| DOI: | 10.1016/j.quascirev.2014.05.011
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| Scopus记录号: | 2-s2.0-84902010589
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| 论文题名: | Ice-load induced tectonics controlled tunnel valley evolution - instances from the southwestern Baltic Sea |
| 作者: | Al Hseinat M.; Hübscher C.
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| 刊名: | Quaternary Science Reviews
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| ISSN: | 2773791
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| 出版年: | 2014
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| 卷: | 97 | | 起始页码: | 121
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| 结束页码: | 135
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| 语种: | 英语
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| 英文关键词: | Bay of kiel
; Cretaceous pockmarks
; Glaciogenic unconformity
; Glückstadt graben
; Reflection seismics
; Tunnel valleys
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| Scopus关键词: | Erosion
; Glacial geology
; Glaciers
; Ice
; Landforms
; Underwater construction
; Bay of kiel
; Cretaceous pockmarks
; Differential subsidence
; Glaciogenic unconformity
; Multi-channel seismic
; Reflection seismics
; South-western baltic seas
; Strike-slip deformation
; Faulting
; conceptual framework
; Cretaceous
; echo sounder
; fault slip
; glacier
; ice sheet
; induced response
; strike-slip fault
; tectonic evolution
; tectonics
; topography
; tunnel
; Atlantic Ocean
; Baltic Sea
; Germany
; Gluckstadt
; Schleswig-Holstein
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| 英文摘要: | Advancing ice sheets have a strong impact on the earth's topography. For example, they leave behind an erosional unconformity, bulldozer the underlying strata and form tunnel valleys, primarily by subglacial melt-water erosion and secondarily by direct glacial erosion. The conceptual models of the reactivation of faults within the upper crust, due to the ice sheets' load, are also established. However, this phenomenon is also rather under-explored. Here, we propose a causal link between ice-load induced tectonics, the generation of near-vertical faults in the upper crust above an inherited deep-rooted fault and the evolution of tunnel valleys. The Kossau tunnel valley in the southeastern Bay of Kiel has been surveyed by means of high-resolution multi-channel seismic and echosounder data. It strikes almost south to north and can be mapped over a distance of ca 50km. It is 1200-8000m wide with a valley of up to 200m deep. Quaternary deposits fill the valley and cover the adjacent glaciogenic unconformity. A near-vertical fault system with an apparent dip angle of >80°, which reaches from the top Zechstein upwards into the Quaternary, underlies the valley. The fault partially pierces the seafloor and growth is observed within the uppermost Quaternary strata only. Consequently, the fault evolved in the Late Quaternary. The fault is associated with an anticline that is between 700 and 3000m wide and about 20-40m high. The fault-anticline assemblage neither resembles any typical extensional, compressional or strike-slip deformation pattern, nor is it related to salt tectonics. Based on the observed position and deformation pattern of the fault-anticline assemblage, we suggest that these structures formed as a consequence of the differential ice-load induced tectonics above an inherited deep-rooted sub-salt fault related to the Glückstadt Graben. Lateral variations in the ice-load during the ice sheet's advance caused differential subsidence, thus rejuvenating the deep-rooted fault. As a result, the inherited fault propagated upwards across the Zechstein and post-Permian overburden and further grew during the ice sheet's retreat. The developing fault and anticline system under the ice sheet created a weakness zone that facilitated erosion by pressurized glacial and subglacial melt-water, as well as by the glaciers themselves. Near-vertical faults cutting through the post-Permian are abundant in the southwestern Baltic realm, which implies that the ice-load induced tectonic activity described above was not an isolated incident. © 2014 Elsevier Ltd. |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/60219
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| Appears in Collections: | 过去全球变化的重建
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作者单位: | Institute of Geophysics, Center for Earth System Research and Sustainability, University of Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany
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| Recommended Citation: | |
Al Hseinat M.,Hübscher C.. Ice-load induced tectonics controlled tunnel valley evolution - instances from the southwestern Baltic Sea[J]. Quaternary Science Reviews,2014-01-01,97
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