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Analiza sumarycznych rozkładów gęstości prawdopodobieństwa (PDFs) dat radiowęglowych i luminescencyjnych z nieciągłych profili osadów rzecznych na tle zmian klimatycznych zapisanych w rdzeniu NGRIP

Michczyńska Danuta J., Dzieduszyńska Danuta A., Gębica Piotr, Krzyszkowski Dariusz, Ludwikowska-Kędzia Małgorzata, Petera-Zganiacz Joanna, Wachecka-Kotkowska Lucyna, Wieczorek Dariusz

Przegląd Geologiczny

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2023

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Vol. 71, nr 10

527--529

EN

The study presents the results of a compre¬hensive analysis of radiocarbon and luminescence dates from samples taken from a fluvial environment for selected regions south of the LGM line, presented against a high-resolution INTIMATE stratigraphy. It is shown that discontinuous records of fluvial environmen¬tal responses in such an analysis reveal significantly more details than studies conducted at individual sites. A strong correlation is observed between peaks in the PDF curves of radiocarbon dates and interstadial periods, while accumulations of luminescence dates are corre¬lated with stadial periods.

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Facies and statistical analyses of a crevasse-splay complex at the Tomisławice opencast lignite mine in central Poland

Dziamara Mariusz, Kaczmarek Paweł, Klęsk Jakub, Wachocki Robert, Widera Marek

Geologos

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2023

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Vol. 29, No. 3

173--181

EN

The studied crevasse-splay complex, situated within the 1st Mid-Polish lignite seam (MPLS-1), ranks amongst the best-developed and most readily accessible for direct research of all hard coal and lignite occurrences worldwide. The sandy-coaly sediments constituting it required a number of field and laboratory tests. However, the present article focuses solely on sedimentological and statistical analyses of sediments along a selected key section, the most important results of which are presented below. First of all, data obtained in previous sedimentological studies have been confirmed, in that individual segments of this complex represent both subaerial and subaqueous types of crevasse splays. On the one hand, their sediments are characterised by an extremely high content of coalified organic matter, reaching 20–40 wt.% in some samples; on the other, these crevasse splays are composed of fine sands with a median and mean grain size of 0.15 mm. In addition, the remaining statistical parameters (standard deviation, skewness and kurtosis) indicate a very good sorting of these sands, no significant so-called ‘tails’ and a better sorting close to the sediment mean grain size value, respectively.

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Ancient and modern anastomosing rivers: insights from sedimentological and geomorphological case studies of the Triassic, Neogene and Holocene of Poland

Kędzior Artur, Widera Marek, Zieliński Tomasz

Geological Quarterly

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2021

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Vol. 65, No. 4

art. no. 54

EN

We review the three regional anastomosing fluvial systems, both ancient and modern. The dinosaur-bearing upper Triassic succession in Krasiejów (S Poland) is composed of siltstones and claystones that are divided into three facies associations. One of the fluvial associations is characterized by features typical of a low-energy anastomosing river system in a tropical semiarid climate, interpreted as the result of accumulation in deep, wide and low-sinuosity palaeochannels with pronounced vertical accretion. Deposition from suspension predominated in flows of very low stream power. The upper Neogene muddy succession in a tectonically active area (Kleczew Graben, central Poland) includes a great number of fluvial palaeochannels filled with sand and/or mud. These ribbon-shaped fluvial bodies are deep and wide, and represent channels showing very lim ited lateral migration. They were filled mostly under low-energy condi tions, and their mapped course shows an “anabranching” pattern in plan view. The palaeochannels are transitional from sand- to mud-dominated. The Holocene upper Narew River (NE Poland) represents a modern anastomosing fluvial system. The interconnected channels form an anabranching pattern. The channels are straight to slightly sinuous, relatively deep and wide. Interchannel, low-lying “islands” are covered by peat-forming plants. Despite the low stream power, in-channel deposition is dominated by sand transported as bedload. The channel banks are stabilised by vegetation, which effectively prevents their lateral migration.

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Osady glifu krewasowego z miocenu Polski środkowej w okolicach Konina

Widera M., Chomiak L., Gradecki D., Wachocki R.

Przegląd Geologiczny

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2017

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Vol. 65, nr 4

251--258

EN

The paper presents results of a study of crevasse splay deposits from the Miocene of central Poland near Konin. These mineral deposits occur within the 1st Middle-Polish lignite seam of Middle Miocene age, which is exploited from the Tomislawice lignite opencast mine. They consist of fine-grained sands with an admixture of plant detritus at the top and bottom layers, where the muddy-sandy clasts are present. The investigated crevasse splay deposits are predominantly massive or horizontally stratified, and they occasionally reveal small- to large-scale (planar, trough and ripple) cross-stratification. Thus, they are interpreted as representing dense gravity flows, sheet flows, and channelized flows of variable energy. The crevasse splay was formed subaerially during sudden flood conditions on the floodplain covered by a low-lying mire with predominant herbaceous vegetation. The description of the crevasse splay deposits from the Miocene of central Poland can be helpful in better understanding the sedimentation conditions of relatively thick lignite seams.

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Fluvial sedimentation of sandy deposits of the Słupiec Formation (Middle Rotliegendes) near Nowa Ruda (Intra-Sudetic Basin, SW Poland)

Kurowski L.

Geologia Sudetica

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2004

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Vol. 36

21-38

EN

The sandy sediments described in this paper are the lower, approximately 400-meter-thick part of the Słupiec Formation, which is part of lower Permian clastic deposits in the Intra-Sudetic Basin. At their base, the sandy deposits of the Słupiec Formation are bounded by fine-grained lacustrine sediments known as the Upper Anthracosia Shale (Krajanów Formation); upwards, they pass into the Walchia Shale (the upper part of the Słupiec Formation), also regarded to be of lacustrine origin. These sandstones consist chiefly of sublithic to subarkosic arenites and wackes. In places, polymictic conglomerates and fine-grained sediments, and also sublithic to subarkosic mudstones occur. These sediments form a structurally varied facies assembly, presumably fluvial in origin. An analysis of the vertical sequence of lithofacies revealed a distinct tendency towards the formation of simple cyclical sequences with the grain fining upwards and with a distinctly expressed asymmetry in favour of 'high-energy' medium- and coarse-grained facies. The oscillation tendency was marked only in 'low-energy' fine facies, which are sparsely represented in the sequence. The paleochannel analysis yielded results compatible with the outcome of the lithofacies analysis. The paleochannels are very shallow in relation to their width, and have a planar, erosional bottom configuration, and in places a terrace bank morphology. The fluvial system features described here may indicate a terminal fan environment as the possible depositional location place of the Słupiec Formation sandy sediments. The source areas were located at the S and SE margins of the Intra-Sudetic Basin, and the flow was towards the W and NW towards its centre, to shallow inland basins, probably of a playa type. The red colour of the sediments may be indicative of arid or semi-arid climatic conditions in this environment during the Middle Rotliegendes .