Under intense pressure the crystalline structure of quartz can become deformed to create “shocked quartz,” which emits red light when excited by the electron beam in a scanning electron microscope (SEM). Additionally, the black lines observed on these shocked quartz grains indicate planar deformation features, or shock lamellae. Shocked quartz is specific to large meteorite impacts or nuclear-scale blasts, as they appear at pressures greater than 200 kilobars. This amount of pressure is equivalent to the weight of a 1,243-mile (2,000-kilometer) column of water. 

To confirm the black lines observed in the SEM are amorphous (non-crystalline), researchers at the UO utilized a high-resolution transmission electron microscope (TEM) to observe the scattering angles of the electron beam as it interacted with the amorphous regions (yielding no diffraction spots) and the bulk quartz crystal (which yielded bright diffraction spots from interacting with the crystalline plans of the grain.)

The imagery work was performed at the Center for Advanced Materials Characterization in Oregon (CAMCOR) by Kurt Langworthy (SEM imaging), Josh Razink (TEM imaging), and Valerie Brogden (focused ion beam sample prep for TEM).

— Office of the Vice President for Research and Innovation