BazTech - Yadda

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Kartografia 4D w strefie brzegowej południowego Bałtyku : zadanie państwowej służby geologicznej

Uścinowicz Grzegorz

Przegląd Geologiczny

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2023

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Vol. 71, nr 3

138--144

EN

The research task Geological integrated coastal zone mapping concerns the recognition and visualization of the geological structure of the Polish coastal zone, enriched with the modelling of erosion-accumulation processes, including prediction of changes in the position of the shoreline and identification of geohazards. It has been running since 2012 and implements multi-instrumental research methods. To date, a total length of about 155 km of the Polish coastal zone has been studied in an area of about 621 km 2 . The main results of the work are presented in the form of maps (e.g., lithogenetic, hydrogeological, geohazard), models (e.g., morpho-geological, hydrodynamic, predictive) and specialized analyses (e.g., morphodynamical, slope stability). In general, the work carried out is done for a utilitarian purpose, i.e. aimed at the practical use of environmental information. According to the standards of the Polish Geological Survey, most of the geological data acquired can be geoprocessed.

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Multivariate statistical analysis and geospatial approach for evaluating hydro geochemical characteristics of meltwater from Shaune Garang glacier, Himachal Pradesh, India

Kumar Ramesh, Kumar Rajesh, Bhardwaj Anshuman, Singh Atar, Singh Shaktiman, Kumari Anupma, Sinha Ravindra Kumar

Acta Geophysica

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2023

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Vol. 71, no. 1

323--339

EN

The study focuses on the hydro-geochemistry of Shaune Garang glacier’s meltwater concerning glacial geomorphology. Seventy-nine water samples (53 in 2016 and 26 in 2017) of ablation season were analysed. The cations were dominant in the order Ca2+ > Mg2+ > Na+ > K+, and the anions in the order HCO3- > SO4 2- > Cl- > NO3-. The result demonstrated that HCO3 - were the abundant ions, accounting for 41.03 and 34.84% of the total ionic budget (TZ). The high ionic proportions of (Ca2+ + Mg2+) versus TZ+ and (Ca2+ + Mg2+) versus (Na+ + K+) were identified as the primary factors influencing dissolved ion chemistry in meltwater. Piper diagram shows that Ca2+–HCO3- type water is the most common, followed by Mg2+–HCO3-. In addition, a remote sensing approach has been used to find the possible source of the chemical constituents in the meltwater. The catchment geology has been mapped on various scales, including diverse rocks and unconsolidated surface materials containing “quartz and carbonate minerals”. Layered silicates (LS) and “hydroxyl-bearing minerals” are not as common as they used to be, but their availability varies greatly in the area where they are found. The distribution of LS minerals within the catchment are majorly found at lower altitudes, which implies the weathering mechanism due to the interaction of meltwater and parental rock. Multivariate analysis revealed that CO3 and SiO3 weathering, sulphate dissolution, and pyrite oxidation dominate dissolved ion concentrations. Chemometric analysis of meltwater hydro-geochemistry through principal component analysis explains 72.1% of the total variance of four PCs. PCs 1, 2, 3, and 4 explain 39.21%, 12.91%, 10.24%, and 9.74% of variance, respectively, in 2016. Similarly, in 2017, four PCs explain 69.91% of the total variance. PC 1, 2, 3, and 4 can explain 26.62%, 20.12%, 12.64%, and 10.52% of variance.

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Geological mapping using extreme gradient boosting and the deep neural networks: application to silet area, central Hoggar, Algeria

Elbegue Abderrahmane Aref, Allek Karim, Zeghouane Hocine

Acta Geophysica

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2022

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Vol. 70, no 4

1581--1599

EN

Nowadays, machine learning algorithms are considered a powerful tool for analyzing big and complex data due to their ability to deliver accurate and fast results. The main objective of the present study is to prove the effectiveness of the extreme gradient boosting (XGBoost) method as well as employed data types in the Saharan region mapping. To reveal the potential of the XGBoost, we conducted two experiments. The first was to use different combinations of: airborne gamma-ray spectrometry data, airborne magnetic data, Landsat 8 data and digital elevation model. The objective is to train 9 XGBoost models in order to determine each data type sensitivity in capturing the lithological rock classes. The second experiment was to compare the XGBoost to deep neural networks (DNN) to display its potential against other machine learning algorithms. Compared to the existing geological map, the application of XGBoost reveals a great potential for geological mapping as it was able to achieve a correlation score of (78%) where igneous and metamorphic rocks are easily identified compared to sedimentary rocks. In addition, using different data combinations reveals airborne magnetic data utility to discriminate some lithological units. It also reveals the potential of the apparent density, derived from airborne magnetic data, to improve the algorithm’s accuracy up to 20%. Furthermore, the second experiment in this study indicates that the XGBoost is a better choice for the geological mapping task compared to the DNN. The obtained predicted map shows that the XGBoost method provides an efficient tool to update existing geological maps and to edit new geological maps in the region with well outcropped rocks.

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Prace geologów Państwowego Instytutu Geologicznego za granicą

Salski Wojciech

Przegląd Geologiczny

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2020

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Vol. 68, nr 5

437--448

EN

Geologists of the Polish Geological Institute carried out their professional activities abroad as part of geological expeditions, in teams of several people and on individual contracts, including as experts of the United Nations. In terms of the scope of work, most of their activities were focued on research on mineral resources, mapping, geochemistry, hydrogeology and geophysics, as well as on teaching of geology at the university level. The beginnings date back to the turn of the 1950s. It began with a geological expedition to Vietnam. Mongolia was the goal of subsequent expeditions on a much wider scale. The researches were conducted from the beginning of the 1960s until the end of the 1980s. The contracts, performed in groups of several people and individually, covered about 20 countries; most of them on the African continent. They focused primarily on the search for metal ore deposits, hard coal, and chemical and rock raw materials. PGI geologists also worked as UN experts in Benin, Burundi, Chad, Gabon, Haiti, India, Madagascar, Mauritania and Niger. The results of their work on various continents were the discoveries of numerous mineral deposits and the recognition of geological structure over an area of thousands of square kilometres.

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Processing and Analysis of ASTER and Landsat 8 Scenes to Aid in Geological Mapping: A Case Study of Murchison Greenstone Belt Area, South Africa

Thomas Abraham

Geomatics and Environmental Engineering

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2020

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Vol. 14, no. 3

107--123

EN

This paper presents processing and analysis results of ASTER and Landsat 8 scenes to aid in geological mapping of Murchison Greenstone Belt region of Limpopo Province, South Africa. Images of ASTER acquired in 2005 and 2006 and Landsat 8 acquired in 2019 were downloaded and subset covering 5 mapping sheets was extracted. Images of different band ratios and band combinations were experimented using ENVI and SNAP software to identify suitable band/band ratio combinations to produce FCCs that enabled discrimination of lithology, structural features, lineaments, alteration and iron oxides, land/ water, surface features, vegetation cover and healthy vegetation etc. Using DEM data, slope and shaded relief were also prepared that enabled the identification of the extent of protruded outcrops, some structural features and lineaments using different FCC displays. These datasets prepared in ENVI file format were later exported to GeoTiff/Imagine file for display in ArcMap by the mapping geologists. FCCs made in various band combinations, ratio combination and also with slope are useful in discriminating geology, structural features and protruded outcrops including dykes that are not so visible in a true colour image of the same resolution. This study could illustrate the usefulness of remote sensing analysis to aid in geological mapping using freely available ASTER and Landsat 8 data.

PL

W artykule przedstawiono wyniki przetwarzania i analizy obrazów zarejestrowanych przez satelity ASTER oraz Landsat 8. Czynności te wykonane zostały w celu sporządzenia mapy geologicznej dla regionu Murchison Greenstone Belt w prowincji Limpopo, w Afryce Południowej. Zdjęcia wykonane przez ASTER pochodzą z lat 2005 i 2006, natomiast te zarejestrowane przez Landsat 8 z 2019 roku. Analizowane zdjęcia zostały tak dobrane, aby obejmowały obszar odpowiadający pięciu arkuszom mapy geologicznej. Eksperymentowano z wykorzystaniem oprogramowania ENVI i SNAP w celu stworzenia obrazów, które byłyby pomocne w zidentyfikowaniu makroskopowych cech skał, ich struktury, linii nieciągłości, przeobrażeń minerałów i tlenku żelaza, linii pomiędzy lądem i wodą, cech powierzchni, pokrycia roślinnością, wegetacji roślin etc. Korzystając z danych DEM, przygotowano obrazy przedstawiające rzeźbę terenu, które pozwoliły na określenie wysokości terenu, niektórych cech strukturalnych i linii szkieletowych. Wszystkie obrazy zostały później wyeksportowane do plików w formatach GeoTiff i Imagine w celu wyświetlenia ich w ArcMap. Obrazy te okazały się przydatne w rozróżnianiu cech geologicznych i konstrukcyjnych oraz wysokości obiektów, w tym wałów, które nie są dobrze widoczne na obrazach w naturalnych kolorach. Badanie to potwierdza przydatność analizy teledetekcyjnej w tworzeniu map geologicznych z wykorzystaniem swobodnie dostępnych danych z satelitów ASTER i Landsat 8.

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Ruchy masowe a interpretacja budowy geologicznej : przykład osuwiska na górze Drogosz w paśmie Zaworów (Sudety Środkowe)

Kowalski A.

Przegląd Geologiczny

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2017

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Vol. 65, nr 2

96--104

EN

Recognition and precise delimitation of landslide-affected areas, especially in the mountains, have been a challenge so far. New opportunities emerged after dissemination of high- resolution Digital Elevation Models generated by Airborne Laser Scanning (ALS), which are also used to processing and visualization of geological data. This paper touches the issue in both aspects mentioned above, and presents results of morphometric analysis of a landslide on the northern slope of the Drogosz hill within the Zawory Range, in the southern part of the Krzeszów Basin (Central Sudetes). Attempts ofreconstruction ofthe slip surface and estimation oftotal volume of the landslide colluvialfill were undertaken. Furthermore, differential maps were compiled. They were a basis for the spatial distribution of thickness evaluation. The Drogosz hill landslide seems to be strictly related to the geological structure of the research area. The Zawory Range is composed of Upper Cretaceous, Lower Triassic (Buntsandstein) and Permian (Rotliegendes) rocks. Lack of recognition of landslide phenomena was probably the main reason of misleading interpretations of the Krzeszów area geology. The paper also provides comments on the existing concepts of the geological structure of the Krzeszów Basin, especially of the Łączna Anticline.

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Zasięg obszarów objętych osuwiskami w Górach Kamiennych (Sudety Środkowe) : porównanie map geologicznych i cyfrowego modelu wysokości z danych LiDAR

Migoń P., Jancewicz K., Kasprzak M.

Przegląd Geologiczny

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2014

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Vol. 62, nr 9

463--471

EN

The east-central part of the Kamienne Mountains in the Sudetes has long been known as an area where landslides occur in abundance. Their extent was shown on first detailed geological maps from the early 20th century and later on Polish geological maps published in the 1970 and 1990. The total landslide area mapped was about 100 ha. The availability of LiDAR data allowed to build digital elevation models of very high resolution and to attempt landslide mapping using diagnostic landform assemblages as guidelines. 30 separate landslides have been mapped, including complex landslide areas involving overlapping landslide bodies oflikely different origin. The total landslide area is at least300 ha, while the largest complexes cover 40-50 ha. LiDAR-based models proved extremely useful in landslide mapping, espe- cially in forested areas.