Możliwości wykorzystania badań grawimetrycznych do poszukiwań i rozpoznania złóż węgla brunatnego w Polsce

Abstract

POSSIBILITIES OF USING THE GRAVIMETRIC MEASUREMENTS IN PROSPECTION AND INVESTIGATION OF BROWN COAL DEPOSITS IN POLAND Summary As a result of regional gravimetric survey of Poland, the local gravity anomalies occurring in quantities have been ascertained. In the area of the Fore-Sudetic monocline interesting are negative anomalies disclosing a longitudinal axis several times longer than the cross axis, and a considerable gradient. Drillings made within one of such anomalies in the region of Poznań have shown that the anomaly is not connected with a salt dome, as it was previously supposed, but with an erosional graben in the Jurassic substratum, filled up by the Tertiary deposits containing brown coal. The results of drillings made in the occurrence areas of other anomalies of this type and the interpretation of geological and geophysical data allow to assume that all the anomalies are connected with the contrast of density between the Jurassic or Triassic substratum and the Tertiary formations filling up the depressions in this substratum. It should be supposed that this phenomenon does not occur in the neighbouring areas where the Tertiary rests on the Cretaceous deposits of similar density. Basing on the previous experiences collected in Poland the author proposes a new method of prospection and investigation of brown coal deposits, which depends upon a complex application of gravimetric measurements using various density of measuring points and drillings.