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Index ageing of meteorites, 14C terrestrial ages and infall rate Barringer crater 111 75-91 bolides, mass extinctions 219-22, 265-7, 270 age distributions 78, 87-8 intensity 221 Allan Hills Icefields 79-83 see also asteroids; comets; impact events Elephant Moraine 83, 86-7 Bosumtwi crater, Ghana, impactites 144-5 production rate and interpretation 76-78 Brent impact structure 111 weathering and stable isotopes 88-9 Bushveld Complex, Vredefort Dome impact structure 26AI/53Mn ratio, Mundrabilla iron meteorite 62 146-8, 195-6 Algerian Sahara, Reg el Acfer, meteorite accumulations 46 carbon geochemistry Allan Hills Icefields allotropes 205-14 Antarctic H chondrites 48 diamonds 207-14 Far Western Icefield 85-6 fullerenes 206-7 meteorite 14C terrestrial ages and infall rate, Main 14C terrestrial ages, Antarctica 75-91 Icefield 79-83, 95-102 saturated activities 14C, 20-50 cm meteorites 78 meteorite recovery 47-8 terrestrial impact craters 205-16 meteorite stranding 96 cenotes 158-9, 161-2 meteorite weathering 49-51, 88-9, 98-102 Chicxulub impact structure, Mexico 4, 155-93 14C data 88-9 anhydrite as source of sulphur dioxide 122 6aSo and 613C 88-9 comet as impactor 166 Middle Western Icefield 85 Cretaceous-Tertiary (K-T)boundary 122, 148, 177, Near Western Icefield 85 205 oxidation-frequency R(n) plot, vs hot desert areas flooded sinkholes (cenotes) 158-9, 161-2, 178 49-50 map 178 R(t) plot, terrestrial age vs ferric iron 45, 48 mapping with gravity and seismic data 155-75 see also Antarctica crater structure mapping 156-62 ammonite controversy, Cretaceous-Tertiary (K-T) horizontal gravity anomaly gradient 156-9 boundary 235-7 impact and environmental effects 167-70 anoxia and transgression 269-71 transient cavity size, impact energy 162-7 ANSMET expeditions, Antarctica 100 passive seismic array 177-93 Antarctica data acquisition and event location 178-80 carbonate weathering products 78 Rayleigh-wave dispersion study 180-7 Elephant Moraine Icefield, 14C terrestrial ages teleseismic receiver function analysis 187-91 86-7 chondrites H chondrites, Thiel Mountains 48 H group 63 location map 76 M6ssbauer measurements 45, 48 meteorite age distributions 87-8 oxidation and terrestrial age 45-6, 48-51 meteorite flux 48, 93-104 climate change, mass extinctions 268 determinations from fireballs 93-4 cometary cratering rate, impact structures 15 locations 95 comets meteorite pairing 98-9 dark 11 17 recovery conditions 94-102 evolution 13 terrestrial age dating 86-7, 95-7 flux modulation by Galaxy 20-1 time changes in Antarctica 99-102 Hale-Bopp 19 weathering and differential survival 49-51, 88-9, impacts on Earth 98 Chicxulub impact structure, Mexico 166 wind-driven rock race 98-9 cumulative frequency by size 37 Archaean impact events 121 major agents of crater formation 2 asteroids observed, long and short periods 11-12 annual impacts, by size 37 short-period C-type 101 Halley-type objects 11-17 near-earth (NEAs) 11-17, 36-8 Jupiter family 9, 11-17 major surges 9 small bodies 11 Australasian tektites, impactites 142-4 comminution 197-8 Australia Cook 007 H4 group chondrite 63 Nullarbor Region, meteorite flux 59-73 crater-producing bodies see asteroids; comets; Proterozoic cratering rate, compared with Moon 7 impactors Western Australian Museum (WAMET) 59 Cretaceous-Tertiary (K-T) boundary 19, 105-6, 177, automated pairing studies 52-6, 98-9 205 genetic algorithm (GA) 54-6 ammonite controversy 235-7 new approach 43-56 Chicxulub impact structure 122, 177, 205 Nullarbor Region 59, 63-7 iridium anomaly 19 276 INDEX Cretaceous-Tertiary (K-T) boundary (continued) Ghana, Bosumtwi crater impactites 144-5 major impact evidence 121-2 Gosses Bluff impact structure 112 planktonic foraminiferal controversy 231-5 Goulds belt complex 21 soot, wildfires 122, 206-7 Halley-type comets 11-17 vertebrate extinction Halley-type orbits, frequency 11-17 dinosaurs 253-5 Hawke Bay Event 269 gradualistic and impact models 25~3 Holmes cycle, Galactic periodicity 19-20, 28 vertebrate record 247-52 hypervelocity impact see impact structures Darwin crater and impact glass, impactites 141 2 impact craters see impact structures decay constant 45-7 impact structures 105 10 deserts see Acfer; Nullarbor Region, Australia; analysis, craters (age vs diameter) 25 Roosevelt County carbon geochemistry 205-16 diamonds carbon allotropes 214 Popigai crater, North Siberia 207-10 fullerene molecule C60 206 7 Ries crater, South Germany 210-14 Popigai, North Siberia, Russia, impact crater other craters 214 diamonds 207-10 digital imaging of meteorite photomicrographs for Ries, South Germany, diamonds and silicon automated pairing 52-6 carbide 210-14 dinosaurs see vertebrate extinction comparison with nuclear explosion 31, 34-6 correlated with mass extinctions 27 Earth, bombardment periodicity 21 crater scaling law 13-17 Earth evolution 119-25 craterforms 110-15 earliest (unknown) 119-21 cross-section schema frequency of K-T-sized events 123 complex 112 later (known) 121-5 large 201-2 Moon formation hypothesis 120 1 simple 111 Edgeworth-Kuiper belt 11-17 tranient and disruption diameters 163 E1 Kef blind test, foraminifera 232-5 whole crustal model 164 energy release Darwin crater and impactites 141-2 nuclear test craters 35 energy~liameter equation 34-6 vs crater diameter 35 erosion 32-3 European Meteorite research (EUROMET) 59 events, time-scales 124-5 extinctions see mass extinctions hypervelocity impact 195-204 Fermor Lecture Meeting 1 comminution 197-8 fireballs, meteorite flux, Antarctica 93-4 compared to nuclear explosions 34-5 flood basalt eruptions, bolide events and sea-level localized shock and friction-induced melting changes, intensity of mass extinctions 22, 219 20 198-204 flux estimation 3 pseudotachylytes 195-203 Antarctica 47 56, 93 104 shock veins 200-3 Allan Hills 43-56 impact record 7, 106 10 determinations from fireballs 93-4 large, increase in rate of production 7 calculations from decay rates 43-58 list, basic characteristics 108 comets 20-1 mass distribution equation 36-9 evidence and consequences 105-31 North American Craton 32-3 hot desert periodicities 20 Nullarbor Region, Australia 59-73 rate Roosevelt County 46, 61, 101-2 cometary cratering rate 15 Sahara 44-7, 61 cratering rate equation 31-4 Flynn Creek crater 36 estimated, Earth and Moon 7-8 foraminifera late heavy bombardment 8 Cretaceous-Tertiary (K-T) boundary 230-5 long-term variations 7-9 El Kef blind test 232-5 production of large craters 7 Lazarus taxa 230 production rate 33-4 friction-induced melting, hypervelocity impact size-frequency distribution 109 structures 198-200 related events 105-31 Frood-Stobie ore body 196 Cretaceous-Tertiary boundary 105-6 Earth evolution 119-25 Galactic periodicity 19-29 earliest (unknown) Earth 119-21 hypothesis 22-3 later (known) Earth 121-5 Galactic tide, Oort cloud 20 marine invertebrate extinctions 217-46 genetic algorithm (GA), automated pairing of Moon formation hypothesis 120-1 meteorites 54-6 shock metamorphism 115-17 Germany, Ries crater 118, 210-14, 266 size-frequency distribution 109 INDEX 277 stratigraphic record l 18-19 taxa, victims and survivors 228 terminology 106 taxonomic victims and survivors 228 terrestrial marine regression, mass extinctions 268 70 inferred impactor types 138-9 mass distribution location map 107 crater-producing bodies 31-42 number known 133 shower falls 65~ impactites 133-53 equation, asteroids and comet impacts 36 40 Australasian tektites 142 4 Roosevelt County, New Mexico 101-2 Bosumtwi crater 144-5 mass extinction events 217-46, 259-74 Darwin crater and impact glass t41 2 anoxia and transgression 269-71 Ivory Coast tektites 144-5 'big five', extinction rates 260 meteoritic components 133 53 biostratigraphic data 229 31 identification problems 137-40 bolide impact 265-7 platinum group elements (PGEs) 135--6 causal factors 265 Re~Os analyses 140-1 causal mechanisms 225-6 siderophile element analyses 134-6 correlation with causal events 218-24 Mexico, Chicxulub 148 summary 270 South Africa climate change 268 Saltpan crater 145-6 correlated with impact structures 27 Vredefort 146-8 episodes 259 impactors 1, 9 gradualistic and impact models 252-3 cometary capture 11 identification by selectivity criteria 224-9 kinetic energy E 39, index, asteroids and comets 40 intensities 26l-2 mass distribution 31-42 vs bolide events, flood basalt eruption events and crater diameter vs energy release 35 sea-level changes 219-20 cratering rate equation 31 4 kill curve, marine species 266 energy-diameter equation 34-6 marine regression 268-9 mass distribution equation 36-9 periodicity 261-5 see also flux estimation Permian 5 impacts on Earth see impact structures possible causal factors 265 invertebrate extinctions see marine invertebrate taxa, victims and survivors 228 extinctions volcanism 267 iridium, abundances, range 135 vs sea level (Hallam) 269 iridium anomaly, KT boundary 19, 265 see also Cretaceous-~ertiary (K-T) boundary; iron meteorites, regional deficiencies, causes 67 70 marine invertebrate extinctions; vertebrate Ivory Coast tektites, impactites 118, 144-5 extinctions Melosh relationship 35 Jupiter family comets 11-17 meteorite flux see flux estimation Meteorite Observation and Recovery Project (MORP) K-Ar and Ar Ar dating 110 camera network 44, 60 K-T see Cretaceous-Tertiary boundary flux estimation 43-4 Lampson cube-root law 34 meteorites, type frequency 67-70 Lazarus taxa Mexico, Yucat~n see Chicxulub impact structure foraminifera 230 molecular clouds, giant, penetration by Sun 21 Signor-Lipps effect 230 1 Montagnais structure,
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