Petrology of the Baszkówka L5 chondrite: A record of surface‐forming processes on the parent body     

Tadeusz Andrzej PRZYLIBSKI  Andrzej Sylwester PILSKI  Pawe&#x; Przemys&#x;aw ZAGOZ DZ ON  Ryszard KRYZA 《Meteoritics & planetary science》2003,38(6):927-937

Abstract— We review the petrology of Baszkówka, present new microprobe data on mineral constituents, and propose a model for surface properties of the parent body consistent with these data. The low shock index and high porosity of the Baszkówka L5 chondrite mean that considerable primary textural and petrographic detail is preserved, allowing insight into the structure and evolution of the parent body. This meteorite formed in a sedimentary environment resembling that in which pyroclastic rocks are deposited. The origin of the component chondrules, achondritic fragments (mostly olivine and pyroxene aggregates), chondritic‐achondritic aggregates, and compound chondrules can be explained by invoking collision of 2 melted or partially melted planetesimals, each covered with a thin crust. This could have happened at an early stage in the evolution of the solar system, between 1 and 2 Myr after its origin. The collision resulted in the formation of a cloud containing products of earlier magmatic crystallization (chondrite and achondrite fragments) from which new chondrules were created. Particle collision in this cloud produced fragmented chondrules, chondritic‐achondritic aggregates, and compound chondrules. Within this low‐density medium, these particles were accreted on the surface of the larger of the planetesimals involved in the collision. The density of the medium was low enough to prevent grain‐size sorting of the components but high enough to prevent the total loss of heat and to enable the welding of fragments on the surface of the body. The rock material was homogenized within the cloud and, in particular, within the zone close to the planetesimal surface. The hot material settled on the surface and became welded as molten or plastic metal, and sulfide components cemented the grains together. The process resembled the formation of welded ignimbrites. Once these processes on the planetesimal surface were completed, no subsequent recrystallization occurred. The high porosity of the Baszkówka chondrite indicates that the meteorite comes from a near‐surface part of the parent body. Deeper parts of the planetesimal would have been more massive because of compaction.  相似文献   

Composition of brines in halite‐hosted fluid inclusions in the Upper Ordovician,Canning Basin,Western Australia: new data on seawater chemistry     

Volodymyr M. Kovalevych  Tadeusz Marek Peryt  Wenlong Zang  Serhiy V. Vovnyuk 《地学学报》2006,18(2):95-103

Analyses of primary and early diagenetic fluid inclusions in the halite from the Late Ordovician Mallowa Salt, Canning Basin, Western Australia indicate a Ca‐rich composition and high concentration of parent brines in the basin which were close to sylvite and carnallite precipitation. The salt‐bearing series in the sampled interval was overheated up to 62 °C. The recorded differences in gas compositions result from the input of several gas sources including dispersed organic matter in the salt series and hydrocarbon deposits in the underlying rocks. The high concentration of the brines in fluid inclusions does not allow quantitative reconstruction of the chemical composition of Late Ordovician parent seawater. Using the information from Early Cambrian and Late Silurian basins as a proxy, however, the new data indicate that Late Ordovician seawater was undoubtedly Ca‐rich and, in comparison with modern seawater, had a similar K content, considerably lower Mg content (c. 30%), approximately three times the Ca content and one‐third the SO₄ content.  相似文献   

Combined mine tremors source location and error evaluation in the Lubin Copper Mine (Poland)     

Andrzej Leniak  Grzegorz Pszczo&#x;a 《Tectonophysics》2008,456(1-2):16

A modified method of mine tremors location used in Lubin Copper Mine is presented in the paper. In mines where an intensive exploration is carried out a high accuracy source location technique is usually required. The effect of the flatness of the geophones array, complex geological structure of the rock mass and intense exploitation make the location results ambiguous in such mines. In the present paper an effective method of source location and location's error evaluations are presented, combining data from two different arrays of geophones. The first consists of uniaxial geophones spaced in the whole mine area. The second is installed in one of the mining panels and consists of triaxial geophones. The usage of the data obtained from triaxial geophones allows to increase the hypocenter vertical coordinate precision. The presented two-step location procedure combines standard location methods: P-waves directions and P-waves arrival times. Using computer simulations the efficiency of the created algorithm was tested. The designed algorithm is fully non-linear and was tested on the multilayered rock mass model of the Lubin Copper Mine, showing a computational better efficiency than the traditional P-wave arrival times location algorithm. In this paper we present the complete procedure that effectively solves the non-linear location problems, i.e. the mine tremor location and measurement of the error propagation.  相似文献   

Groundwater recharge of carbonate aquifers of the Silesian-Cracow Triassic (southern Poland) under human impact     

Andrzej Kowalczyk  Andrzej J. Witkowski 《Environmental Geology》2008,55(2):235-246

A Triassic carbonate unit has been intensively drained by zinc and lead ore mines and numerous borehole fields since the nineteenth century. Its groundwater recharge has increased due to: pumping of water from boreholes, mining activity, and urbanization. An approach to determine the amounts of the recharge at a variety of spatial scales is presented in the paper. Different methods were used to identify and quantify recharge components on a regional and local scale: mathematical modelling was performed for four aquifers included in an aquifer system, an analytical estimation based on the assumption that an average recharge is equal to the average discharge of the hydrogeological system—for six man-made drainage centres, and the method of water level fluctuation (WLF) was applied in one observation borehole. Results of modelling have been supplemented by observation of environmental tracers (δ¹⁸O, δ²H, ³H), noble gases temperatures, and ⁴He_exc in groundwater. The regional aquifer’s current recharge according to estimations performed by means of modelling varies from 39 to 101 mm/year on average. Depending on the aquifer site the average precipitation ranges from 779 to 864 mm/year. In the confined part of the aquifer average recharge ranges from 26 to 61 mm/year. Within outcrops average recharge varies from 96 to 370 mm/year. Current recharge estimated by the analytical method for man-made drainage centres varies from 158 up to 440 mm/year. High values are caused by different recharge sources like precipitation, induced leakage from shallow aquifers, and water losses from streams, water mains and sewer systems. Pumping of water, mining and municipal activities constitute additional factors accounting for the intensified recharge.  相似文献   

The soilmodels.info project   总被引：1，自引：0，他引：1  

Gerd Gudehus  Angelo Amorosi  Antonio Gens  Ivo Herle  Dimitrios Kolymbas  David Mašín  David Muir Wood  Andrzej Niemunis  Roberto Nova  Manuel Pastor  Claudio Tamagnini  Gioacchino Viggiani 《国际地质力学数值与分析法杂志》2008,32(12):1571-1572

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Acoustic semi-tomography in studies of the structure and function of the marine ecosystem     

Orlowski  Andrzej 《ICES Journal of Marine Science》2003,60(6):1392-1397

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System for normalization of a hamiltonian function based on lie series     

Krzysztof Gozdziewski  Andrzej J. Maciejewski 《Celestial Mechanics and Dynamical Astronomy》1990,49(1):1-10

A software system for normalization of a Hamiltonian function is described. A few examples of its applications are given. It is written in PASCAL and runs on an IBM XT/AT with 640 KB memory.  相似文献   

Verification of the dualism ordering method by the canonical correspondence analysis: fish community samples     

Tadeusz Penczak  Francisco Godinho  Angelo A. Agostinho 《Limnologica》2002,32(1)

Two ordination techniques (Romaniszyn diagram, RD, and Canonical correspondence analysis, CCA) were applied to the same data set (fish assemblage composition along two Paraná river tributaries and associated environmental variables), to identify spatial community patterns and further to evaluate the performance of RD. The major patterns in these Brazilian streams were successfully revealed by both methods (i.e. clear separation of both tributaries on the basis of fish assemblage composition and environmental factors), but more complex situations may limit the application of RD in comparison with CCA.  相似文献   

Numerical modelling method for wave propagation in a linear viscoelastic medium with singular memory   总被引：1，自引：0，他引：1  

Jian-Fei Lu  Andrzej Hanyga 《Geophysical Journal International》2004,159(2):688-702

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Application of Web-GIS and Geovisual Analytics to Monitoring of Seabed Evolution in South Baltic Sea Coastal Areas     

Marcin Kulawiak  Andrzej Chybicki 《Marine Geodesy》2018,41(4):405-426

Regular surveys of coastal zone seabed deliver important information about geomorphologic processes such as silting of waterways. The recent introduction of the Sentinel series of sensors has allowed for the use of satellite sensing for shallow bathymetry morphology monitoring. In this context, this article presents a dedicated Geographic Information System for Baltic Sea shallow water depth monitoring on the basis of Sentinel-2 imagery. The system employs Geovisual Analytics for differential analysis of bathymetry changes as well as monitoring the visibility of known wrecks in the coastal waters of Southern Baltic Sea. Results are verified with regard to known changes in shallow water bathymetry between 28 June 2015 and 3 March 2017.  相似文献