Badania litostratygraficzne utworów wyższego silezu w okolicach Głuszycy (depresja śródsudecka)

Jerzy B. Miecznik

Abstract


Opracowano nowy, nieformalny podział litostratygraficzny utworów wyższego silezu środkowej części NE skrzydła depresji śródsudeckiej. Wyróżniono trzy wyraźnie odrębne serie skał, odpowiadające cyklom sedymentacyjnym. Dolna seria (A) obejmuje warstwy żaclerskie górne i niższą część warstw glinickich, seria środkowa (B) - wyższą część warstw glinickich, górna zaś odpowiada warstwom ludwikowickim. Między serią B a warstwami ludwikowickimi stwierdzono niezgodność erozyjną wiązaną z fazą intrastefańską. Opracowany profil skorelowano z profilem utworów wyższego silezu SW (czeskiego) skrzydła depresji śródsudeckiej.

LITHOSTRATIGRAPHIC STUDIES ON UPPER SILESIAN ROCKS IN THE VICINITIES OF GŁUSZYCA (INTRA-SUDETIC DEPRESSION)

Continental Silesian and Lower Permian rocks occurring in the vicinities of Głuszyca represent a part of north-eastern limb of the Intra-Sudetic Depression.

Permo-Carboniferous rocks of that unit are characterized by high variability in Iithofacies and thickness which, along with scarcity or even the lack of fossils in some parts of the section result in serious drawbacks for stratigraphic studies. One of more significant but still open problems is connected with establishing stratigraphy of the Upper Silesian in Polish part of the Intra-Sudetic Depression. According to the present author, the Upper Silesian comprises rocks occurring above typically developed Žacléř Beds (Westphalian A and B). Boreholes recently made by the Geological Institute in the vicinities of Głuszyca supplied some new data, making possible reinterpretation of the Upper Silesian in that Depression.

The studies showed the presence of a differentiated sequence in the Głuszyca area. Within the sequence, there may be recognized three clearly separate series of deposits. corresponding to sedimentary megacycles.

A lower series (A) is primarily represented by red-coloured siltstone-sandstone deposits. Its lower part is characterized by varying share of coarse-detrital deposits. The series. underlain by coal-bearing Žacléř Beds. corresponds to Upper Žacléř Beds and lower part of the Glinik Beds.

The middle series (B) is represented by coarse-detrital rocks. characterized by marked share of volcanic material. A member of coal-bearing rocks occurs in- its top part. The coarse-detrital rocks are gray pinky or red in colour. Deposits of that series correspond to upper part of the Glinik Beds.

The-upper series; discordantly overlaying the series B, comprises conglomeratic-sandstone rocks with siltstone intercalations. At Głuszyca Górna, the deposits pass upwards into finer-grained. Rocks of that series are usuaIly red-coloured and they correspond to the Ludwikowice Beds.

The lithostratigraphic section of the Upper Silesian may be easily correlated with that in south-western (Bohemian) limb of the Intra-Sudetic Depression. Basal part of the series A represents an equivalent of the Petrovice Member, and the remaining part - an equivalent of the Svatoňovice Member. The series B corresponds to the Jivka Member, and the Ludwikowice Beds (upper series) may be correlated with the Vernéřovice Member.

The above lithostratigraphic correlation is supported by the results of biostratigraphic studies on the borehole column Głuszyca Górna IG 1, carried out by J. Jerzykiewicz (fide K. Augustyniak, 1977).

The recorded discordance between the series B and Ludwikowice Beds may be explained by movements related to the intra-Stephanian phase. During that phase, upper part of deposits of the series B was subjected to erosion. The erosion was especially intense in NW part of the Głuszyca area, where coal-bearing deposits are missing.


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