Tectonostratigraphic framework and depositional history of the Cretaceous–Danian succession of the Danish Central Graben (North Sea) – new light on a mature area

2017 ◽  
Vol 8 (1) ◽  
pp. 9-46 ◽  
Author(s):  
F. S. P. van Buchem ◽  
F. W. H. Smit ◽  
G. J. A. Buijs ◽  
B. Trudgill ◽  
P.-H. Larsen

AbstractAn integrated tectonic and sequence stratigraphic analysis of the Cretaceous and Danian of the Danish Central Graben has led to significant new insights critical for our understanding of the chalk facies as a unique cool-water carbonate system, as well as for the evaluation of its potential remaining economic significance.A major regional unconformity in the middle of the Upper Cretaceous chalk has been dated as being of early Campanian age. It separates two distinctly different basin types: a thermal contraction early post-rift basin (Valanginian–Santonian), which was succeeded by an inversion tectonics-affected basin (Campanian–Danian). The infill patterns for these two basin types are dramatically different as a result of the changing influence of the tectonic, palaeoceanographic and eustatic controlling factors.Several new insights are reported for the Lower Cretaceous: a new depositional model for chalk deposition along the basin margins on shallow shelves, which impacts reservoir quality trends; recognition of a late Aptian long-lasting sea-level lowstand (which hosts lowstand sandstone reservoirs in other parts of the North Sea Basin); and, finally, the observation that Barremian–Aptian sequences can be correlated from the Boreal to the Tethyan domain. In contrast, the Late Cretaceous sedimentation patterns have a strong synsedimentary local tectonic overprint (inversion) that influenced palaeoceanography through the intensification of bottom currents and, as a result, the depositional facies. In this context, four different chalk depositional systems are distinguished in the Chalk Group, with specific palaeogeography, depositional features and sediment composition.The first formalization of the lithostratigraphic subdivision of the Chalk Group in the Danish Central Graben is proposed, as well as an addition to the Cromer Knoll Group.

2005 ◽  
Vol 7 ◽  
pp. 21-24
Author(s):  
Poul Schiøler ◽  
Jan Andsbjerg ◽  
Ole R. Clausen ◽  
Gregers Dam ◽  
Karen Dybkjær ◽  
...  

Intense drilling activity following the discovery of the Siri Field in 1995 has resulted in an improved understanding of the siliciclastic Palaeogene succession in the Danish North Sea sector (Fig. 1). Many of the new wells were drilled in the search for oil reservoirs in sand bodies of Paleocene–Eocene age. The existing lithostratigraphy was based on data from a generation of wells that were drilled with deeper stratigraphic targets, with little or no interest in the overlying Palaeogene sediments, and thus did not adequately consider the significance of the Palaeogene sandstone units in the Danish sector. In order to improve the understanding of the distribution, morphology and age of the Palaeogene sediments, in particular the economically important sandstone bodies, a detailed study of this succession in the Danish North Sea has recently been undertaken. An important aim of the project was to update the lithostratigraphic framework on the basis of the new data.The project was carried out at the Geological Survey of Denmark and Greenland (GEUS) with participants from the University of Aarhus, DONG E&P and Statoil Norway, and was supported by the Danish Energy Agency. Most scientific results cannot be released until September 2006, but a revised lithostratigraphic scheme may be published prior to that date. Formal definition of new units and revision of the lithostratigraphy are in preparation. All of the widespread Palaeogene mudstone units in the North Sea have previously been formally established in Norwegian or British wells, and no reference sections exist in the Danish sector. As the lithology of a stratigraphic unit may vary slightly from one area to another, Danish reference wells have been identified during the present project, and the lithological descriptions of the formations have been expanded to include the appearance of the units in the Danish sector. Many of the sandstone bodies recently discovered in the Danish sector have a limited spatial distribution and were sourced from other areas than their contemporaneous counterparts in the Norwegian and British sectors. These sandstone bodies are therefore defined as new lithostratigraphic units in the Danish sector, and are assigned Danish type and reference sections. There is a high degree of lithological similarity between the Palaeogene–Neogene mudstone succession from Danish offshore boreholes and that from onshore exposures and boreholes, and some of the mudstone units indeed seem identical. However, in order to acknowledge the traditional distinction between offshore and onshore stratigraphic nomenclature, the two sets of nomenclature are kept separate herein. In recent years oil companies operating in the North Sea have developed various in-house lithostratigraphic charts for the Paleocene–Eocene sand and mudstone successions in the Danish and Norwegian sectors. A number of informal lithostratigraphic units have been adopted and widely used. In the present project, these units have been formally defined and described, maintaining their original names whenever feasible, with the aim of providing an unequivocal nomenclature for the Palaeogene – lower Neogene succession in the Danish sector. It has not been the intention to establish a sequence stratigraphic model for this succession in the North Sea; the reader is referred to the comprehensive works of Michelsen (1993), Neal et al. (1994), Mudge & Bujak (1994, 1996a, b), Michelsen et al. (1995, 1998), Danielsen et al. (1997) and Rasmussen (2004).


2008 ◽  
Author(s):  
Kevin Arthur Bourassa ◽  
Tove Husby ◽  
Rick Deuane Watts ◽  
Dale Oveson ◽  
Tommy M. Warren ◽  
...  

Author(s):  
P. E. P. Norton

SynopsisThis is a brief review intended to supply bases for prediction of future changes in the North Sea Benthos. It surveys long-term changes which are affecting the benthos. Any prediction must take into account change in temperature, depth, bottom type, tidal patterns, current patterns and zoogeography of the sea and the history of these is briefly touched on from late Tertiary times up to the present. From a prediction of changes in the benthos, certain information concerning the pelagic and planktonic biota could also be derived.


Clay Minerals ◽  
1990 ◽  
Vol 25 (4) ◽  
pp. 519-541 ◽  
Author(s):  
M. J. Pearson

AbstractClay mineral abundances in Mesozoic and Tertiary argillaceous strata from 15 exploration wells in the Inner and Outer Moray Firth, Viking Graben and East Shetland Basins of the northern North Sea have been determined in <0·2 µm fractions of cuttings samples. The clay assemblages of more deeply-buried samples cannot be unambiguously related to sedimentary input because of the diagenetic overprint which may account for much of the chlorite and related interstratified minerals. Other sediments, discussed on a regional basis and related to the geological history of the basins, are interpreted in terms of clay mineral provenance and control by climate, tectonic and volcanic activity. The distribution of illite-smectite can often be related to volcanic activity both in the Forties area during the M. Jurassic, and on the NE Atlantic continental margin during the U. Cretaceous-Early Tertiary which affected the North Sea more widely and left a prominent record in the Viking Graben and East Shetland Basin. Kaolinite associated with lignite-bearing sediments in the Outer Moray Firth Basin was probably derived by alteration of volcanic material in lagoonal or deltaic environments. Some U. Jurassic and L. Cretaceous sediments of the Inner Moray Basin are rich in illite-smectite, the origin of which is not clear.


Clay Minerals ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 135-149 ◽  
Author(s):  
D. M. Conybeare ◽  
H. F. Shaw

AbstractThe Palaeocene Everest Complex, located in the Central Graben of the North Sea, comprises interbedded sandstones and mudrocks deposited in a submarine fan environment and overlies Cretaceous limestones. Depositional facies are the main influence on reservoir quality, although the latter is reduced significantly locally by ferroan calcite cementation, particularly in the lower part of the complex. Carbon and O stable isotope analyses have been made from cements in sandstones and mudrocks and from shear fractures and injection features within mudrock intervals. These indicate a marine source of detrital carbonate becoming mixed with HCO3− from decarboxylation higher in the succession. Petrographic observation and microprobe analyses indicate that dissolution of coccoliths and foraminifera in limestones are the principal sources of cementation. The similar composition of cements in sandstones, fractures and injection features suggests a common formation. Burial history modelling shows cement precipitation is synchronous with periods of excess pressure and therefore excess pressure release associated with rock failure is proposed as a prominent mechanism for initiating cementation.


1991 ◽  
Author(s):  
Gary Hampson ◽  
Terje Hansen ◽  
H. Jakubowicz ◽  
John V. Kingston

2008 ◽  
Vol 65 (8) ◽  
pp. 1392-1397 ◽  
Author(s):  
Peter Heslenfeld ◽  
E. Lisette Enserink

Abstract Heslenfeld, P., and Enserink, E. L. 2008. OSPAR Ecological Quality Objectives: the utility of health indicators for the North Sea. – ICES Journal of Marine Science, 65: 1392–1397. Committed to the ecosystem approach to management, OSPAR has accumulated 15 years of experience in developing a conceptual framework for ecological indicators and objectives, and in applying the framework to the North Sea as a test case. These Ecological Quality Objectives (EcoQOs) have become a model for the implementation of the new European Marine Strategy Framework Directive. We describe the history of EcoQO development, its current status, and future needs. We also present our positive and negative experiences in developing the approach, and conclude that regional sea conventions and marine research institutes in Europe should join forces to accelerate the development of ecosystem indicators and objectives, using existing concepts.


2000 ◽  
Vol 137 (4) ◽  
pp. 381-394 ◽  
Author(s):  
S. LOUWYE ◽  
J. DE CONINCK ◽  
J. VERNIERS

Detailed dinoflagellate cyst analysis of the Lower–Middle Miocene Berchem Formation at the southernmost margin of the North Sea Basin (northern Belgium) allowed a precise biostratigraphical positioning and a reconstruction of the depositional history. The two lower members of the formation (Edegem Sands and decalcified Kiel Sands) are biostratigraphically regarded as one unit since no significant break within the dinocyst assemblages is observed. The base of this late (or latest) Aquitanian–Burdigalian unit coincides with sequence boundary Aq3/Bur1 as defined by Hardenbol and others, in work published in 1998. A hiatus at the Lower–Middle Miocene transition separates the upper member (the Antwerpen Sands) from the underlying member. The greater part of the Antwerpen Sands were deposited in a Langhian (latest Burdigalian?)–middle Serravallian interval. The base of this unit coincides with sequence boundary Bur5/Lan1. Biostratigraphical correlation points to a diachronous post-depositional decalcification within the formation since parts of the decalcified Kiel Sands can be correlated with parts of the calcareous fossil-bearing section, up to now interpreted as Antwerpen Sands. The dinoflagellate cyst assemblages are dominated by species with a inner neritic preference, although higher numbers of oceanic taxa in the upper part of the formation indicate incursions of oceanic watermasses into the confined depositional environment of the southern North Sea Basin.


2014 ◽  
Vol 35 (2) ◽  
pp. 200-219
Author(s):  
Eike-Christian Heine

The Kiel Canal (built between 1886 and 1895) connects the North Sea and the Baltic for seagoing vessels, yet, being 100 km long, about 10 m deep and 100 m wide, it also divides a landscape. This finding is the starting point for analysing the effects of infrastructure that facilitates communication and exchange but also produces obstructions and rivalries. This article explores the ambiguous effects this piece of infrastructure had on politics, technology, labour, trade and military strategy. The ‘deep ditch’ also had severe environmental consequences that were palpable until well into the twentieth century. By considering both the ‘positive’ and the ‘negative’ of the waterway, the narrative of ‘connect-and-divide’ avoids the still-too-often told affirmative story of transport infrastructure. Instead, it and opens the outlook to a multi-faceted history of transport infrastructures.


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