Earle McBride and Dane Picard were travelling across France doing geologic field work in 1988 when they took time out to play tourists at Omaha Beach, site of one of the most ferocious battles during the D-Day invasion more than 40 years earlier. It was a miserably cold and blustery day. They tarried just long enough to scoop a sample of beach sand into a little baggie. McBride, a professor emeritus in the Jackson School of Geosciences at The University of Texas at Austin, collects sand pretty much any chance he gets. By analysing sand from modern dunes, beaches and rivers from a wide range of sites around the world, he can link the mineral compositions of ancient sandstones to the kinds of environments that forged them. A few years after the French trip, he put the beach sand under a microscope and discovered tiny metal shards mixed in with the ordinary bits of quartz and other materials that he expected to see. Those shards turned out to be shrapnel from the famous World War II invasion. On closer examination, he also found iron and glass beads that resulted from the intense heat unleashed by explosions in the air and sand. Read more