Book review     

Peter Molnar  John D. Weeks  Claude J. Allegre  Yehuda Bock  Stephen K. Dobos  Leszek Czechowski  Kacper R. Rybicki  Krzysztof Haman 《Pure and Applied Geophysics》1987,125(4):679-698

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On geophysical explanation of some irregular variations of the mean latitudes of latitude stations     

Leszek Czechowski  Barbara Kolaczek 《Pure and Applied Geophysics》1985,123(3):398-406

Mean latitude variations computed by Orlovs or other filters have some irregular variations in addition to secular ones. These are of the order of ±0.05 to ±0.1, they can last several years and sometimes show regional similarities. In looking for an explanation of such latitude variations several physical mechanisms have been investigated. The most probable one is the mechanism of stress propagation in the lithosphere and asthenosphere. The consequent gravitational and deformational effects could explain both the magnitude and the time dependance of the irregular latitude variations.  相似文献   

Book review     

Jeremy Bloxham  David Gubbins  Victor C. Li  Leszek Czechowski  Jan Błęcki  Anil Suri  Pierre De Mey  R. Balcer  Maciej Sadowski  Krzysztof E. Haman 《Pure and Applied Geophysics》1989,130(1):127-148

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Gully erosion as a natural hazard: the educational role of geotourism     

Wojciech Zgłobicki  Renata Kołodyńska-Gawrysiak  Leszek Gawrysiak 《Natural Hazards》2015,79(1):159-181

Gully erosion is one of the greatest natural hazards in the loess areas of E. (Eastern) Poland. At the same time, permanent gullies are a major tourist attraction and can provide a basis for the development of geotourism. The study objective was to assess the possibilities of using the loess gullies for educational purposes. Detailed studies were conducted within the municipality of Kazimierz Dolny, an area with an extremely high concentration of permanent gullies. The questionnaire survey of students and tourists (nearly 300 surveys were completed) showed that the respondents’ knowledge of geomorphology was limited, despite their familiarity with gullies. In most cases, they were unable to accurately identify the determinants of gully erosion, its negative effects and methods for preventing it. An assessment of the tourism and geotourism potential of the municipality made it possible to identify the sites (gullies) that can perform an educational function, with regard to gully erosion. The establishment of the Ma?opolska Vistula Gap Geopark, whose highlights will include numerous loess gullies, can pave the way for the development of geotourism.  相似文献   

Thermo-mechanical facies representative of fast and slow flowing ice sheets: the Weichselian ice sheet,a central west Poland case study     

Izabela Szuman  Marek Ewertowski  Leszek Kasprzak 《Proceedings of the Geologists' Association. Geologists' Association》2013

This study deals with an issue of thermo-mechanical facies, reflecting specific thermal and mechanical properties of the subglacial environment. The main objective of this study was to develop a model of glacitectionic deformation and its sedimentary record beneath fast and slow flowing ice sheets, based on investigations conducted in Wielkopolska (west central Poland). Sedimentary structures, mainly at the contact between subglacial tills and glacifluvial sediments, were recognized to delineate typical facies associations in a Weichselian glacigenic succession. Each association was interpreted as a record of the different depositional environments related to different subglacial conditions. Those investigations suggest the substratum was composed of frozen and dry, and wet and mobile spots, and four thermo-mechanical facies were distinguished: A – is representative of slower ice flow, dry and cold subglacial conditions, where driving stresses and normal effective pressure were high; B – is also related to slow ice flow and occurrence of cold subglacial permafrost, but with little amount of unfrozen water (however, higher than in facies A), with similar physical characteristics of the ice sheet as facies A; thermo-mechanical facies C and D represent wet and warm ice sole, with low normal effective pressure and driving stresses, thus lowering sediments’ shear strength and enabling high ice-flow velocities. We suggest that these facies have specific and non-random location, thereby revealing the relationship between subglacial thermo-mechanical conditions and ice sheet dynamics. Slow moving, cold-based ice occurred along ice sheet margins and inter-stream areas, whereas fast-moving, warm-based, well-lubricated ice, was typical of the axial parts of ice streams.  相似文献   

Uniform parameterized theory of convection in medium sized icy satellites of Saturn     

Leszek Czechowski 《Acta Geophysica》2009,57(2):548-566

We develop a parameterized theory of convection driven by radiogenic and tidal heating. The tidal heating depends on eccentricity e of a satellite’s orbit. Using parameterized theory we determine the intensity of convection as a function of e and satellite’s properties. The theory is used for 6 medium sized satellites of Saturn. We find that endogenic activity on Tethys and Dione is possible if e exceeds some critical values e _cr . For Enceladus, e was probably close to the present value for billions of years. We cannot find constrains for e of Mimas and Iapetus. The theory successfully predicts the possibility of present endogenic activity in Dione and rules out such activity in Tethys. Both these facts were recently confirmed by Cassini mission.  相似文献   

Neogene exhumation in the Outer Western Carpathians     

Massimiliano Zattin  Benedetta Andreucci  Leszek Jankowski  Stefano Mazzoli  Rafal Szaniawski 《地学学报》2011,23(5):283-291

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Dynamic migration of rotating neutron stars due to a phase transition instability     

Harald Dimmelmeier  Michal Bejger  Pawel Haensel  J. Leszek Zdunik 《Monthly notices of the Royal Astronomical Society》2009,396(4):2269-2288

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Organic matter from the Callovian (Middle Jurassic) deposits of Lithuania: Compositions,sources and depositional environments     

Leszek Marynowski  Michał Zatoń 《Applied Geochemistry》2010

This study presents the first organic geochemical and petrographical investigation of the Callovian deposits of the eastern part of the Central European Basin. It is shown that in both the terrigenous Papil? Formation (Lower Callovian) and shallow- to deeper-marine facies of the Papartin? and Skinija formations (Middle and Upper Callovian, respectively), terrestrial organic matter predominates. This is reflected by the carbon preference index values higher than 1.2 for all samples and in some cases higher than 2, as well as the occurrence of characteristic higher plant biomarkers like cadalene, dehydroabietane, simonellite and retene. Moreover, in the case of the Papil? Formation, sugiol – a natural product terpenoid produced by distinct conifer families, has been detected in clay sediments. The occurrence of such a biomolecule in the Middle Jurassic clays is reported for the first time. Its occurrence is probably connected with the presence of small wood debris in the clay sediments. In samples of the Papil? Formation, charcoal fragments co-occurring with unsubstituted polycyclic aromatic hydrocarbons were detected, indicating that wildfires took place during the Early Callovian of Lithuania and/or neighbouring areas. In the Middle and Upper marine Callovian sediments of Lithuania there is no evidence of anoxic conditions occurring in the water column. However, periodic anoxic or strongly dysoxic episodes may have occurred, most probably below the photic zone, during the deepest phase of the Late Callovian transgression, as is evidenced from pyrite framboid diameter distribution and general impoverishment of benthic fauna. Huminite reflectance (R_r) values for the investigated area are in the range of 0.21–0.31%, suggesting the occurrence of immature organic matter. Such values indicate that these investigated deposits were close to the surface during their whole diagenetic history, and the thickness of younger cover did not exceed ca. 500 m. This is also supported by a biomarker analysis in which less thermally stable ββ-hopanes and hopenes significantly dominated.  相似文献   

The need for parallel studies on denudation chronology and present-day processes     

Leszek Starkel 《地球表面变化过程与地形》1982,7(4):301-302

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