Formation Of Flint Horizons In North Sea Chalk Through Marine Geol342
In the Upper Cretaceous-Danian North Sea chalk, silica composed of nano-size quartz spheres is dispersed in the chalk matrix, and quartz is present in bands and nodules of flint.
Dec 01, 2012 Highlights Quartz in North Sea chalk. New model for formation of flint and nano-size spherical quartz particles in chalk. Formation by sedimentation of nano-quartz particles in the sea. Proportion of quartz determined by dissolution of calcite during sedimentation. Calcite dissolution probably due to acidification of the sea from volcanic eruptions.
tion and structure and presents a model for the formation of flint from nano-quartz in the North Sea Ekofisk chalk. Material and methods We have investigated core samples from the Ekofisk Forma-tion in the South Arne Field wells SA-1 and Rigs-1, in the Halfdan Field wells Sif-1 and Nana-1 and in the Gorm Field well N-22 Fig. 1.
Jan 01, 2012 In the Danish North Sea, the chalk of the Danian Ekofisk Formation is largely pelagic and includes horizons of claysized quartz andor clay minerals. The upper part of the Ekofisk Formation Ekofisk Porous has reservoir potential, whereas the lower part of the formation Ekofisk Tight is of low permeability. The Ekofisk Formation was studied in wells Rigs1, Rigs2 and SA ...
Aug 01, 2013 The Chalk Group Upper CretaceousLower Paleocene in the Norwegian Central Graben is of major importance as a hydrocarbon reservoir and has been the focus of research for more than 40 years see Surlyk et al., 2003 for an overview.Chalk is a biogenic sediment primarily deposited from the slow settlement of coccoliths in marine settings, with secondary inputs of foraminifers and ...
Sep 19, 2016 This study describes the first diagenetic stages of chalk from a loose carbonate ooze to a sedimentary rock. As a consequence, the origin and consequence
Seismic high-resolution Chirp proles from the well-documented submerged Stone Age settlement Atlit-Yam, located off Israels Carmel coast, display systematic disturbances within the water column not related to sea-oor cavitation, vegetation, sh
Highresolution shallow subbottom seismic survey data obtained for the Dudgeon windfarm site located 50 km offshore of the north Norfolk coast in the southern North Sea have revealed that the chalk ...
The final permanent breaching of the Cretaceous chalk at the Strait of Dover during the Saalian Marine Isotope Stage 6, MIS 6 ice age led to the formation of the Eurogeul belt, a gravelly sand belt that represents the largest concentration of gravelly fluvial sediments in the southern North Sea. The formation and preservation of the ...
Sep 01, 2017 The Bolders Bank Formation is associated with the North Sea lobe Carr et al., 2006, Davies et al., 2011, and has recently been shown in the region SW of the DBZ to have formed through complex submarginal processes during the phased occupation and retreat of this dynamic ice lobe Dove et al., 2017. The Bolders Bank Formation has been ...
Jan 01, 2012 Firmgrounds formed by the second mechanism, or type 2 firmgrounds, mark omission surfaces within relatively shallow-shelf sea chalk successions. Omission surfaces characterized by the Glossifungites Ichnofacies occur only locally in North American chalk successions, for example, in the Austin Chalk of Texas Dawson and Reaser, 1990.
The widespread chalk distribution suggests that the partly enclosed North Sea Basin Figures 1 and 6 was part of a much bigger ecosystem which was connected to the North Atlantic and the Tethyan Realm e.g., Ineson et al., 2005 Vejb k et al., 2010 Blakey, 2011. The chalk ecosystem was characterized by uniform pelagic conditions without ...
Jan 01, 2014 A new model has recently been proposed for the formation of flint in Danian North Sea chalk, according to which nanoquartz spheres crystallized in the marine water column and were then deposited and compacted, ultimately forming flint. This depositional origin implies that apparently massive flint blocks may have a porous structure.
Jun 01, 2010 In the oil fields in the Central Graben of the North Sea, Maastrichtian chalk is an important hydrocarbon reservoir, but oil may also be found in the Danian chalk, consisting of white chalk interbedded with clay layers. Within the chalk section, discrete intervals appear like chalk but contain large amounts of quartz up to 100.
Mar 01, 2000 Formation of flint horizons in North Sea chalk through marine sedimentation of nano-quartz Clay Minerals. View More Related Book Content. Tectonostratigraphic framework and depositional history of the CretaceousDanian succession of the Danish Central Graben North Sea new light on a mature area ... Sedimentological evolution of Sele ...
Sep 01, 1982 Our measured section for Leigh Hill differs markedly from that published by Codrington 1865. Where the Hitch Wood Hardground is developed, the upper boundary of the Chalk Rock Formation is placed at the flint nodule horizon that marks the base of the overlying nodular chalk unit. This is effectively the surface of the Hitch Wood Hardground.
distinct hardness of this chalk, and lack of flint nodules contrasts the soft, off-white holostratotype at Seaford, Sussex. The Flintless Belt of the Newhaven Chalk Formation contains several compositional changes as well as a considerable amount of truncation. In some horizons the usual clay-size chalk
Mar 03, 2016 The original source of this flint was probably a now inundated chalk source north of Alderney ... The latter then located a flint horizon exposed in the cliff and has been instrumental in promoting awareness of this material and the threats to its existence caused by marine erosion to a wider audience, leading to the sites subsequent ...
Jun 24, 2014 Ice ages and marine isotope stages. Continuous records of Quaternary time are available from cores collected from the deep ocean and the Antarctic ice sheet .For the last 120,000 years, the Greenland ice sheet provides an additional high-resolution record, of particular relevance to the North Atlantic and the study area e.g. Lowe et al., Reference Lowe, Rasmussen, Bj rck, Hoek, Steffensen ...
Key figures from the history of research on the Foraminifera of the Chalk Group in the UK
Pectinid bivalves - Scallops e.g. Entolium from the Ferriby Chalk Formation Oysters are rare but can be found at some horizons. Oysters need to grow on a solid surface but the Chalk sea floor mostly consisted of soft white ooze. Brachiopods - lamp shells. These are common at certain levels in the Chalk.
Precipitation and flocculation of spherical nano-silica in North Sea chalk - Volume 35 Issue 1
Jan 01, 2012 In the Danish North Sea, the chalk of the Danian Ekofisk Formation is largely pelagic and includes horizons of claysized quartz andor clay minerals. The upper part of the Ekofisk Formation Ekofisk Porous has reservoir potential, whereas the lower part of the formation Ekofisk Tight is of low permeability.
The formation of flint remains open to discussion though Clayton 1986 has produced a convincing argument for its deposition triggered by geochemical activity at a redox boundary at shal low depth below the sea bed, Lithostratigraphic logging of the Chalk identifies flint at certain levels on a regional scale and many have characteristic ...
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