THE EFFECT OF GRIND TIME ON THE CRYSTAL LATTICE OF DOLOMITE AND THE IMPLICATIONS FOR SHOCK METAMORPHIC STUDIES OF IMPACTS INTO CARBONATE TARGETS
This study assessed the potential effects of grind times on diffraction peaks in unshocked dolostone samples as a means of providing insight into this problem. A sample of the Neoproterozoic Beck Spring Dolomite, Inyo County, CA was cut into 6 aliquots, ground by using a mechanical pulverizer in variable grind times (ranging from 3 to 18 minutes) in order to characterize potential variations in X-ray diffraction peaks with grind time.
Diffraction peaks display an overall trend of decreasing intensity and increasing peak width with increasing grind time. There is a 55% decrease in intensity observed between aliquots ground for 3 minutes and 15 minutes respectively. However, this trend is not systematic among all aliquots, as there is only a 29% decrease observed from 3 to 18 minutes, which may be due to compositional variations within portions of the sample itself. Preliminary results suggest that sample processing using a mechanized pulverizer does have the potential to deform the dolomite lattice, which is represented by broadened X-ray diffraction patterns and to affect our ability to assess the magnitude of shock metamorphism in carbonate rocks.