Open AccessLate Cenozoic basin development of the eastern North Sea Basin
Author(s) -
Olaf Michelsen
Publication year - 1996
Publication title -
bulletin of the geological society of denmark
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.674
H-Index - 28
eISSN - 2245-7070
pISSN - 0011-6297
DOI - 10.37570/bgsd-1996-43-02
Subject(s) - geology , cenozoic , marine transgression , structural basin , paleontology , cretaceous , unconformity , sedimentary rock , subsidence , late miocene , fluvial , middle miocene disruption , quaternary , sedimentation , geomorphology , sediment
The Cenozoic succession in the Danish part of the North Sea Basin includes twosignificant breaks in sedimentation; 1) at the Eocene-Oligocene boundary and 2)at mid Miocene time.The sediment transport direction was from the west during the Middle-LateEocene and mainly from northeast and east in post Eocene times, and a changefrom a concordant seismic reflection pattern to a progradational pattern is seen. Aclear change in Iithology occurs at the Eocene-Oligocene boundary, from a finegrained clay-dominated deposit below the boundary to a clay with silt and micaabove. Near shore marine and fluvial sediments of Early Oligocene to mid Mioceneage are known from the offshore and onshore areas, witnessing that the coastlinemigrated into the basin for the first time since the earliest Cretaceous. This changein sedimentation pattern was probably caused by the initial uplift of Scandinavia.At mid Miocene time a significant environmental change occurred in the NorthSea. A change from dark coloured to light coloured deposits indicates introduction of a well-oxygenated environment. A marked increase in rate of sedimentation (and subsidence) is evidenced by the approx. 1500 m thick sedimentary package in the central part of the basin. Late Middle Miocene starved sedimentationseen in the central North Sea may indicate a significant increase in subsidencerates.The base of the Quaternary is a major erosional unconformity, mainly createdby erosion caused by uplift of Scandinavia. 1000-1200 m of uplift is calculatedfor the eastern part of the North Sea Basin. With a post-Eocene subsidence of2500 m in the central North Sea, the amplitude of the post-Eocene tectonic movements is approx. 3700 m.