Measurement of In-Situ Shock Effects in Carbonate Rocks
Abstract
Detailed X-ray analyses of core samples taken directly beneath Cactus crater revealed a consistent transition from high to low Mg calcite, thus indicating retention of pre-impact stratigraphy and providing strong evidence for the absence of a fall-back breccia lens thicker than about 1 m. A downward displacement of 4 to 8 m was determined by comparing the level of the high to low Mg transition in cores taken directly beneath and outside the crater. Detailed examination of the outside, i.e. control, core samples from the critical transition interval, planned for future investigations, should allow better resolution of the amount of downward displacement of the rocks in the floor of Cactus crater as well as lending insight into the mode of in situ deformation beneath crater. We have also continued our research on identifying and applying methods of measurement of shock-induced deformation, and relating, via laboratory and field shock loading, observed shock effects to the shock histories of carbonate rocks from explosion and impact craters. During the last 6 months, we have concentrated on developing the method of peak broadening measurements in X-ray diffractometer spectra. A consistent and reproducible increase in peak widths with increasing shock pressure was observed in aragonite shocked in the laboratory and in nuclear and high explosive blasts.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 29, 1980
- Accession Number
- ADA095389
Entities
People
- J. Vizgirda
- T. J. Ahrens