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Palaeoenvironmental and palaeoclimatic inferences based on X-ray computer tomography: a case study of alkaline lake deposits in Hungary

Alzoubi Nour N., Gulyas Sandor, Geiger Janos

Geologos

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2023

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Vol. 29, No. 1

33--49

EN

Widely distributed freshwater carbonate sediments, i.e., limestone, dolomitic limestone and dolomite, developed in inter-dune alkaline ponds of the Danube-Tisza Interfluve in the centre of the Carpathian Basin during the Holocene. The key parameters that determine the formation of any given type of carbonate mineral (calcite, dolomite) are temperature, evaporation rate, pH and ion concentrations, in addition to CO2 absorption by aquatic plants. CT analysis is capable of recording small-scale density variations attributable to compositional differences of sedimentary rocks. As the type and proportion of rock-forming minerals and other components is an artifact of past environmental and climatic conditions, CT values may act as potential palaeoenvironmental proxies. The present study compares variations in rock-forming components obtained for freshwater carbonates utilizing the CT method with already available geochemical and palaeoecological proxy data. Variations in molluscan ecology and isotope geochemistry, sedimentation times and CT-based rock density values all indicate the relevance of millennial-scale, climate-driven changes in carbonate formation. As previously observed, the emergence of colder conditions in the North Atlantic, which resulted in increased cyclonic activity and heavier rainfall in western Europe and the Danube watershed area between 10.3 and 9.3 kyr cal BP, resulted in the emergence of humid conditions favouring a rise in the groundwater table at our site and precipitation of calcite from pore waters as opposed to high-magnesium calcite. This is clearly reflected in a negative shift in CT density values in our dated rock samples.

2

Statystyczna analiza strugi urobku generowanej przez koparkę kołową

Czaplicki J.

Górnictwo Odkrywkowe

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2014

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R. 55, nr 1

22--28

PL

Przedmiotem rozważań w niniejszej pracy jest strumień urobku generowany przez koparkę kołową, mając na uwadze jego właściwości statystyczne. Informacja o zidentyfikowanych własnościach stanowiła podstawę do wyboru modelu opisującego ten strumień. Analiza została dokonana w oparciu o dane kopalniane, jakie zebrano przy realizacji pracy doktorskiej wykonywanej na Politechnice Wrocławskiej. W literaturze opisującej wnioskowanie o właściwościach strumienia na podstawie zebranego materiału, zaprezentowano nieco inne rezultaty aniżeli w niniejszej pracy.

EN

A subject of consideration here is a stream of excavated rock won by BWE taking into account statistical properties of the stream. Information on the identified properties was a ground to select an appropriate model that describes the stream. Statistical analysis was done basing on data collected from the field investigation that was carried out to accomplish Ph.D. dissertation realised on Wrocław Technical University. In literature describing statistical inference on the properties of the stream a different approach and results are presented than that described here.

3

Thermal conductivity of 2D random interfaces

Szecówka M., Domański Z.

Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej

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2010

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Vol. 9, nr 2

229-234

EN

Heat transfer through dense granular interfaces formed by squares or triangles with randomly assigned thermal conductivities is discussed. The effective thermal conductivities of the interface are found by means of the steady heat flux induced by connection of interface with the external heat source assuring the constant value of boundary temperature. Some statistical properties of effective conductivities are also presented.