| 渤海湾盆地中北部沉降史分析及裂后期异常沉降分离 |
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| 引用本文： | 白玉,刘少峰,李超,马方彬.渤海湾盆地中北部沉降史分析及裂后期异常沉降分离[J].高校地质学报,2016,22(3):530. |
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| 作者姓名： | 白玉 刘少峰 李超 马方彬 |
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| 摘 要： | 为了探究渤海湾盆地新生代沉降过程与西太平洋板块俯冲过程的对应关系,作者收集整理27口钻孔和1条地震地质剖面数据,并运用回剥技术和应变速率反演方法,模拟出渤海湾盆地中北部裂陷期地壳应变速率变化,分离出裂后期异常沉降。模拟获得裂陷期地壳应变速率曲线具有明显的三次大的波动,可指示三次构造沉降事件:裂陷Ⅰ幕(60~42 Ma),对应于渤海湾盆地孔店组—沙四段沉积过程,平均构造沉降速率为4.6 m/Ma;裂陷Ⅱ幕(42~36 Ma),对应沙三段—沙二段沉积过程,平均构造沉降速率为5.5~30.5 m/Ma;裂陷Ⅲ幕(36~24.6 Ma),对应于沙一段—东营组沉积过程,平均构造沉降速率为14.7~54.7 m/Ma。研究区内裂后期观测构造沉降与模拟的理论值存在明显的差异,即存在异常沉降。盆地北部异常沉降值在100~200 m,中部渤海海域异常沉降值在500~700 m,裂后期异常沉降向海域增大。作者推测渤海湾盆地裂后异常沉降主要是太平洋板块俯冲诱发的深部地幔物质流动导致向下拖拽力引起的。因此,渤海湾盆地中异常沉降可能是一种动力沉降。
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| 关 键 词： | 渤海湾盆地 新生代 回剥 应变速率反演 动力沉降 |
Subsidence History Analysis and Separation of Anomalous Subsidence During the Post-rift Stage in the Central and Northern |
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| BAI Yu,LIU Shaofeng,LI Chao,MA Fangbin.Subsidence History Analysis and Separation of Anomalous Subsidence During the Post-rift Stage in the Central and Northern[J].Geological Journal of China Universities,2016,22(3):530. |
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| Authors: | BAI Yu LIU Shaofeng LI Chao MA Fangbin |
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| Abstract: | In order to explore the relationship between the anomalous subsidence during the post-rift stage in the central and northern
Bohai Bay Basin and the process of the western pacific plate subduction, we collected and compiled data from 27 wells and one seismic
profile and a geological cross-section. We also simulated the strain rate of the crust during the syn-rift stage and the anomalous
subsidence during the post-rift stage for each borehole by using the back-stripping technology and the strain rate inversion method. Thesubsidence events. The average tectonic subsidence rate is 4.6 m/Ma during the first episode (60~42 Ma), corresponding to Ek-Es4, is
5.5~30.5 m/Ma during the second episode (42~36 Ma), corresponding to Es3-Es2, and is 14.7~54.7 m/Ma during the third episode
(36~24.6 Ma), corresponding to Es1-Ed. There are obvious differences between the observed tectonic subsidence and the simulated
subsidence during the post-rift stage in the study region, which indicate the anomalous subsidence. The anomalous subsidence in the
northern region is about 100~200 m and is about 500~700 m in the central Bohai sea region, the anomalous subsidence during the
post-rift stage increases towards the sea. The post-rift anomalous subsidence was probably caused by the subduction of the Pacific Plate,
which induced a down-drag force due to the flow of the deep mantle material. Therefore, the anomalous subsidence in Bohai Bay Basin
might be related to dynamic subsidence. |
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| Keywords: | Bohai Bay Basin Cenozoic backstripping the strain rate of inversion dynamic subsidence |
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