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TitleImpact cratering on Earth
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LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorGrieve, R A F
SourceA synthesis of geological hazards in Canada; by Brooks, G RORCID logo (ed.); Geological Survey of Canada, Bulletin 548, 2001 p. 207-224, https://doi.org/10.4095/212219 Open Access logo Open Access
Image
Year2001
PublisherNatural Resources Canada
Documentserial
Lang.English
Mediapaper; on-line; digital
RelatedThis publication is contained in A synthesis of geological hazards in Canada
File formatpdf
ProvinceCanada
NTS1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65; 66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560
Lat/Long WENS-141.0000 -50.0000 90.0000 41.7500
Subjectsextraterrestrial geology; structural geology; meteorite craters; craters; metamorphism, shock; frequency distributions; extinctions, biotic; structural analyses; structural features; structural basins; health hazards; Distribution
Illustrationsphotographs; aerial photographs; graphs; sketch maps
Released2001 04 01
AbstractApproximately 160 known terrestrial impact structures are distributed worldwide, with concentrations in geologically stable areas. The basic types are simple' craters, up to 4 km in diameter, with uplifted and overturned rimrocks surrounding a bowl-shaped depression, and complex' structures, generally over 3 km in diameter, with a central uplifted peak and/or ring, an annular trough, and a slumped rim. Morphology is used only to identify possible impact structures. The impact origin of smaller craters can often be determined by the presence of fragments of the impactor. At large craters, however, the impact commonly melts or completely vapourizes the impactor and verification is based on shock metamorphism. The formation of impact craters as small as 20 km reduces sunlight and disrupts temperature in a manner similar to a nuclear winter. A large impact event at the Cretaceous Tertiary (K T) boundary is the most likely cause of impactor mass extinctions that occurred at that time.
GEOSCAN ID212219

 
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