نتایج جستجو برای: impact crater
تعداد نتایج: 763604 فیلتر نتایج به سال:
Introduction: Small impact events resulting in simple impact structures <100 m in diameter are common features recorded on the solid surfaces in our Solar System. Such structures are rare in Earth's impact cratering record and most are typically heavily modified by subsequent erosion or are found in remote locations. The recently discovered Whitecourt Meteorite Impact Crater (WMIC) provides sig...
Aktmct-A new variety of impact giass has been discovered at Zhamansbin impact crater (U.S.S.R.). The crater has been known as the source of different impact glasses such as irghizites and Si-rich zhamanshinites @-rich varieties) and Si-poor (andesitic) zhamanshinites. The newly discovered impact glass is ofdistinct blue color and shows a layered structure with numerous small vesicles. The blue ...
Thermochemical models have predicted that Ceres, is to some extent, differentiated and should have an icy crust with few or no impact craters. We present observations by the Dawn spacecraft that reveal a heavily cratered surface, a heterogeneous crater distribution, and an apparent absence of large craters. The morphology of some impact craters is consistent with ice in the subsurface, which mi...
available online at http://meteoritics.org Drill core LB-08A, Bosumtwi impact structure, Ghana: Petrographic and shock metamorphic studies of material from the central uplift Ludovic FERRIÈRE1*, Christian KOEBERL1, and Wolf Uwe REIMOLD2 1Department of Geological Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria 2Mineralogy, Museum of Natural History, Humboldt University, ...
The Ries Crater was formed about 12 million years ago, 120 km northwest of Munich in the district of Donau-Ries. The crater is estimated to have had a diameter of approximately 24 kilometers. In this report we discuss the preand post-impact structure of the crater site, and in particular try to investigate whether or not the Ries Crater shows evidence of structural uplift, a characteristic of m...
Shuttle Radar Topography Mission (SRTM) and Ground Penetrating Radar (GPR) data collected over an area north of the town of Hico, central Texas, have been used to map disturbances in the surface topography and subsurface stratigraphy. The Radar topography results confirm the presence of multiple rings suggestive of an impact crater. Correlation between the orbital SRTM and on-the-ground GPR fie...
The current morphology of the Martian lithospheric magnetic field results from magnetization and demagnetization processes, both of which shaped the planet. The largest Martian impact craters, Hellas, Argyre, Isidis and Utopia, are not associated with intense magnetic fields at spacecraft altitude. This is usually interpreted as locally nonor de-magnetized areas, as large impactors may have res...
available online at http://meteoritics.org 1495 © Meteoritical Society, 2004. Printed in USA. Shocked rocks and impact glasses from the El’gygytgyn impact structure, Russia Eugene P. GUROV1 and Christian KOEBERL2* 1Institute of Geological Sciences, National Academy of Sciences of the Ukraine, 55b Oles Gontchar Street, Kiev 01054, Ukraine 2Department of Geological Sciences, University of Vienna,...
Introduction: We have used the Ansys Inc. AUTODYN ® software [1] to hydrodynamically model small particle impacts into aluminium (Al) foil, under the conditions of the Stardust encounter with comet 81P/Wild 2 [2] (i.e., normal incidence, 6 km s -1 ). We compare results of impact models, based on carefully defined particle structures, with three-dimensional (3D) crater shapes reported from Stard...
Introduction: Giordano Bruno (GB) crater is among the youngest large lunar impact craters (22 km diameter at 36°N, 103°E (Fig. 1)). Its crisp morphology, extensive ray system, and spectral properties imply a young age (<<1 by). Spectral data [1, 2] indicate the ray material is immature having an optical maturity index, calculated from the Clementine 950/750 nm ratio [2, 3] of ~0.27. It was sugg...
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