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GOALS AND OBJECTIVES: THE OBJECTIVE OF THE PROPOSED WORK IS TO PROVIDE ADDITIONAL EXPERIMENTAL CONSTRAINTS FOR THE FURTHER DEVELOPMENT OF A COMPREHENSIVE BAROMETRY AND THERMOMETRY OF IMPACT STRUCTURES AND SHOCKED METEORITES. THE MINERALOGICAL RECORD PRESERVED IN IMPACT CRATERS AND SHOCKED METEORITES PROVIDE A UNIQUE WINDOW INTO SOLAR SYSTEM FORMATION AND PLANETARY EVOLUTION. THE IMPACT AND EJECTION PROCESSES CAUSE DRAMATIC CHANGES IN THE MICROSTRUCTURE CRYSTAL STRUCTURE AND POTENTIALLY THE ISOTOPE COMPOSITION OF THE MINERAL ASSEMBLAGE. HENCE THE COMMONLY USED SHOCK CLASSIFICATION MODELS ASSIGNS SHOCK LEVELS FROM UNSHOCKED (S1) TO VERY STRONGLY SHOCKED (S6) BASED ON MICROSTRUCTURE AND MINERAL PHASES. THESE CLASSIFICATION MODELS ARE MAINLY DERIVED FROM CHARACTERIZATION OF METEORITES AND ROCKS FROM KNOWN IMPACT SITES AND FURTHER CONSTRAINED BY EXPERIMENTAL DATA FROM STATIC AND DYNAMIC COMPRESSION EXPERIMENTS. HOWEVER THE EXPERIMENTAL CHARACTERISTICS IN STATIC AND DYNAMIC COMPRESSION EXPERIMENTS SUCH AS INVESTIGATED TIMESCALES AND PRESSURE-TEMPERATURE COUPLING ARE NOT A DIRECT REPLICATION OF THE NATURAL SHOCK CONDITIONS. THEREFORE THE RESULTS FROM STATIC AND DYNAMIC COMPRESSION EXPERIMENTS PROVIDE UPPER AND LOWER BOUNDARIES FOR THE BAROMETRY AND THERMOMETRY OF IMPACT STRUCTURES. FOR EXAMPLE THE EXISTENCE OF HIGH PRESSURE POLYMORPHS SUCH AS RINGWOODITE MAJORITE AND BRIDGMANITE IN SHOCKED METEORITES CANNOT BE EXPLAINED FOLLOWING THE ESTABLISHED SHOCK BAROMETER AND THERMOMETER SINCE HIGH SHOCK PRESSURE RESULTING IN HIGH BULK ROCK TEMPERATURES WOULD FAVOR A BACK TRANSFORMATION TO THE RESPECTIVE LOW PRESSURE POLYMORPHS.

$268,442FY2020National Aeronautics and Space AdministrationNASA

The Research Foundation For The State University Of New York

Investigators

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