North American Overview
Map shows currently known distribution of nanodiamonds in Younger Dryas Boundary sediments across North America: (1) Murray Springs, Arizona: 200 parts per billion; (2) Bull Creek, Okla.: 100 ppb; (3) Lake Hind, Manitoba, Canada: 70 ppb; (4) Chobot, Alberta, Canada: 10 ppb; (5) Gainey, Mich.: 3,700 ppb; (6) Topper, SC: 108 ppb. In transmission electron microscopy photomicrographs, diamonds are paired with associated selected area diffraction patterns of carbon spherules from the Chobot (A and B) and Topper sites (C and D). Arrows on photomicrographs highlight examples of diamonds within the amorphous carbon matrices of spherules. Arrows on SADPs are indexed d-spacings (in angstroms). (Image courtesy of AAAS; map by Jake Bartruff)