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Precipitation and flocculation of spherical nano-silica in North Sea chalk

Published online by Cambridge University Press:  09 July 2018

F. Jakobsen ,
H. Lindgreen  and
N. Springer
F. Jakobsen*
Affiliation:
Geological Survey of Denmark and Greenland, Thoravej 8, DK-2400 Copenhagen, Denmark
H. Lindgreen
Affiliation:
Geological Survey of Denmark and Greenland, Thoravej 8, DK-2400 Copenhagen, Denmark
N. Springer
Affiliation:
Geological Survey of Denmark and Greenland, Thoravej 8, DK-2400 Copenhagen, Denmark
*
*E-mail: fj@geus.dk
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Abstract

In the Maastrichtian-Danian chalk in the North Sea, discrete intervals, appearing as normal white chalk, contain up to 60% α-quartz <2 μm in size. Atomic force microscopy (AFM) reveals that the particles are of nm size, appearing as spherical particles and aggregates. Similar particles consisting of opal-CT were found in surface exposures of chalk in Denmark. Two new abiogenic pathways of silica formation in chalk are proposed. The first model proposes that SiO2 nano-size particles and aggregates precipitated and flocculated in the free-water phase as opal and were diagenetically transformed from opal-CT at low temperature to α-quartz at elevated temperature. In the second model, the dominance of radiolarians in the deep-water environment of the North Sea resulted in low dissolution supply with subsequent precipitation and flocculation of nano-size α-quartz particles. In the shallower water of the shelf environment of the present onshore chalk, the abundance of sponges and their dissolution supplied enough Si to precipitate opal-CT in the free-water phase.

Keywords

flocculationnano-silicaNorth Sea
Type
Research Article
Information
Clay Minerals , Volume 35 , Issue 1 , March 2000 , pp. 175 - 184
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2000

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References

Andersen, M.A., Christensen, H.F., Foged, N., Lind, I., Olsen, D., Springer, N. & Øyno, L. (1996) Joint Chalk Research Phase IV, Project 5: Rock Mechanics and Water Injection. Fifth North Sea Chalk Symposium, Reims, France.Google Scholar
Bromley, R.G., Schultz, M.G. & Peake, N.B. (1975) Paramoudras: giant flints, long burrows and the early diagenesis of chalks. Kong. Danske Vidensk. Selsk. Biol. Skr. 20, 10, Copenhagen.Google Scholar
Deconinck, J.F. & Chamley, H. (1995) Diversity of smectite origins in Late Cretaceous sediments: example of chalks from northern France. Clay Miner. 30, 30–365.Google Scholar
Ernst, W.G. & Calvert, S.E. (1969) An experimental study of the recrystallization of porcelanite and its bearing on the origin of some bedded cherts. Am. J. Sci., 267-A, 114-133.Google Scholar
Froehlich, F. (1974) Nature, importance relative et place dans la diagenèse des phases de silice présentes dans les silicifications de craies du Bassin océanique de Madagascar (Océan Indien) et du Bassin de Paris. Bull. Soc. Géol. Fr. 16, 16–498.Google Scholar
Guthrie, G.D., Bish, D.L. & Reynolds, R.C. (1995) Modelling the X-ray diffraction pattern of opal-CT. Am. Miner., 80, 80–869.Google Scholar
Heath, G.R. & Moberly, R. Jr. (1971) Cherts from the western Pacific, Leg 7 deep Sea Drilling Project. Pp. 991-1007 in: Initial Reports of the Deep Sea Drilling Project, vol. III , 991-1007 (US Government Printing Office).Google Scholar
Hicks, P.J. (1996) X-ray computer-assisted tomography for laboratory core studies. J. Petrol. Tech. 1120-1122.Google Scholar
Japsen, P. (1993) Influence of lithology and neogene uplift on seismic velocities in Denmark: Implications for depth conversions of maps. Am. Assoc. Petrol. Geol. Bull. 77, 77–194.Google Scholar
Jeans, C.V. (1968) The origin of the montmorillonite of the European chalk with special reference to the Lower Chalk of England. Clay Miner. 7, 7–311.Google Scholar
Jeans, C.V. (1978) Silifications and associated clay assemblages in the Cretaceous marine sediments of Southern England. Clay Miner. 13, 13–101.Google Scholar
Jørgensen, N.O. (1986) Geochemistry, diagenesis and nannofacies of chalk in the North Sea Central Graben. Sed. Geol. 48, 48–267.Google Scholar
Kastner, M., Keene, J.B. & Gieskes, J.M. (1977) Diagenesis of siliceous oozes-I. Chemical controls on the rate of opal-A to opal-CT transformation - an experimental study. Geochim. Cosmochim. Acta, 41, 41–1041.Google Scholar
Khoury, H.N. (1986) The origin of tripoli in Jordan. Sed. Geol. 48, 48–223.Google Scholar
Littke, R., Fourtanier, E., Thurow, J. & Taylor, E. (1991) Silica diagenesis and its effects on lithification of Broken ridge deposits, Central Indian Ocean. Proc. Ocean Drilling Program, Sci. Results, 121, 121–261.Google Scholar
Mackenzie, F.T. & Gees, R. (1971) Quartz: Synthesis at earth-surface conditions. Science, 173, 173–533.Google Scholar
Maliva, R.G. & Dickson, J.A.D. (1992) Microfacies and diagenetic controls of porosity in Cretaceous/ Tertiary chalks, Eldfisk Field, Norwegian North Sea. Am. Assoc. Petrol. Geol. Bull. 76, 76–1825.Google Scholar
Millot, G. (1970) Geology of Clays. Springer Verlag, London.Google Scholar
Morey, G.W., Fournier, R.O. & Rowe, J.J. (1962) The solubility of quartz in water in the temperature interval from 25°C to 300°C. Geochim. Cosmochim. Acta, 26, 26–1029.Google Scholar
Noe-Nygaard, N. & Surlyk, F. (1985) Mound bedding in a sponge-rich Coniacian chalk, Bornholm, Denmark. Bull. Geol. Soc. Denmark, 34, 34–237.Google Scholar
Pomerol, B. & Aubry, M.P. (1977) Relation between Western European chalks and opening of the North Atlantic. J. Sed. Pet. 47, 47–1027.Google Scholar
Stein, C.L. & Kirkpatrick, R.J. (1976) Experimental porcelanite recrystallization kinetics: A nucleation and growth model. J. Sed. Pet. 46, 46–430.Google Scholar
Williams, L.A. & Crerar, D.A. (1985) Silica diagenesis, II. General mechanisms. J. Sed. Pet. 55, 55–312.Google Scholar
Williams, L.A., Parks, G.A. & Crerar, D.A. (1985) Silica diagenesis, I. Solubility controls. I Sed. Pet. 55, 55–301.Google Scholar
Zijlstra, H.J.P. (1987) Early diagenetic silica precipitation, in relation to redox boundaries and bacterial metabolism, in Late Cretaceous chalk of the Maastrichtian type locality. Geol. Mijn. 66, 66–343.Google Scholar