Lecture_07 - HUNDREDS OF TONS PER DAY MOSTLY...

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LECTURE 7: METEORITE IMPACTS 1.0 METEORITICS METEOROID METEOR (IONIZES) SHOOTING STARS SHOWERS METEORITE ANN ARBOR 1.1 COMPOSITION AND CLASSIFICATION STONES MOST ABUNDANT (94%) MAINLY SILICATES, SOME CARBONACEOUS CHONDRITES CONTAIN CHONDRULES (GLASSY SPHERES) UNALTER AND UNDIFFERENTIATED CONDENSED EARLY MOST ABUNDANT ACHONDRITES DO NOT CONTAIN CHONDRULES ALTERED AND DIFFERENTIATED RESEMBLE VOLCANIC ROCKS FROM THE MOON
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STONY-IRONS BRECCIA MIXTURE OF STONY AND METALLIC MATERIALS IRONS VERY DENSE NICKEL AND IRON WIDMANSTÄTTEN PATTERN 1.2 ORIGIN OF METEORITES ASTEROID BELT - MAIN SOURCE 100,000 ASTEROIDS (4,000 NAMED) DIFFERENTIATION FRAGMENTATION SOME DERIVED FROM THE MOON AND MARS COMETS -MINOR SOURCE ICY MATERIAL AND SILICATE DUST ECCENTRIC ORBITS COMET NUCLEUS, COMA, PLASMA TAIL AND DUST TAIL CAN SPLIT APART APOLLO OBJECTS 150 APOLLO (EARTH CROSSING) ASTEROIDS >1 KM DIAM. 300,000 EARTH CROSSING OBJECTS > 100 M DIAMETER 35 NEW APOLLO OBJECTS IDENTIFIED EACH YEAR 1.3 IMPACT EVENTS
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METEORITE FLUX
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Unformatted text preview: HUNDREDS OF TONS PER DAY MOSTLY MICROMETEORITES >1 M DIAMETER HIT ABOUT 1 PER YEAR (CAUSES CRATERING) 100 M TO SEVERAL KM DIAMETER (ABOUT EVERY MILLION YRS) VELOCITIES BETWEEN 4 AND 40 KM/SEC CRATERED SURFACES ON EARTH >200 IMPACT CRATERS HAVE BEEN IDENTIFIED SEQUENCE OF EVENTS IMPACT AND EJECTA COMPRESSION DECOMPRESSION SIMPLE CRATERS (<5 KM, METEOR CRATER, ARIZONA) COMPLEX CRATERS (>3 KM, UPHEAVAL DOME, UTAH) 1.4 IMPACTS AND MASS EXTINCTION IMPACT RESULTS OF A 10 KM DIAMETER METEORITE BLAST WAVE (1,000 TIMES YIELD OF ALL H-BOMBS) VAPORIZATION OF ROCK AND WATER EARTHQUAKES TSUNAMIS GLOBAL FIRES GLOBAL DARKNESS EXTREME COLD ACID RAIN (NO) 1.5 GEOLOGIC RECORD OF MASS EXTINCTIONS MASS EXTINCTION AT K-T BOUNDARY (96%) IRIDIUM (Ir) ANOMALY, SOOT, SHOCKED MINERALS, SPHERULES IMPACT OR VOLCANISM? CHICXULUB CRATER, MEXICO EXTINCTION OF DINOSAURS? PERIODICITY OF EXTINCTIONS 26 MILLION YEAR INTERVAL?? FUTURE IMPACTS RESULTING IN MASS EXTINCTIONS 1 IN 10,000 CHANCE IN HUMAN LIFE-SPAN...
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Lecture_07 - HUNDREDS OF TONS PER DAY MOSTLY...

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