛东北和西南(60 m以上),并以这2处为中心向四周逐渐减薄。泥楔从北到南覆盖了山东半岛东部约36 111 km2的海底,总体积约有440 km3,总质量约为527×109 t,泥楔沉积区从11 cal.ka BP至今的平均沉积量可以达到0.37×109 t/a之多。

       

      Abstract: The instantaneous amplitude variation and instantaneous phase anomaly of the single channel seismic profiles reveal the form and distribution of the Holocene mud clinoform off the Shandong Peninsula. The mud clinoform is thick in middle and thin at wedge, while the seafloor where it is covered has obviously risen to the peak and then lean to the shoreward with a smaller angle. The horizontal bottom interface cuts the underlying strata. The γ-shaped mud clinoform surrounds the Shandong Peninsula, spreading to east and south from northeast Peninsula, and extending to south and southwest after bypassing eastern part of the Peninsula. It becomes thicker from the offshore to far shore, and the maximum thickness locations are in the northeast and southwest of Shandong Peninsula (more than 60 m), and with these two locations as centers it changes gradually thinner and thinner. It covers about 36 111 km2 of the seafloor, and with the volume about 440 km3 and mass about 527×109 t. The average sediment volume of the mud clinoform area may reach more than 0.37×109 t/a ever since 11 cal. ka BP.

       

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