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Verification of the seismic P‑wave velocities under Moho boundary: Central Poland case study, LUMP profile

Dec Monika, Polkowski Marcin, Janik Tomasz, Stec Krystyna, Grad Marek

Acta Geophysica

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2019

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Vol. 67, no. 1

41--57

EN

The tectonic settings investigated by several seismic projects in previous research targeting the structure in Central Poland mainly focused on the Earth’s crust. In this paper, we present P-wave velocity verification in the uppermost mantle beneath LUMP profile towards SSE-NNW. Using recordings of 36 DATA-CUBE recorders from ca. 300–490 km far earthquake in coal mine “Janina” in southern Poland, we calculated travel times to verify P-wave velocity below the Moho boundary from previous studies. It shows that a significantly lower mean velocity value should be used for the upper mantle while counting these offsets of travel times in the SSE-NNW direction than that used on previous profiles. We present two possible models: first, the most simple one that fits the observed first arrivals, and the second with a low-velocity layer beneath the Moho boundary. In both cases, we used a priori crustal model focusing only on P-wave velocity in the uppermost mantle. Both of them significantly improved adjustment of travel times to the observed data. To evaluate the tendency of adopting too high velocities beneath the Moho, we used also 11 broadband stations, Reftek 151-121 “Observer”, from “13 BB Star” passive experiment and 6 STS-2 seismometers from permanent stations of the Polish Seismological Network (PLSN).

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The Tithonian Chitinoidellidae and other microfossils from Owadów–Brzezinki quarry (central Poland)

Pszczółkowski A.

Volumina Jurassica

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2016

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Vol. 14, no. 1

133--144

EN

Tithonian (= “Middle Volgian”) carbonate rocks are exposed in Owadów-Brzezinki quarry 19 km southeast of Tomaszów Ma-zowiecki, central Poland. In the upper part of the Sławno Limestone Member, chitinoidellids have been identified in thin sections from three samples, only. Therefore, the documented part of the Chitinoidella Zone in Owadów-Brzezinki quarry is about 0.3 m thick. The identified chitinoidellid taxa suggest that this assemblage represents the Upper Tithonian Boneti Subzone. The Chitinoidella Zone occurs at the top of Unit I and correlates with the uppermost interval of the Zarajskensis Horizon (Matyja, Wierzbowski, 2016). Other microfossils identified in the Chitinoidella Zone consist of Saccocoma sp. and benthic foraminifera of the genus Planularia. Calcareous dinoflagellate cysts (Cadosina semiradiata semiradiata Wanner and C. cf. semiradiata semiradiata Wanner) occur above the chitinoidellid assemblage, in the strata corresponding to the Gerassimovi Subzone of the Virgatus Zone (Matyja, Wierzbowski, 2016). Calcareous nannofossils are extremely rare in the thin sections studied; only one small specimen was seen, identified as Rhombolithion minutum (Rood et al., 1971) Young et Bown 2014. In contrast, microbial filaments are frequently observed in the studied thin sections. Their shape and pattern are reminiscent of some recent Cyanobacteria of the order Nostocales, however the Tithonian microbial filaments are much thinner.

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Stability conditions of the Vistula Valley attained by a multivariate approach – a case study from the Warsaw Southern Ring Road

Kaczmarek Ł., Dobak P.

Geologos

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2015

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Vol. 21, No. 4

249--260

EN

Localised landslide activity has been observed in the area of the plateau slope analysed, in the vicinity of the planned Warsaw Southern Ring Road. Using calculation models quantitative and qualitative evaluations of the impact of natural and anthropogenic load factors on slope stability (and hence, safety) are made. The present paper defines six stages of slope stability analysis, leading to an indication of optimum slope design in relation to the development planned. The proposed procedure produces a ranking of factors that affect slope stability. In the engineering geological conditions under consideration, the greatest factors impacting degradation and failure of slope stability are changes in soil strength due to local, periodic yielding and the presence of dynamic loads generated by intensification of road traffic. Calculation models were used to assess the impact of destabilisation factors and to obtain mutual equivalence with 3D-visualisation relations. Based on this methodology, various scenarios dedicated to specific engineering geological conditions can be developed and rapid stability evaluations of changing slope loads can be performed.

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Sedimentological interpretation and stratigraphical position of glacigenic deposits in the Napęków area (Holy Cross Mountains, Poland)

Ludwikowska-Kędzia M., Pawelec H., Adamiec G.

Geologos

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2015

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Vol. 21, No. 4

261--284

EN

The identification of depositional conditions and stratigraphical position of glacigenic deposits in the Napęków area is important for the genetic and stratigraphical interpretation of Quaternary deposits in the central part of the Holy Cross Mountains, as well as for a revision of the course and extent of Middle Polish (Saalian) glaciations. These deposits comprise a series of diamictons which occur between sandy-gravelly deposits. Based on results of macro- and microscopic sedimentological investigations, analysis of heavy mineral composition, roundness and frosting of quartz grains, as well as OSL dating, this complex must have formed during the Odranian Glaciation (Drenthe, Saalian, MIS 6). Sandy-gravelly deposits are of fluvioglacial and melt-out origin. Diamictons represent subglacial traction till. Their facies diversity is a result of variations in time and space, complex processes of deposition and deformation, responsible for their formation at the base of the active ice sheet. This glacigenic depositional complex was transformed by erosion-denudation and aeolian processes in a periglacial environment during the Vistulian (Weichselian, MIS 5d-2).

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Macroscopic lithotype characterisation of the 1st Middle-Polish (1st Lusatian) Lignite Seam in the Miocene of central Poland

Widera Marek

Geologos

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2012

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Vol. 18, No. 1

1--11

EN

The 1st Middle-Polish (1st Lusatian) Lignite Seam is exploited in open-cast mines in central Poland. A large number of lignite lithotypes, grouped in four lithotype associations, are distinguished: xylitic, detritic, xylo-detritic and detro-xylitic lithotype associations, which show various structures. Each lithotype association was produced under specific peat-forming environmental conditions. In the case of the lignite seams under study they represent all the main environments that are known from Neogene mires, i.e.: fen or open water, bush moor, wet forest swamp and dry forest swamp. For a simple and practical description in the field of both the lignite sections and borehole cores, a new codification for lignite lithotypes is proposed. It is based on the codification of clastic deposits (lithofacies). The practical value of the new lignite lithotype codification is examined in three vertical sections of the 1st Middle-Polish Lignite Seam.