Microstructural Characterization of TiO2-II in the Chicxulub Peak Ring

Schmieder, Martin ; Erickson, Timmons M ; Kring, David A

关键词: MICROSTRUCTURE;    TITANIUM OXIDES;    METEORITE CRATERS;    CORE SAMPLING;    RAMAN SPECTROSCOPY;    ELECTRON DIFFRACTION;    BACKSCATTERING;    THERMAL SHOCK;    METAMORPHIC ROCKS;    GRANITE;   

RP-ID  :  JSC-E-DAA-TN64829

美国|英语

来源: NASA Technical Reports Server

【 摘 要 】

The peak ring of the approximately 180 kilometer-diameter Chicxulub impact crater on the Yucatan Peninsula, Mexico, was recently drilled during IODP-ICDP (International Ocean Discovery Program-International Continental Scientific Drilling Program) Expedition 364, producing core M0077A. The new core provides insights into the anatomy, composition, tectonic deformation, shock metamorphism, and post-impact overprint of crater-filling impactites and crystalline basement rocks. The basement rocks were shocked to approximately 12.5-17.5 gigapascals, uplifted, and hydrothermally altered. This study presents a combined Raman spectroscopic and electron backscatter diffraction (EBSD) study of TiO2-II, a high-pressure polymorph of TiO2 with an alpha-PbO2 structure (orthorhombic; space group Pbcn; density 4.34 grams per cubic centimeter, in shocked granitoid rock of the Chicxulub peak ring.