Z morfologii głębokorówni bałtyckiej w granicach arkusza Puck

Radosław Pikies

Abstract


Na podstawie analizy echogramów w SW części Basenu Gdańskiego wyróżniono 3 główne typy rzeźby powierzchni dna morskiego: falistą, płaską lub lekko falistą oraz równiny kotlin podwodnych. Obszar dna o rzeźbie falistej stanowi najstarszą część powierzchni dennej zbudowaną z glin lodowcowych o barwie brunatnobrązowej. Najmłodsze są części dna równin kotlin podwodnych wypełnione osadami akumulacji współczesnej. Stwierdzono analogię z rzeźbą dna Basenu Zachodniobornholmskiego.

ON MORPHOLOGY OF BALTIC DEEP FLAT IN THE PUCK SHEET

The paper presents new data on morphology of seafloor in SW part of the Gdańsk Basin. The studied area represents deep part of seafloor in the Southern Baltic, so called deep flat (Figs 1, 2).

In the studied deep flat, three major types of seafloor relief were differentiated (Fig. 3): 1 –seafloor surface with wavy relief, 2 - seafloor surface with flat or somewhat wavy relief, 3 - flats of subaqueous depressions.

The area with wavy relief is the oldest, i.e. with morphology most early formed. It is characterized by the presence of deposits related to glacial accumulation – tawny-brown tills. An area similar in morphological development and with hilly relief is built of tills and residual sandy-gravel deposits. Seafloor areas characterized by wavy relief look like inliers of an older bedrock (which forms original glacial landscape), the highest elements of which are exposed only (Fig. 4).

The morphology of seafloor areas characterized by flat or somewhat wavy relief originated later. Such relief is abrasional in origin which is indicated by the presence of V-shaped depressions, presumably representing lower parts of strongly diversified relief. the higher elements of which became almost completely eroded.

The flat of subaqueous depressions is the youngest, i.e. with morphology most lately formed. Its present shape is the result of the present-day accumulation of marine sediments (Fig. 6).

The obtained results and the accepted concept of genetic development of relief in the deep flat are in several points consistent with the results of studies in the West Bornholm Basin by F.C. Kögler and B. Larsen (1979) and they agree with those on structure of the Gdańsk Deep, recently obtained by F.C. Kögler and others (1980).


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DOI: https://doi.org/10.7306/gq.v25i4.9046