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Wykorzystanie danych Numerycznego Modelu Terenu do poszukiwania i wstępnej identyfikacji struktur impaktowych

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Walesiak T.

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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.

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Dalsze badanie struktur w okolicach Wyszkowa – wyniki prac terenowych

86%

Walesiak T.

Acta Societatis Metheoriticae Polonorum

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2019

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vol. 10

168-192

EN

There are specified criteria used to verify if some geological structure was developed during hypervelocity impact. Some of them are related to the passage of a shock wave through rocks, so are considered as definitive. Porządzie, Jaszczulty & Ochudno are structures discovered in 2014 (based on LiDAR data). They have many features suggesting possible impact origin. In shape of Porządzie there can be even recognized possible traces of shock waves, similar to those present during hypersonic flow (similar to observed e.g. in an airburst shape of extraordinary bright meteors). Unfortunately, this kind of observations (morphometry) on Earth is still considered as not enough to confirm the crater. The aim of recent study was to search for additional traces, which may help to prove that mentioned structures were created during common oblique impact event. Initially there were chosen 3 locations for outcrops, but finally samples were collected from 6 smaller pits. In Porzadzie structure there were discovered cemented rocks with various shape and size (concretions or lithic, parautochtonous breccias) and 2 rocks with possibly shocked quartz, having basal sets of thin and straight lamellae. On once surface there were recognized hierarchal branched (including spoon-like) structures resembling shatter cones. In uprange, at depth of about 50–70 cm, soil was rich in small charcoal pieces (like in other relatively small craters: e.g. Campo del Cielo, Whitecourt, Kaali, Ilumetsa, Morasko). All these observations, taken together with previous results, are about to confirm impact origin of Porzadzie crater.

3

Analiza cech impaktu ukośnego na przykładzie struktur Porządzie, Jaszczułty i Ochudno

86%

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.

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3 Walesiak T.

Wykorzystanie danych Numerycznego Modelu Terenu do poszukiwania i wstępnej identyfikacji struktur impaktowych

Dalsze badanie struktur w okolicach Wyszkowa – wyniki prac terenowych

Analiza cech impaktu ukośnego na przykładzie struktur Porządzie, Jaszczułty i Ochudno