Anomalous Cenozoic subsidence along the ‘passive’ continental margin from Ireland to mid-Norway     

S. Ceramicola  M. Stoker  D. Praeg  P.M. Shannon  L. De Santis  R. Hoult  B.O. Hjelstuen  S. Laberg  A. Mathiesen 《Marine and Petroleum Geology》2005,22(9-10):1045

Two-dimensional flexural backstripping and thermal modelling (assuming uniform stretching and cooling) is applied to four interpreted, depth-converted seismic profiles across the Rockall, Faroe–Shetland and Vøring basins, along 1600 km of the Atlantic continental margin of NW Europe. The results reveal a significant discrepancy between the modelled palaeo-depths for the base of the Cenozoic succession and those proven by geological evidence at control points (subaerial conditions or depositional depth ranges in wells). The discrepancy is of Rm-scale, much larger than the possible range of parameter error determined by sensitivity tests (up to 0.5 km). Assuming a Cretaceous rift episode (100 Ma), the discrepancy is at least 1.7 km in the Rockall Basin, up to 2.1 km in the Faroe–Shetland Basin and at least 1 km in the Vøring Basin (which also contains evidence of kilometre-scale uplift of the inner margin). Assuming (unproven) a second rift in the early Cenozoic (60 Ma), the discrepancy remains of kilometre-scale in the Rockall and Faroe–Shetland basins. The restorations also provide evidence of uplift, both above compressive structures and across the modelled profiles as seaward rotations of palaeo-bathymetric records. The palaeo-bathymetric discrepancy corresponds to an anomaly in subsidence that is the cumulative product of all the tectonic episodes that have affected the NW European margin, and may incorporate both permanent effects of the last episode of lithospheric extension and transient responses to the interaction of the margin with mantle convective flow. Any explanation must accommodate both the large magnitude of anomalous subsidence along the margin and evidence of its episodic character.  相似文献   

渤海湾盆地中北部沉降史分析及裂后期异常沉降分离          下载免费PDF全文

白玉  刘少峰  李超  马方彬 《高校地质学报》2016,22(3):530

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。  相似文献   

济阳坳陷中、新生代构造沉降与板块聚敛速率关系探讨   总被引：4，自引：0，他引：4  

张惬  贾东  陈竹新  王良书  陆建军  陈晓明 《高校地质学报》2005,11(4):642-648

根据回剥模型,将钻井资料与区域地震剖面相结合,对济阳坳陷内东营、沾化和惠民3个次一级凹陷进行沉降史模拟。6121钻井的沉降曲线表明济阳坳陷中、新生代的构造沉降分为6个阶段：（1）中生代残余盆地发展阶段;（2）孔店期初始裂谷阶段;（3）沙四-沙三期断陷一期;（4）沙二-沙-期断陷二期;（5）东营期断陷三期;（6）新近纪热沉降阶段。将以上构造沉降速率同太平洋板块相对欧亚板块的聚敛速率进行比较,两者相吻合,表明太平洋板块的俯冲作用是济阳坳陷从“初始裂谷-快速沉降-裂谷逐渐萎缩-热沉降”构造演化过程的主要控制因素。  相似文献   

Quantitative discrimination of normal fault segment growth and its geological significance: example from the Tanan Depression,Tamtsag Basin,Mongolia     

H. X. Wang  S. R. Liu  R. Chu  B. Liu  P. P. Shi 《Australian Journal of Earth Sciences》2018,65(5):711-725

This work focuses on quantitative discrimination of fault segment growth and its effect on sedimentation and stratigraphic evolution in the Tanan Depression, the Tamtsag Basin, Mongolia. Integrated seismic data sets and stratigraphic data suggest that normal faults evolve as fault segments grow, link and amalgamate to form a larger fault. Three main stages in the evolution of fault zone are recorded in the syn-rift stratigraphy. This paper applies a method to effectively discriminate the locus of fault segments by ‘three diagrams’ and quantitatively reconstruct process of fault growth by the maximum throw subtraction method. Backstripped to T₂₃ SB event, the F1 fault comprises four hard-linked segments, and the F2 fault is divided into four soft-linked segments (F2-4 and F2-5 segments are shown by hard linkage) at the T₂₃ structural level. The F1 and F2 fault comprise hard-linked segments at the T_23-1 structural level when the F1 and the F2 are backstripped to the T₂₂ (133.9 Ma) SB event. The F1 fault is divided into three soft-linked segments (F1-2 and F1-3 segments are shown by hard linkage), and the F2 fault is divided into four isolated fault segments at the T_23-1 structural level when the F1 and the F2 is backstripped to the T₂₃ SB event. Incorporation of paleo-fault geometry, isochron thickness map and sedimentary facies suggest that the transfer zone provided accommodation space for sediment discharge and deposition, and the depocentres were formed at the locus of maximum throw along a fault segment during its overall deposition.  相似文献