Deciphering late Devonian–early Carboniferous P–T–t path of mylonitized garnet-mica schists from Prins Karls Forland,Svalbard     

Karolina Kośmińska  Frank S. Spear  Jarosław Majka  Karol Faehnrich  Maciej Manecki  Karsten Piepjohn  Winfried K. Dallmann 《Journal of Metamorphic Geology》2020,38(5):471-493

Quartz-in-garnet inclusion barometry integrated with trace element thermometry and calculated phase relations is applied to mylonitized schists of the Pinkie unit cropping out on the island of Prins Karls Forland, western part of the Svalbard Archipelago. This approach combines conventional and novel techniques and allows deciphering of the pressure–temperature (P–T) evolution of mylonitic rocks, for which the P–T conditions could not have been easily deciphered using traditional methods. The results obtained suggest that rocks of the Pinkie unit were metamorphosed under amphibolite facies conditions at 8–10 kbar and 560–630°C and mylonitized at ~500 to 550°C and 9–11 kbar. The P–T results are coupled with in-situ Th–U-total Pb monazite dating, which records amphibolite facies metamorphism at c. 359–355 Ma. This is the very first evidence of late Devonian–early Carboniferous metamorphism in Svalbard and it implies that the Ellesmerian Orogeny on Svalbard was associated with metamorphism up to amphibolite facies conditions. Thus, it can be concluded that the Ellesmerian collision between the Franklinian margin of Laurentia and Pearya and Svalbard caused not only commonly accepted brittle deformation and weak greenschist facies metamorphism, but also a burial and deformation of rock complexes at much greater depths at elevated temperatures.  相似文献   

Correction to: Application of Multichannel Analysis of Surface Waves to S-Phase Wave Anisotropy Estimation     

Iwona Stan-Kłeczek  Maciej J. Mendecki 《Acta Geophysica》2018,66(6):1525-1525

  相似文献   

Conditioning clayey soils with a dispersant agent for Deep Soil Mixing application: laboratory experiments and artificial neural network interpretation     

Salvatore  Erminio  Modoni  Giuseppe  Spagnoli  Giovanni  Arciero  Michela  Mascolo  Maria Cristina  Ochmański  Maciej 《Acta Geotechnica》2022,17(11):5073-5087

Acta Geotechnica - Plasticity of clays makes Deep Soil Mixing (DSM) problematic due to the tendency of the material to congest the rotating blades, reduce mixing efficiency and remain...  相似文献   

Sustainable floodplain management for flood prevention and water quality improvement     

Edyta Kiedrzyńska  Marcin Kiedrzyński  Maciej Zalewski 《Natural Hazards》2015,76(2):955-977

  相似文献   

Composition and origin of organic matter in surface sediments of Lake Sarbsko: A highly eutrophic and shallow coastal lake (northern Poland)   总被引：1，自引：0，他引：1  

Micha? Woszczyk  Achim Bechtel  Reinhard Gratzer  Maciej J. Kotarba  Miko?aj Kokociński  Jens Fiebig  Roman Cie?liński 《Organic Geochemistry》2011,42(9):1025-1038

We present an organic geochemical study of surface sediments of Lake Sarbsko, a shallow coastal lake on the middle Polish Baltic coast. The aim was to provide evidence concerning the origin of the organic matter (OM) and its compositional diversity in surface deposits of this very productive, highly dynamic water body. The content and composition of the OM in the bottom sediments were investigated at 11 sampling stations throughout the lake basin. OM sources were assigned on the basis of bulk indicators [total organic carbon (TOC), total nitrogen (TN), δ¹³C_TOC and δ¹⁵N and extractable OM yield], biomarker composition of extractable OM and compound-specific C isotope signatures. The source characterization of autochthonous compounds was verified via phytoplankton analysis. The distribution of gaseous hydrocarbons in the sediments, as well as temporal changes in lake water pH, the concentration of DIC (dissolved inorganic carbon) and δ¹³C_DIC were used to trace OM decomposition.The sedimentary OM is composed mainly of well preserved phytoplankton compounds and shows minor spatial variability in composition. However, the presence of CH₄ and CO₂ in the bottom deposits provides evidence for microbial degradation of sedimentary OM. The transformation of organic compounds in surface, bottom and pore waters via oxidative processes influences carbonate equilibrium in the lake and seasonally favours precipitation or dissolution of CaCO₃.The data enhance our understanding of the relationships between the composition of sedimentary OM and environmental conditions within coastal ecosystems and shed light on the reliability of OM proxies for environmental reconstruction of coastal lakes.  相似文献   

Constraining clastic input controls on magnetic susceptibility and trace element anomalies during the Late Devonian punctata Event in the Western Canada Sedimentary Basin     

Maciej G. Śliwiński  Michael T. Whalen  Franz J. Meyer  František Majs 《地学学报》2012,24(4):301-309

  相似文献   

Are modern metaheuristics successful in calibrating simple conceptual rainfall–runoff models?     

Adam P. Piotrowski  Maciej J. Napiorkowski  Jaroslaw J. Napiorkowski  Marzena Osuch  Zbigniew W. Kundzewicz 《水文科学杂志》2017,62(4):606-625

In recent years sampling approaches have been used more widely than optimization algorithms to find parameters of conceptual rainfall–runoff models, but the difficulty of calibration of such models remains in dispute. The problem of finding a set of optimal parameters for conceptual rainfall–runoff models is interpreted differently in various studies, ranging from simple to relatively complex and difficult. In many papers, it is claimed that novel calibration approaches, so-called metaheuristics, outperform the older ones when applied to this task, but contradictory opinions are also plentiful. The present study aims at calibration of two simple lumped conceptual hydrological models, HBV and GR4J, by means of a large number of metaheuristic algorithms. The tests are performed on four catchments located in regions with relatively similar climatic conditions, but on different continents. The comparison shows that, although parameters found may somehow differ, the performance criteria achieved with simple lumped models calibrated by various metaheuristics are very similar and differences are insignificant from the hydrological point of view. However, occasionally some algorithms find slightly better solutions than those found by the vast majority of methods. This means that the problem of calibration of simple lumped HBV or GR4J models may be deceptive from the optimization perspective, as the vast majority of algorithms that follow a common evolutionary principle of survival of the fittest lead to sub-optimal solutions.  相似文献   

Labile and stabile soil organic carbon fractions in surface horizons of mountain soils–relationships with vegetation and altitude     

Oskar Bojko  Cezary Kabala  Łukasz Mendyk  Maciej Markiewicz  Magdalena Pagacz-Kostrzewa  Bartłomiej Glina 《山地科学学报》2017,14(12):2391-2405

Global and local climate changes could disturb carbon sequestration and carbon stocks in forest soils. Thus, it is important to characterize the stability of soil organic matter and the dynamics of soil organic carbon (SOC) fractions in forest ecosystems. This study had two aims: (1) to evaluate the effects of altitude and vegetation on the content of labile and stabile forms of organic carbon in the mountain soils; and (2) to assess the impact of the properties of soil organic matter on the SOC pools under changing environmental conditions. The studies were conducted in the Karkonosze Mountains (SW Poland, Central Europe). The content of the most labile fraction of carbon (dissolved organic carbon, DOC) decreases with altitude, but the content of fulvic acids (FA), clearly increases in the zone above 1000 m asl, while the stabile fraction (humins, non-hydrolyzing carbon) significantly decreases. A higher contribution of stabile forms was found in soils under coniferous forests (Norway spruce), while a smaller - under deciduous forests (European beech) and on grasslands. The expected climate change and the ongoing land use transformations in the zone above 1000 m asl may lead to a substantial increase in the stable humus fraction (mainly of a non-hydrolyzing carbon) and an increase in the SOC pools, even if humus acids are characterized by a lower maturity and greater mobility favorable to soil podzolization. In the lower zone (below 1000 m asl), a decrease in the most stable humus forms can be expected, accompanied by an increase of DOC contribution, which will result in a reduction in SOC pools. Overall, the expected prevailing (spatial) effect is a decreasing contribution of the most stable humus fractions, which will be associated with a reduction in the SOC pools in medium-high mountains of temperate zone of Central Europe.  相似文献   

Differences in the abiotic parameters of water in coastal lakes in the light of the EU water framework directive: An example of the Polish southern Baltic coast     

Roman Cieśliński  Maciej Major 《Acta Geophysica》2012,60(4):1159-1179

Coastal lakes have a specific hydrological regime determined by the influence of sea and inland water and the local hydrographic conditions. There are several problems concerning the protection and assessment of water quality of these bodies. The most important features differentiating coastal lakes from other lakes are: high salinity, a wide range of seasonal and short-term water quality changes, and specific aquatic ecosystems adapted to these conditions. These matters have not been sufficiently taken into account in the existing classifications and typologies of lakes in Poland. The problem has not been solved by the establishment of the adequate reference conditions and new guidelines for the classification of water status (which are being prepared according to the Common Strategy for the Implementation of the Water Framework Directive) regarding inland surface waters (rivers and lakes) and marine waters (coastal and transitional). An important issue is to define criteria which would help to distinguish all those hydrographic objects and to establish water quality standards for them.  相似文献   

Methods of searching for planets around pulsars     

Maciej Konacki  Andrzej J. Maciejewski 《Monthly notices of the Royal Astronomical Society》1999,308(1):167-179

We analyse different methods of searching for planets around neutron stars by timing observations of pulsars. To this end, we study a few interesting models describing TOA residual variations that are observed, or could be observed, and which can mimic planets. We carry out a detailed theoretical analysis of the behaviour of these methods in the situations mentioned. We show that it is very helpful to look at these phenomena as some kind of quasi-periodic variations of residuals of time of arrival of pulsar pulses. We demonstrate that such a model-independent approach leads to promising conclusions that can be useful when analysing timing observations of pulsars to find planets or to prove that observed phenomena are of planetary origin.  相似文献