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Identyfikacja kraterów uderzeniowych ze względu na rodzaj środowiska

100%
Brachaniec T., Brom K.
Acta Societatis Metheoriticae Polonorum
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2015
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vol. 6
26-33
EN
It seems that the only correct way to identify impact craters is a combination of theoretical analysis, visual observation and experimental analysis, which are inextricably linked to the environment in which the crater was formed. Undoubtedly, the shock metamorphism is an essential diagnostic tool for the identification of the crater. The depth of water is a major problem in the formation of the marine craters.
2
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Wykorzystanie danych Numerycznego Modelu Terenu do poszukiwania i wstępnej identyfikacji struktur impaktowych

88%
Walesiak T.
Acta Societatis Metheoriticae Polonorum
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2020
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vol. 11
110-124
EN
Is it possible that in Poland, instead of Morasko and still unconfirmed structures Porzadzie, Jaszczulty and Ochudno, may exist some other impact craters? To answer this question, investigations were performed, which were based on the digital elevation models. There are plenty of cavities, having different origin (e.g. a result of past glaciations, human activities or the Second World War), where some criteria may be applied, which could help to distinguish one from another. The main assumption was that during oblique impact (low angle in relation to the surface) there may develop special type of craters having cardioid (heart-shaped) ejecta pattern (as well as shape of cavity), with axis of symmetry parallel to the initial trajectory. Such structures were observed many times during experiments as well as can be easily found on other celestial bodies. Having preserved rims, even if they are much shallower than typical craters (because of secondary changes), such cavities are perfect candidates to be suspected of the impact origin. As a result of research between 2015 and 2017 there were discovered 3 locations (instead of Ochudno) with heart-shaped structures, which may represent combined effect of ejection angles, velocities and directions, known from experiments and confirmed craters. In all cases there are noticeable rims. The largest “spoon-like” structure, discovered near the Rowista village, is almost perfect copy of a very unusual elongated crater located north of the Acheron Fossae on Mars.
3
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Analiza cech impaktu ukośnego na przykładzie struktur Porządzie, Jaszczułty i Ochudno

75%
Walesiak T.
Acta Societatis Metheoriticae Polonorum
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2016
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vol. 7
151-176
EN
It’s considered that one half of all projectiles are striking surface of planets at the angle lower than 45°. Our knowledge of oblique impact events is based on computer modelling, laboratory experiments and observation of craters on the Moon, Mars, Venus and other celestial bodies. Recent discovery in northeast Poland, reveals at least four structures with features reserved for low-angle impacts. In this article we show and explain them using high-quality laser air scanning data (LiDAR) in comparison to results of experiments and similar real known objects on other planets. Also we try to verify by analyzing historical sources if multiple impact event could occur in our area and, if it was noticed and reported in the papers.
4
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Impaktyty astroblemy Ilińce, Ukraina

63%
Kosina R.
Acta Societatis Metheoriticae Polonorum
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2017
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vol. 8
73-83
EN
The complex Ilyinets crater is an example of the small impact structure formed in crystalline target rocks of the Ukrainian Shield. Its impactites are characterised by examples of metamorphosed gneisses, granites, fine-grained polymict breccia and suevites. In the breccia and suevite matrix, fluidal clasts present their earlier brecciation. Lobate contacts between quartz grains show recrystallisation by grain-boundary migration. Shock structures, PFs, PDFs and “ballen quartz” are not very frequent. The monomict suevite breccia was determined among impactites.
5
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‘Aegean’ – kolisty obszar w południowej Europie – jego geologia a największe kratery na Ziemi

63%
Walesiak T.
|
EN
Analysis of online available references suggests that circular characteristics observed around Aegean Sea in southern Europe may represent protobasin class of impact craters, which small central peak and surrounded peak ring appear to be formed by the Cyclades. Thinner crust, upper mantle deformation (uplift), recognition of basin in upper mantle re-filled with rocks having lower density than surrounding mantle, central Aegean Sea area free of sediments and almost perfect circular anomaly of density with diameter over 500 km are only few arguments which may indicate its real origin. The strongest fact standing for hypothesis of impact is presence of deep, lithospheric fracture zones with both circular and radial character, detected up to the distance of ~516 km from common geometric point of all rings (providing estimated diameter of the largest circle over 1000 km). Existence of pseudotachylite veins and breccias in central Cyclades are contributory evidence. Mélange covered by Fe-Ni rich ores in Jurassic/Cretaceous boundary, if related to impact, may give clue to explanation of localized in Europe Tithonian mass extinction event 145 Ma. However, pseudotachylites and breccias can be produced by endogenic processes (e.g., plate tectonics). A further research is required to find evidence of passage of shock wave through target rocks.
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