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Abstract

The Bulletin of the Polish Academy of Sciences: Technical Sciences (Bull.Pol. Ac.: Tech.) is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred: Artificial and Computational Intelligence, Biomedical Engineering and Biotechnology, Civil Engineering, Control, Informatics and Robotics, Electronics, Telecommunication and Optoelectronics, Mechanical and Aeronautical Engineering, Thermodynamics, Material Science and Nanotechnology, Power Systems and Power Electronics. Journal Metrics: JCR Impact Factor 2018: 1.361, 5 Year Impact Factor: 1.323, SCImago Journal Rank (SJR) 2017: 0.319, Source Normalized Impact per Paper (SNIP) 2017: 1.005, CiteScore 2017: 1.27, The Polish Ministry of Science and Higher Education 2017: 25 points. Abbreviations/Acronym: Journal citation: Bull. Pol. Ac.: Tech., ISO: Bull. Pol. Acad. Sci.-Tech. Sci., JCR Abbrev: B POL ACAD SCI-TECH Acronym in the Editorial System: BPASTS.
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Abstract

Textural properties and microstructures are commonly used properties in the analysis of Pleistocene and older glacial deposits. However, contemporary glacial deposits are seldom studied, particularly in the context of post-depositional changes. This paper presents the results of a micromorphological study of recently deposited tills in the marginal zones of Hansbreen and Torellbreen, glaciers in southwestern Spitsbergen. The main objectives of this study were to compare modern tills deposited in subglacial and supraglacial conditions, as well as tills that were freshly released from ice with those laid down several decades ago. The investigated tills are primarily composed of large clasts of metamorphic rocks and represent coarse-grained, matrix-supported diamictons. The tills reveal several characteristic features for ductile (e.g. turbate structures) and brittle (e.g. lineations, microshears) deformations, which have been considered to be indicative of subglacial conditions. In supraglacial tills, the same structures are common as in the subglacial deposits, which points to the preservation of the primary features, though the sediment was transferred up to the glacier surface due to basal ice layer deformation and redeposited as slumps, or to formation of similar structures due to short-distance sediment re-deposition by mass flows. This study revealed that it might not be possible to distinguish subglacial and supraglacial tills on the basis of micromorphology if the latter are derived from a subglacial position. The only noted difference was the presence of iron oxide cementation zones and carbonate dissolution features in supraglacial tills. These features were found in tills that were deposited at least a few years ago and are interpreted to be induced by early post-depositional processes involving porewater/sediment interactions.
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Abstract

Modern hydrology of a typical Arctic fjord (Hornsund, SW Spitsbergen, Sval− bard) was investigated and compared with commonly used in paleoceanography proxies: benthic foraminiferal assemblages and their stable isotope (#2;18O and #2;13C) composition. The benthic foraminifera from Hornsund comprised 45 species and 28 genera. Their spatial variations follow the zonation pattern, resulting from the influence of Atlantic water at the fjord mouth and glacial meltwaters at the fjord head. At the mouth of the fjord, the total number of species and the contribution of agglutinating species were the highest. In the in− ner part of fjord, the foraminiferal faunas were poor in species and individuals, and aggluti− nating species were absent. “Living” (stained) foraminifera were found to be common throughout the short sediment cores (~10 cm long) studied. The stable isotope values of #2;18O and #2;13C were measured on tests of four species: Elphidium excavatum forma clavata, Cassidulina reniforme, Nonionellina labradorica and Cibicides lobatulus. The results con− firmed the importance of species−specific vital effects, particularly in the case of C. loba− tulus. The variability in the isotopic composition measured on different individuals within a single sample are comparable to isotopic composition of the same species test between sam− pling stations. The temperatures and bottom water salinities calculated from #2;18O values in different foraminifera tests mirrored those recorded for bottom waters in the central and outer fjords relatively well. However, in the case of the inner fjord, where winter−cooled bottom waters were present, the calculated values from #2;18O were systematically higher by about 2#3;C. The obtained results imply that particular caution must be taken in interpretation of fjord benthic foraminifera assemblages in high resolution studies and in selection of ma− terial for isotope analyses and their interpretation in cores from inner fjords or silled fjords, where winter−cooled waters may be present.
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Abstract

We test the application of dendrochronological methods for dating and assessing the environmental impacts of tsunamis in polar regions, using an example of the 21 November 2000 landslide−generated tsunami in Vaigat Strait (Sullorsuaq Strait), West Greenland. The studied tsunami inundated a c . 130 m−wide coastal plain with seawater, caused erosion of beaches and top soil and covered the area with an up to 35 cm−thick layer of tsunami deposits composed of sand and gravel. Samples of living shrub, Salix glauca (greyleaf willow) were collected in 2012 from tsunami−flooded and non−flooded sites. The tree−ring analyses reveal unambiguously that the tsunami−impacted area was immediately colonized during the following summer by rapidly growing shrubs, whilst one of our control site specimens records evidence for damage that dates to the time of the tsunami. This demonstrates the potential for dendrochronological methods to act as a precise tool for the dating of Arctic paleotsunamis, as well as rapid post−tsunami ecosystem recovery. The reference site shrubs were likely damaged by solifluction in the autumn 2000 AD that was triggered by high seasonal rainfall, which was itself a probable contributory factor to the tsunami−generating landslide.
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Abstract

We have evidence of a meteorite impact near the village of Morasko in Poland around 5,500 years ago. What can it tell us about the past and the future?
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