Aretz et al_2011.pdf - ORBi - Université de Liège

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Kölner Forum Geol. Paläont., 19 (2011)
M. ARETZ, S. DELCULÉE, J. DENAYER & E. POTY (Eds.)
Abstracts, 11th Symposium on Fossil Cnidaria and Sponges, Liège, August 19-29, 2011
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wackestones, packstones and grainstones in this well suggest a marine connection of this area with the
postulated Devonian ocean in the South East. Marine Givetian limestones are described in the German well
Q/1 and in the German well Munsterland-1, not too far from the German Dutch border. In the
Netherlands, mostly clastic sediments are found. Exceptions so far are some biostromal limestones in South
Limburg. Frasnian marine shales in some wells like S05-01 make it certain that a coastline covered part of
the Netherlands during the Middle Devonian. The new well information of the giant Devono-Mississippian
Groningen (ABBINK et al. 2009) and the Luttelgeest reef (VAN HULTEN & POTY 2009), suggest that the core of
these reefs were formed during the Devonian. A proposal for a new Devonian paleogeography of the area
will be made.
The new seismic interpretations have indicated massive up to 1-2000 m Mississippian carbonate buildups
over a large part of the Friesland province. The top of the Mississippian carbonates is at a depth of
3,000-6,000 m, sometimes exceeding 10,000 m. Like the Devonian, stratigraphic information is therefore
seriously limited, because the few wells that have reached the carbonates are mostly clustered at the
shallower basin fringes. In a number of Dutch wells, at the northern flank of the London-Brabant Massif,
900-1400 m thick light grey, brown carbonates have been encountered. Generally, it consists of a tight
limestone that ranges in age from Tournaisian to latest Viséan and is called the Zeeland Formation.
Sedimentologically they confirm a carbonate platform setting. These carbonates are very similar to platform
carbonates described in the UK southern North Sea and onshore. It is likely that different facies belts exist
related to the forming of half grabens. To the north fringe reefs or very thick carbonate microbialite reefs of
Mississippian exist. Comparable bioherms exist with associated good reservoir quality in the Caspian
region (WEBER et al. 2003), not proven in the Dutch reefs. Grainstone shoal deposits in the Caspian display
good reservoir potential where primary porosity is mainly controlled by intergranular porosity and mudlean
packstone lithofacies. Similar facies are not unknown in the Dinantian carbonate fringe area of
Belgium. A big question is if they can be expected in the Dutch northern fringe reefs.
ABBINK, O.A., DEVUYST, F.X., GRÖTSCH, J., HANCE, L., VAN HOOF, T.B., KOMBRINK, H. & VAN OJIK, K. (2009): The Lower
Carboniferous of key-well UHM-02, onshore The Netherlands, and implications for regional basin development. -
European Association of Geoscientists and Engineers, 71th Conference and Technical Exhibition, June 8-11,
Amsterdam, the Netherlands, extended abstracts W031, 5 p.
KOMBRINK, H. (2008): The Carboniferous of the Netherlands and surrounding areas; a basin analysis. - Geologica
Ultraiectina, No. 294, Ph.D. thesis University of Utrecht, 184 p.
VAN HULTEN, F.F.N. & POTY, E. (2008): Geological factors controlling Early Carboniferous carbonate platform
development in the Netherlands. - In: ARETZ, M., HERBIG, H.-G. & SOMERVILLE, I.D. (Eds.) Carboniferous Platforms
and Basins. Geological Journal, 43 (2-3): 175-196.
VAN HULTEN, F.F.N. & POTY, E. (2009): Dinantian Reefs underneath the Netherlands. - European Association of
Geoscientists and Engineers, 71th Conference and Technical Exhibition, June 8-11, Amsterdam, the Netherlands,
extended abstracts W039, 5 p.
WEBER, L.J., FRANCIS, B.P., HARRIS, P.M. & CLARK, M. (2003): Stratigraphy, facies, and reservoir characterization - Tengiz
Field, Kazakhstan. - In: AHR, W.M., HARRIS, P.M., MORGAN, W.A. & SOMERVILLE, I.D. (Eds.), Permo-Carboniferous
Carbonate Platforms and Reefs, Joint SEPM Special Publication, 78 - American Association of Petroleum Geologists,
Memoir, 83: 351-394.
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