Najpłytsze podłoże krystaliczne polskiej części platformy wschodnioeuropejskiej w strefie podlaskiej
Abstract
The shallowest crystalline basement of the Polish part of the East European Platform in the Podlasie Belt.
A b s t r a c t. The intensive development of studies on the crystalline basement of the Polish part of the East European Platform started only in the mid-1950s. These studies were based on geophysical research that preceded planned deep drilling projects. Twenty-five drill holes were located along four sections called: Białowieża, Kruszyniany, Sokółka and Krasnopol. The aim of this article is to re-evaluate drilling materials in the light of a variety of data, mainly structural data obtained from 20 boreholes from the first three “drilling sections”. All these sections were located on the Belarus-Lithuanian Elevation where the crystalline basement occurs at the shallowest depths. Special attention was paid to the recognition of ductile shear zones, SM foliation, LM mineral lineation and kinematic indicators. The results of the studies made it possible to identify the direction of tectonic transport, mainly with the top-to-SW, S and W, and deformation regimes in the boreholes of the Podlasie Belt. The main deformations have been related to a compressional regime in the amphibolite and granulite facies of regional metamorphism during the Svecofennian orogeny. It is
suggested for the future to combine the research efforts of specialists from different fields of geological sciences. However, due to the scarcity of core material from old drillings, the most important are new deep boreholes that will provide a lot of drilling material to explain the geological structure and the evolution of the Proterozoic basement of NE Poland.
A b s t r a c t. The intensive development of studies on the crystalline basement of the Polish part of the East European Platform started only in the mid-1950s. These studies were based on geophysical research that preceded planned deep drilling projects. Twenty-five drill holes were located along four sections called: Białowieża, Kruszyniany, Sokółka and Krasnopol. The aim of this article is to re-evaluate drilling materials in the light of a variety of data, mainly structural data obtained from 20 boreholes from the first three “drilling sections”. All these sections were located on the Belarus-Lithuanian Elevation where the crystalline basement occurs at the shallowest depths. Special attention was paid to the recognition of ductile shear zones, SM foliation, LM mineral lineation and kinematic indicators. The results of the studies made it possible to identify the direction of tectonic transport, mainly with the top-to-SW, S and W, and deformation regimes in the boreholes of the Podlasie Belt. The main deformations have been related to a compressional regime in the amphibolite and granulite facies of regional metamorphism during the Svecofennian orogeny. It is
suggested for the future to combine the research efforts of specialists from different fields of geological sciences. However, due to the scarcity of core material from old drillings, the most important are new deep boreholes that will provide a lot of drilling material to explain the geological structure and the evolution of the Proterozoic basement of NE Poland.