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Integrated magnetotelluric and seismic investigation of Cenozoic graben structure near Obrzycko, Poland

Cygal Adam, Stefaniuk Michał, Kret Anna

Acta Geophysica

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2021

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Vol. 69, no. 2

711--723

EN

This article presents the results of an integrated interpretation of measurements made using Audio-Magnetotellurics and Seismic Refection geophysical methods. The obtained results were used to build an integrated geophysical model of shal low subsurface cover consisting of Cenozoic deposits, which then formed the basis for a detailed lithological and tectonic interpretation of deeper Mesozoic sediments. Such shallow covers, consisting mainly of glacial Pleistocene deposits, are typical for central and northern Poland. This investigation concentrated on delineating the accurate geometry of Obrzycko Cenozoic graben structure flled with loose deposits, as it was of great importance to the acquisition, processing and interpretation of seismic data that was to reveal the tectonic structure of the Cretaceous and Jurassic sediments which underly the study area. Previously, some problems with estimation of seismic static corrections over similar grabens flled with more recent, low-velocity deposits were encountered. Therefore, a novel approach to estimating the exact thickness of such shallow cover consisting of low-velocity deposits was applied in the presented investigation. The study shows that some alternative geophysical data sets (such as magnetotellurics) can be used to signifcantly improve the imaging of geological structure in areas where seismic data are very distorted or too noisy to be used alone

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The maximum ice sheet extent and its retreat in the western part of the Holy Cross Mountains, Poland, during the Sanian 2 Glaciation/MIS 12 based on geological data and analysis of karst phenomena

Dzierżek Jan, Lindner Leszek, Cabalski Krzysztof, Urban Jan, Cyglicki Michał

Acta Geologica Polonica

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2021

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Vol. 71, no. 2

199--218

EN

The paper is focused on the palaeographic development of the western part of the Holy Cross Mountains, Poland, during the maximum extent of the Sanian 2 (MIS 12) ice sheet and its retreat. The studies were based on archival cartographic data, coupled with new lithological and petrographic analyses of limni- and fluvioglacial sands, i.e., grain-size composition, quartz grain morphology and heavy mineral analysis, as well as analysis of the erratic material of tills. The results confirm the regional variability of the erratic material in the Sanian 2 tills and point to the long-term development of fluvioglacial sands cover documenting cold climate conditions. They also evidence that the western part of the Holy Cross Mountains was the area where two oppositely directed ice sheet lobes (Radoszyce and Sandomierz) advanced during the Sanian 2 Glaciation and that deglaciation of the area took place in two stages. Huge quantities of meltwater released at that time contributed to the intensification of earlier initiated karst phenomena, as well as filling of the existing caves by fluvioglacial sands.

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The evolution of a Weichselian proglacial lake in NW Poland as revealed by static penetration tests

Wierzbicki Jędrzej, Paluszkiewicz Renata, Paluszkiewicz Ryszard

Geologos

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2011

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Vol. 17, No. 2

111--119

EN

The lithology, structure and geophysical characteristics of the glaciolacustrine clays deposited in the Wierzchowo proglacial lake were determined using static penetration tests (CPTU) in combination with standard lithological measurements. The deposits are divided into four lithological units (R1 to R4) on the basis of overconsolidation. Units R3 and R4 are separated by mass-flow deposits. The depositional conditions history of the lake result represent four phases: (1) an initial (low-energy) phase with the deposition of the rhythmically laminated sediments of units R1 and R2, which are divided by an erosional interval; (2) a phase of non-deposition with some desiccation structures and extended consolidation of sediments; (3) the main phase characterised by deposition of the rhythmically laminated sediments of unit R3; and finally, (4) the youngest phase, which represents alternations of deposition and erosion. The results show that sedimentation in the Wierzchowo proglacial lake was less continuous, and that the depositional processes were more complex than in the neighboring Złocieniec glacial lake.

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Obszary macierzyste skandynawskich eratyków przewodnich osadów ostatniego zlodowacenia północno-zachodniej Polski i północno-wschodnich Niemiec

Górska-Zabielska Maria

Geologos

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2008

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Vol. 14, No. 2

177--194

PL

Wychodnie skalne środkowego Bałtyku, wysp szwedzkich oraz południowo-wschodniej Szwecji były obszarem dominującej egzaracji tej części lądolodu, która podczas fazy pomorskiej późnego plenivistulianu dotarła po NW Polskę i NE Niemcy. W zespole wszystkich skandynawskich narzutniaków najmłodszych osadów depozycji glacjalnej z NW Polski i NE Niemiec około 30-40% stanowią skały krystaliczne. Ich obszarem macierzystym jest tarcza bałtycka, uformowana w proterozoiku. Do najważniejszych narzutniaków pochodzących z tarczy bałtyckiej należą: granity Uppsala i Stockholm, granit rapakivi Aland, eratyki z Dalarny (granity Garberg, Jima, Siljan oraz porfir Dalama). Są to także eratyki egzarowane w transskandynawskim paśmie magmowym: granity Smáland, Vánevik, Vörlebo, Filipstad, Kristinehamn, czerwone i szare granity Vöxjö, porfiry Páscallavik; dalej są to eratyki z regionu Blekinge-Bornholn (granity Karlshamn, Spinkamála, Halen, Vánga, Hammer, Vang, Svaneke) oraz eratyki z regionu gnejsowego SW Szwecji (sjenity Glimákra i Vaggeryd, gnejs Járna i czarnokit Varberg). W grupie skał narzutowych są także skały uformowane podczas młodszych zdarzeń geologicznych (np. permski porfir rombowy z Oslo czy jurajski bazalt ze Skanii). Skały macierzyste są zlokalizowane również w obrębie pokrywy osadowej dna Bałtyku centralnego i południowego, której powstanie wiąże się ze zdarzeniami geologicznymi w neoproterozoiku, wczesnym paleozoiku i kredzie. Z dna Bałtyku, wysp Gotlandii i Olandii oraz państw nadbałtyckich pochodzi około 60-70% wszystkich eratyków osadowych późnoplenivistuliańskiej depozycji glacjalnej. Są to: piaskowce jotnickie, wapienie ordowiku i syluru, dewońskie piaskowce i dolomity. Z południowo-zachodniego Bałtyku pochodzą górnokredowe wapienie oraz górnokredowe i paleogeńskie krzemienie.

EN

The hardrock substratum of the middle Baltic Sea, Swedish islands and south-eastern Sweden are the main areas eroded by the late Pleniweichselian ice sheet. The erratics that the ice transported away from these areas are now found in the youngest glacial deposits of NW Poland and NE Germany. The Scandinavian erratics sampled from the youngest glacial deposits in NW Poland and NE Germany consist for 30-40% of crystalline rocks derived from the Proterozoic of the Fennoscandian (Baltic) Shield. They include Svecofennian rocks (Uppsala granite, Stockholm granite, Áland rapakivi granite), granites and porphyries from Dalama (Garberg granite, Jima granite, Siljan granite, Dalama porhyry), as well as materiał from the Transscandinavian Igneous Belt (Smáland granite, Vánevik granite, Vörlebo granite, red and grey Vöxjö granites, Páscallavik porphyry, Filipstad granite and Kristinehamn granite), from the Blekinge-Bornholn region (Karlshamn granite, Spinkamála granite, Halen granite, Vánga granite, Hammer granite, Vang granite, Svaneke granite), and the gneissic region of SW Sweden (Glimákra syenite, Vaggeryd syenite, Járna gneiss, Varberg chamockit). Other erratics come from younger volcanic rocks, dating back to the Late Palaeozoic and Jurassic/Cretaceous (e.g., the romb porphyry from the Oslo graben and Scanian basalt). The sedimentary cover of the Neoproterozoic, the Lower Palaeozoic and the Cretaceous (from the Baltic Sea, Aland Islands, Gotland, Öland and the Baltic states) are also source rocks. Glacial sediments deposited directly south of the Baltic Sea consist for 60-70% of Fennoscandian sedimentary erratics. They include: Jotnian sandstones, Ordovician and Silurian limestones, Devonian sandstones (Old Red) and dolomites. Other source areas of indicator erratics are located along the Sorgenfrei-Teisseyre-Tornquist zone and further to the south-west (e.g. Late Cretaceous limestones, Late Cretaceous and Paleogene flints).

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Osady deglacjacyjne zlodowacenia Warty we wschodniej części regionu łódzkiego

Rdzany Z.

Przegląd Geologiczny

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2006

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Vol. 54, nr 4

343-351

EN

The author attempts at formulating a synthetic description of geological and geomorphological effects of theWartanian ice-sheet deglaciation in the eastern part of the Łódź region, taking their spatial variability into consideration. Characteristic features of Wartanian Glaciation sediments occur in this area, and their lithofacial diversity and spatial distribution needed interpretation. The deposits document the complex processes of deglaciation, which developed here across an unusually broad area in the scale of the Polish Lowland. The best developed deglaciation sediments occur in the eastern part of the Łódź Heights, between the Mroga and Rawka rivers, as structural components of different types of kames and glaciofluvial covers. In locations where glacial till is elevated they include mainly sediments of braided rivers and alluvial cones, whereas in areas of wide depressions of till and, thus, of the ice-sheet bedrock — glaciolimnic sediments prevail. The highest and most diverse western part of the Łódź Heights is characterised by the occurrence of thin and discontinuous deglaciation sediments, because this area was shaped mainly during the ice-sheet transgression. During deglaciation, ablation waters left mainly traces of erosion, whereas the glaciofluvial accumulation series are not well developed. In the Rawa Interfluve, deglaciation sediments accumulated predominantly at the early deglaciation stage in sparesely distributed broad basins of kame sedimentation. In the Piotrków Plain, deglaciation deposits are thin; ice-sheet disintegration proceeded without major blockages of ablation waters, resulting in a less diverse interfluvial landscape.

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Eratyki przewodnie w glinach morenowych Polski

Czubla P., Gałązka D., Górska M.

Przegląd Geologiczny

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2006

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Vol. 54, nr 4

352-362

EN

Erratics analysis is one of the principal methods used to study glacial sediments. Usually, simplified petrography of gravel fraction is employed, whereas more advanced techniques, based on interpreting certain rock types of Fennoscandian provenience, are still rarely used in Poland. This is mainly due to the lack of training in classifying erratic rocks, what in turn is at least partly a consequence of the lack of appropriate Polish language atlases. We are willing to bridge this gap, presenting the 33 descriptions of the indicator rock types found in the Pleistocene sediments in Poland. Most descriptions have been illustrated with colour photographs, showing either the specimens from Poland, or the ones collected during our expeditions to Sweden, Denmark and Finland.We present the most important features, which allow to both identify a sample unambiguously and to tie it to a specific outcrop in Fennoscandia. Additionally, we include the geographic coordinates of the central points of source outcrops, used to define the theoretical pebble centres position (Lüttig 1958).

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Sediment texture in contemporary glacial environment - examples from Hansbreen, southern Spitsbergen

Karczewski Andrzej, Rachlewicz Grzegorz, Szczuciński Witol

Geologos

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2003

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Vol. 6

111--132

EN

The sediment texture data (grain size, quartz grain abrasion, and roundness) from a range of different glacial environments at Hansbreen in southern Spitsbergen are presented. The six main sediment groups were distinguished: subglacial till, supraglacial debris cover, debris flow deposits, supra- and englacial meltwater stream deposits, dirt cone and proglacial glaciofluvial deposits. The division is supported by grain size statistics (presented in form of 3D diagrams), and is also legible in quartz grain abrasion differences. The latter one reveals strong changeability depending on the grain size class. No correlation between clay ratio and standard deviation vs. quartz grain abrasion was found. Lithology has limited impact on clast roundness (analysed for > 2.8 mm fraction), although restricted by short distance and time of transportation. A comparison with similar data set from Werenskioldbreen shows the deposits of Hansbreen as more mature, which is probably caused by reworking of older deposits and longer transport.

PL

Wybrane cechy teksturalne osadów (rozkład uziarnienia, abrazja ziarna kwarcowego - grainformametria mechaniczna i obtoczenie) zostały określone dla prób z różnych środowisk glacjalnych lodowca Hansa (Hansbreen), południowy Spitsbergen. Wyróżniono 6 podstawowych grup osadów: osady subglacjalane, pokryw supraglacjalnych, osady spływów błotnych, stożków ablacyjnych, supra- i inglacjalnych potoków wód roztopowych oraz proglacjalnych osadów fluwioglacjalnych. Podział ten znalazł swoje odzwierciedlenie w analizie statystycznych wskaźników uziarnienia (prezentowanych w postaci diagramów 3D) i jest również czytelny w zróżnicowaniu abrazji ziarna kwarcowego. Ta ostatnia wykazuje zróżnicowanie w zależności od wielkości frakcji. Nie wykryto wyraźnej relacji pomiędzy wskaźnikiem ilastości oraz odchyleniem standardowym a wskaźnikami obtoczenia. Litologia ma ograniczony wpływ na obtoczenie (analizowana frakcja > 2,8 mm). Porównanie z podobnym zestawem danych dla lodowca Werenskiolda (Werenskioldbreen) wskazuje na większą dojrzałość osadów lodowca Hansa, prawdopodobnie można to wiązać z redepozycją starszych osadów i dłuższym transportem.