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Provenance of heavy minerals to the Middle and Upper Jurassic epicontinental deposits of NW Poland

Bembenek Kinga, Woronko Barbara, Ziółkowski Piotr

Geological Quarterly

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2021

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Vol. 65, No. 1

art. no. 2

EN

The source of clastic material supplied to the epicontinental sea during the Middle and Late Jurassic in the Pomeranian Segment of the northern part of the Mid-Polish Trough is analysed, using deposits from the Rzeczyn PIG-1 borehole that represent the Łyna, Chociwel, Brda, Pałuki, Kcynia and Rogoźno formations. Heavy mineral analysis, including weathering indices (ZTR, GZI, RZI and Q) and standardised scores for each mineral species, shows that each formation is characterized by a different heavy minerals association. In each association, transparent minerals include both ultrastable minerals (zircon, tourmaline and rutile), occurring in various proportions, and unstable minerals. This indicates that deposits subject to earlier multiple reworking were eroded from the surrounding landmasses. Most probably these deposits represented Triassic rocks, although fresh weathering covers were also eroded. The main direction of clastic material supply was from the N and NW, and to a lesser degree from the NE. The main reasons for changes in the source areas were probably sea level oscillations, while during regressions, exposed parts of the seabed became source areas of clastic material. Conversely, during transgressions, parts of the seabed became cut off from the supply of clastic material from eroded landmasses.

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Zastosowanie metody statycznego sondowania w analizie genezy osadów, na przykładzie sandru Gwdy

Paluszkiewicz R., Paluszkiewicz R., Wierzbicki J.

Landform Analysis

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2010

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Vol. 13

83-89

PL

Przekonsolidowania serii piaszczysto-żwirowych sandru Gwdy-Piławy. Analiza statystyczna wyników prac umożliwiła podział serii glacifluwialnych na trzy grupy, a co za tym idzie umożliwiłą wyznaczenie trzech etapów depozycji serii sandrowych.

EN

The paper presents the new possibilities of use the CPTU (Static Cone Pentration Test) results for the purpose of the stratygraphic analysis. On the basis of the CPTU results the overconsolidation ratio (OCR) has been computed along profile of investigated glaciofluvial deposits of Gwda-Pilawa outwash plain. The statistical analysis of the results allowed to divide the over 15 m of glaciofluvial series into 3 parts, which represent different stages of the outwash plain existence.

3

Sequence stratigraphy of Carboniferous paralic deposits in the Lublin Basin (SE Poland)

Waksmundzka M.

Acta Geologica Polonica

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2010

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Vol. 60, no. 4

557-597

EN

Based on lithofacies analysis of clastic, clay and carbonate rocks, wireline logs and sequence stratigraphy, sixteen depositional sequences have been distinguished in the paralic Carboniferous succession of the Lublin Basin from the Visean to the base of Westphalian B. The facies evolution and depositional architecture of the deposits belonging to three types of depositional systems tracts, i.e. lowstand (LST), transgressive (TST) and highstand (HST) have been reconstructed. The sequences are bounded by type 1 basal unconformities formed during subaerial erosion following relative sea-level fall and lowstand. This erosion, that in some cases reached down to the LST deposits of the underlying sequences, mainly affected the HST deposits. Relative sea-level rise controlling the base level of the rivers during lowstand was the basic factor influencing facies development, cyclicity and thickness of fluvial deposits, as well as the vertical and lateral transformation of rivers in theparalic Carboniferous succession. Vertical transition of high- to low-energy fluvial environments can be observed within the LST. The LST deposits typically occur in incised shelf valleys and in non-incised fluvial systems. Within the LST of sequences 2 and 4 to 10 commonly occur medium and large systems of simple incised valleys that developed in a coastal-plain system. The LST of sequences 11 to 15 comprises large systems of compound incised valleys that developed in a piedmont system. Relative sealevel rise in the late lowstand, sea-level oscillations during transgression and highstand and the volume of sediment supply were the main factors influencing facies development, cyclicity, thickness and lateral distribution of the deltaic deposits, shallow-shelf shales and limestones. Within the TST commonly occur coarsening-upward and non-gradational cyclothems that correspond to parasequences and were formed in the distal parts of the inner-shelf delta lobes. In the HST, the most commontypes are coarsening-upward cyclothems developed during the progradation of innershelf delta lobes and small lake deltas, as well as non-gradational cyclothems formed in lakes on a delta plain without influence of delta lobes. The transgression of sequence 7 probably had the widest extent of all the sequences in the paralic Carboniferous succession of the Lublin Basin. It was presumably much wider to the N, NE and NW than the presently accepted boundaries of the basin. Based on analysis of three curves of relative sea-level changes in the paralic Carboniferous succession of the Lublin Basin and the transgressive-regressive curve for the Carboniferous of Western Europe, the sequences distinguished have been correlated with the chronostratigraphic scheme for the Carboniferous System. The diachronous commencement of sedimentation has been confirmed and evaluated. The lack of deposits of sequence 5 in the eastern part of the basin suggests the presence of a stratigraphicgap encompassing the upper Brigantian. The position and range of stratigraphic gaps present elsewhere in the basin has also been indicated. In the north-westernmost and easternmost parts of the study area the gap has the widest range, encompassing the upper Arnsbergian to lower Marsdenian strata. The mid-Carboniferous boundary between the Mississippian and Pennsylvanian has been located at the base of sequence 8.

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The Ordovician-Silurian boundary beds between Saaremaa and Gotland, Baltic Sea, based on high resolution seismic data

Tuuling I., Flodén T.

Geological Quarterly

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2007

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Vol. 51, No 3

217-229

EN

New seismic profiles have been used to revise earlier interpretations of the Ordovician-Silurian bound ary beds be tween Saaremaa and Gotland. Atrans-Baltic reflector with erosional fea ures (S2) above the erosional Ordo vician-Silurian boundary reflector (S1) correlates with the bound ary between the Raikküla and Adavere stages. The sporadic reflector or2 below the S1 reflector off shore from Gotland represents the erosional boundary between the Pirgu and Porkuni stages. Three stratigraphic gaps occur in the Ordovician-Silurian boundary beds off shore from Gotland. The amount of eroded rocks between the Pirgu and Porkuni stages, the Ordovician and Silurian systems and the Raikküla and Adavere stages can change rapidly. Consequently, the thick ness and stratigraphy of the Ordovician-Silurian boundary beds around Gotland can change considerably across short distances. The O4-5-S1 unit off shore from Gotland, including carbonate build ups and erosional incisions infilled with Porkuni strata, belongs facially to the transi ional belt between the Estonian Shelf and the Livonian Tongue. The thick ness changes in the S1-S2 unit (Juuru and Raikküla stages) indicate an extensive subma rine erosional channel, streching from north of Estonia across the Baltic Sea and central Gotland, which developed in the Baltic Basin along a shelf to deep-basin transect dur ng Llandovery time.