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Wyszukujesz frazę "crater field" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Wykorzystanie danych Numerycznego Modelu Terenu do poszukiwania i wstępnej identyfikacji struktur impaktowych
Use of the digital elevation models (DEM) as a tool for searching and preliminary identification of impact structures
Autorzy:
Walesiak, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/1033155.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Meteorytowe
Tematy:
cardioid pattern
crater field
impact structures
morphometry
oblique
Opis:
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.
Źródło:
Acta Societatis Metheoriticae Polonorum; 2020, 11; 110-124
2080-5497
Pojawia się w:
Acta Societatis Metheoriticae Polonorum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Kaali crater field and other geosites of Saaremaa Island (Estonia): the perspectives for a geopark
Autorzy:
Raukas, Anto
Stankowski, Wojciech
Powiązania:
https://bibliotekanauki.pl/articles/94342.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
geopark
geosites
meteorite-crater field
Saaremaa Island
Estonia
geostanowiska
Opis:
The Island of Saaremaa in Estonia offers highly spectacular geological features that belong to the most interesting in the Baltic Sea area. A unique geological monument on the island is the Kaali meteorite-crater field, formed by nine meteorite impacts. There are also attractive coastal cliffs, huge erratics, alvars (limestone areas covered by a very thin soil) and well-developed glacial and marine landforms. Limestone cliffs and shingle beaches abound with Silurian fossils and offer great opportunities to fossil collectors. The island is a prospective geopark. During the past few years, the geology of the island has become an intensely studied object of Estonian and Polish geologists.
Źródło:
Geologos; 2010, 16, 1; 59-68
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Materia pozaziemska w otoczeniu kraterów meteorytowych Kaali (Estonia)
Extraterrestrial material from the surroundings of the Kaali meteorite craters (Estonia)
Autorzy:
Uścinowicz, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/94227.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
materia pozaziemska
kratery Kaali
sferule
Estonia
extraterrestrial materials
Kaali crater field
spherules
Opis:
Kratery meteorytowe Kaali (wyspa Saaremaa, Estonia) stanowią unikatowe miejsce w Europie, nie tylko ze względu na wyjątkową formę wykształcenia, ale także dostępność do badań metalicznej materii pozaziemskiej. Podczas badań terenowych prowadzonych w maju 2004 roku autor zgromadził próbki osadów, które posłużyły do badań drobnej frakcji materii magnetycznej występującej w obrębie kraterów meteorytowych Kaali. Na podstawie morfologii, cech powierzchni i składu chemicznego wyselekcjonowanych ziaren magnetycznych wyróżniono cztery grupy materii: (1) kosmiczne kulki zbudowane z tlenku żelaza, zawierające nikiel, (2) kulki węglowe, które wstępnie zaklasyfikowano jako antropogeniczne, (3) kulki krzemianowe interpretowane jako zestalone krople wymieszanej materii ziemskiej i pozaziemskiej, i (4) płytki zbudowane z tlenku żelaza, pozbawione niklu, które zinterpretowano jako zwietrzałe pozostałości materii pozaziemskiej. Opis morfometryczny kraterów Kaali został sporządzony na podstawie danych literaturowych oraz wizji lokalnej przeprowadzonej przez autora.
The Kaali meteorite crater field is a unique place in Europe, not only because of its morphology but also because of the presence of large amounts of extraterrestrial material. During field work in May 2004, samples were collected at this site with the objective to study magnetic fines. Based on morphology, surface features and chemical composition of the selected magnetic material, four groups of spherules and plates were distinguished: (1) Ni-bearing Fe-oxide spherules of cosmic origin, (2) carbon spherules tentatively classified as anthropogenic, (3) silicate spherules interpreted as solidified droplets of mixed terrestrial and extraterrestrial matter, and (4) Ni-free Fe-oxide plates interpreted as weathered remnants of extraterrestrial material. The Kaali crater site is described morphologically on the basis of literature and the author’s own observations.
Źródło:
Geologos; 2008, 14, 2; 211-219
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kratery Morasko – obrona hipotezy ukośnego impaktu w kontekście dostępnej wiedzy i wyników badań
Morasko craters – in defense of oblique impact origin based on knowledge and research
Autorzy:
Walesiak, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/1830330.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Meteorytowe
Tematy:
bilateral symmetry
crater field
elliptical craters
forbidden zone
meteorite Morasko
oblique impact
Opis:
Over 2 years ago there was published an article (Bronikowska 2018a) challenging some results of research related to Morasko meteorite fall. Those results are huge problem for scientists who are not able to explain them using simplified models and maybe do not want to admit that some assumptions should be verified and redefined. One of hypothesis discussed in the paper was article manifesting that Morasko craters were created during oblique impact (Walesiak 2017) and that initial trajectory can be estimated by elongation of almost all cavities, their bilateral symmetries according to longer axis and observed asymmetries of rims. By comparison to Campo del Cielo craters Walesiak suggested that impact angle could be very shallow (10–20°), as ellipticity of all smaller Morasko structures is approx. 1,3. Further analysis of topography in neighborhood of Morasko revealed that there may exist more impact craters around this area, which may explain discovery of two iron meteorites near Oborniki village (17 km NW from Meteorite Morasko Restricted Area), unfortunately lost during World War II. In fact, Bronikowska confused definitions “oblique impact” and “elliptical craters”, what can be supported by given references (Elbeshausen et al. 2009) confirming Walesiak hypothesis. Unfortunately, this misunderstanding touches also another article of this author (Bronikowska et al. 2017), where obliquity was neglected. However, estimated during that modeling pre-impact angle (30–43°), according to known definitions written in many publications, should be classified as oblique impact. All elongated craters, as well as morphology of the largest structure in Meteorite Morasko Restricted Area suggest impact from NW while during reconstruction of meteoroid parameters Bronikowska assumed impactor coming from NE (based on existing strewn field). Considering not clear relation between meteorites and craters (e.g., lack of findings in cavities, relatively poor number of shrapnel fragments around structures and possibility that craters may be much older than fall of meteorites), it may be not enough reliable justification. Even if relation exists, example of Whitecourt (with distribution of meteorites downrange), compared with abundance of Morasko shrapnel fragments collected hundreds of meters NE from Restricted Area, undermines parameter used in modelling. Also, single fragmentation is doubtful, concluded after unreasonable omitting known craters outside Restricted Area (e.g., crater no 8 described by Pokrzywnicki (1964) and structure no 9 mentioned by Hodge (1994)). Finally, use of iSALE-2D shock physics code (valid for vertical impacts only) for modelling of elliptical craters formed during highly oblique impact (angle lower than 12°), even considering vertical component (which approximation is only applicable for impact into materials with a friction coefficient of about f=0,7 with no or very little cohesion) (Elbeshausen et al. 2009), also should not be considered as proper applied method leading to get valuable results. In this article there is proposed new strewn field definition for Morasko meteorite, based on elongation of all known and unconfirmed (yet) craters. Surprisingly, estimated (redefined) pre-impact trajectory gives convincing explanation for bilaterally symmetrical distribution of documented findings.
Źródło:
Acta Societatis Metheoriticae Polonorum; 2021, 12; 108-128
2080-5497
Pojawia się w:
Acta Societatis Metheoriticae Polonorum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Imilchil meteorite strewn field and Isli-Agoudal craters
Autorzy:
Nachit, H.
Ibhi, A.
Vaccaro, C.
Powiązania:
https://bibliotekanauki.pl/articles/411597.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Meteorite
strewn field
Isli
Agoudal
Impact crater
Morocco
Opis:
New meteorite prospections at different places in the region of Imilchil showed that (1) besides the Ataxite of Tasraft all the other collected specimens belong to the same and only IIAB iron mother meteorite (2) the strewn field of the meteorite has a length of about 38 km into north-south direction (3) the small crater of Agoudal as well as the impact crater of Isli are situated on a parallel north-south axis, if not put together with the strewn field of the Imilchil meteorite (4) these two structures might be the result of the fall of the same and only mother meteorite of the IIAB type.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 11; 65-71
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The first Polish tektites: preliminary SEM investigation
Autorzy:
Brachaniec, T.
Szopa, K.
Karwowski, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/100790.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Śląski. Wydział Nauk o Ziemi
Tematy:
tektyt
mołdawit
Dolny Śląsk
Polska
tektite
moldavite
strewn field
crater
Ries
Polska
Opis:
In Lower Silesia, the first Polish moldavites were discovered. To recognize the primary chemical composition and check the morphology of investigated material SE and BSE images were used. The samples show presence of vesicles, which are one of the most typical features of tektite glass. Referring to the preliminary EDS results and comparing them with literature data, it can be assumed that in all cases the base material for all known moldavites was the same.
Źródło:
Contemporary Trends in Geoscience; 2013, 2, 1; 18-21
2299-8179
Pojawia się w:
Contemporary Trends in Geoscience
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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