REPORT ON SEISMIC RESEARCH FOR KARSTIFICATION ZONES IN THE VISEAN LIMESTONE ON THE NORTHERN FLANK OF THE BRABANT MASSIF
The mapping of the Visean limestone was undertaken with the seismic method. There were some expectations that karstification could be deduced from the seismic data, either directly on the basis of diffraction hyperbolae or indirectly by a change in amplitude and/or frequency content. A vibroseismic crew from Prakla-Seismos was used for data acquisition, data processing was done by Prakla-Seismos and Entec, interpretation by all participants. The seismic data were of high quality for the Tertiary and Cretaceous part of the section. For the Carboniferous part, data quality was in places low, the target horizon + the Visean limestone + was nearly everywhere only to be determined with difficulty. The only strong reflections from the Carboniferous part of the section come from the Westfalian which appears to be strongly folded and subsequently eroded. The Visean reflector was tied to the well Turnhout and + with some extrapolation + to the well Rijsbergen. The most important (negative result) of the first interpretation was that the Visean lies at much greater depth than one had expected on the basis of an earlier survey in the area around Hoogstraten. The top of the Visean limestone was expected between 1200 and 1800 m. This expectation was not borne out by the subject survey. A preliminary depth contour map based on rather uncertain reflections in all sections indicates that the Visean lies everywhere in the area of investigation deeper than 2000 m. In particular in the Dutch area depth is nearly everywhere greater than 3000 metres. The base of the Tertiary, the base of the Cretaceous and the top of the Visean have been mapped. A spectral investigation of the seismic line that is completely on Dutch territory indicates that the Visean has a depth of 4.5 km.
Bibliographic Reference: EUR 9323 EN (1984) MF, 35 P., BFR 120, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989122078500 / Last updated on: 1987-01-01
Available languages: en