Charakterystyka petrograficzna utworów karbonu południowej części niecki warszawskiej

Małgorzata Połońska

Abstract


Wykonano analizę petrograficzną skał karbonu podłoża niecki warszawskiej z otworów Nadarzyn IG 1 i Mszczonów IG 2. Wydzielono dwie podstawie serie skał: w części przyspągowej o przewadze materiału wulkanoklastycznego a powyżej - osadowego. Wykazano, że materiał detrytyczny pochodzi z różnych obszarów źródłowych. Przeprowadzono interpretację warunków sedymentacji karbonu na tym terenie.

PETROGRAPIDC CHARACTERISTICS OF CARBONIFEROUS ROCKS OF SOUTHERN PART OF THE WARSAW BASIN

The paper presents petrographic characteristics of Carboniferous rocks a the basement of the Warsaw Basin, based on data from the boieholes Nadarzyn IG I and Mszczonów IG 2 These rocks are represented by volcanoclastic deposits at the base and sedimentary complex above. At Mszczonów, there were recorded conglomerates and tuffaceous sandstones representing lithofacies equivalents of tuffites from Nadarzyn. They are mainly composed of debris a intrusive rocks and pyrogenic material sedimentary rocks predominate in both parts of the Carboniferous section. They are built of mono- and polycrystalline quartz grains, rock debris somewhat different in composition from that of the volcanoclastic series, alkaline feldspars and micaceous minerals, mostly biotite. Cement of rocks from Mszczonów consists a cIay-siliceous-chlorite matter, whereas that from Nadarzyn is very rich in kaolinite and ferruginous-coaIly matter. Medium- and very finely grained sandstones predominating at Nadarzyn were assigned to quartz wackes and lithic graywackes Fine-grained sandstones from Mszczonów comprise both wackes and quartz arenites. Petrographic data made possible to establish differences related to somewhat different sedimentary conditions in the Carboniferous in this area. The early stage of sedimentation was characterized by volcanic activity of the acid type. The volcanic material was coming from a center situated in western part of that area In the vicinities of Mszczon6w, the volcanic activity was accompanied by some marine influep.ces. This was followed by change in sedimentary conditions, presumably related to tectonic movements. Swamps and peatbogs originated in the Nadarzyn area and detrital material related to destruction of rocks of other type was presumably coming from the direction of the Precambrian Platform.


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