Korrelation von Gravimetrie und Bathymetrie zur geologischen Interpretation der Eltanin-Impaktstruktur im Südpazifik
Meteorite impacts are subject of extensive scientific research because of their immense environmental influence. Most detected impacts are localised on continental or sea areas with low water depth. Oceans cover major part of the earth's surface (71%) which have an average depth of approximatel...
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| Other Authors: | , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | German |
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Universität Bremen
2007
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| Online Access: | https://media.suub.uni-bremen.de/handle/elib/2528 https://nbn-resolving.org/urn:nbn:de:gbv:46-diss000110876 |
| Summary: | Meteorite impacts are subject of extensive scientific research because of their immense environmental influence. Most detected impacts are localised on continental or sea areas with low water depth. Oceans cover major part of the earth's surface (71%) which have an average depth of approximately 3800 meter. Therefore the first and only found deep sea impact, the Eltanin Impact, is regarded to be a special one.In 1981 Frank T. Kyte discovered iridium traces in sediment cores, which were sampled during 'USNS Eltanin' cruise in 1960. To explore the causing meteorite impact in more detail, the Alfred Wegener Institute for Polar and Marine Research exerted two expeditions to the assumed impact area in 1995 und 2001. On bord the research vessel 'Polarstern' numerous geophysical and geological samplings were accomplished. Gravity corer, multi corer, sediment echo sounder and multibeam echo sounder provided results about the seabed, seismic, magnetic and gravimetric measurements delivered insight into the lower crust. Using geologic sampling and stratigraphic analysis the impact event could be dated to 2.15 million years and the diameter of the impact estimated to be larger than one kilometer. More detailed predications concerning elevation angle, impact velocity, and other parameters particularly the spezific position of the impact center could be determined only approximately by now. To verify these topics geophysical data are used in this thesis to study if the meteorite impact has affected the seabed and left deformations and structures in the crust. In the introductory chapter the basics of crater forming caused by meteorite impacts are briefly explained and the peculiarities of the Eltanin deep sea impact emphasised. The relating geological boundary conditions and settings of the South Pazific and the impact area are addressed in chapter two. Additional geophysical background knowledge concerning potential field theory, correlation of bathymetry and gravity as well as their geological relation are explained in ... |
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