Geologiczno-surowcowe problemy kruszywa naturalnego w Polsce

Zdzisław Siliwończuk




Many years geological studies carried out by the Geological Institute, other research centers, and by the Geological Enterprise to study the natural broken stone deposits not only contributed to the present knowledge of economic reserves but also served to define guide-lines for further exploration.
The main natural broken stone base includes chiefly Quaternary clastic deposits: glacial, fluvioglacial, fluvial, and those deposited on the Baltic floor. The biggest and richest broken stone deposits are found .in the valleys of the Sudetic and Carpathian streams (52 per cent of the recognized reserve base).
The occurrence of clastic deposits related to the action of the Scandinavian glaciers is controlled by the stratigraphy and the preservation degree of morphogenetic forms. Particularly favourable conditions have been found to exist in the accumulation area of the Pomerania phase of the North Polish glaciation and of the North Mazovia stade (the eastern portion) of the Middle Polish glaciation. In the remainder of the country only minor individual deposits are found.
In addition, gravel-sandy deposits. resting on the Baltic floor to the depth of 40 meters represent considerable reserves of raw materials.
A vital problem, so far not considered, is the utilization of erratic boulders accumulated in the boulder field.
The grain size distribution of the Quaternary clastic deposits is very diversified.
In the stream valleys gravel and gravel-sandy deposits predominate, their percentage of fraction up to 2.5 mm being from 12 to 40. In the glacial and fluvioglacial deposits as well as those occurring in stream valleys in the lowlands the content of grain fraction up to 2.5 mm is relatively high – from 45 to 60%.
The petrographic composition of the deposits discussed shows both regional variability resulting !from the diversity of rocks from the provenance areas and local variability due to sorting in the course of transportation. Igneous rocks (38–42% in average) predominate among the material of the glacial and fluvioglacial clastic deposits. In the Sudetic area grains of quartz, crystalline rocks, and quartzite are the main constituents, while in the Carpathian deposits: fragments of flysch sandstone previal.
The broken stone industry expected to cover the demands of broken stone for construction purposes should strive at a more rational utilization of their raw material base. In this respect a unified development programmed for areas with high concentration of deposits and a full utilization of all fractions of the deposit are a crucial problem. Thus major importance should be attached to registration and supervision of the broken stone producing units.


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