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Fossil clams contain evidence of ancient meteorite

Researchers picking through the contents of fossil clams from a Sarasota County quarry found dozens of tiny glass beads, likely the calling cards of an ancient meteorite. Analysis of the beads suggests they are microtektites, particles that form when the explosive impact of an extraterrestrial object sends molten debris hurtling into the atmosphere where it cools and recrystallizes before falling back to Earth. They are the first documented microtektites in Florida and possibly the first to be recovered from fossil shells. As part of the project, students systematically collected fossils from the shell-packed walls of a quarry that offered a cross-section of the last few million years of Florida's geological history. They pried open fossil clams, washing the sediment trapped inside through very fine sieves. The researcher was looking for other tiny objects -- the shells of single-celled organisms known as benthic foraminifera -- when he noticed the translucent glassy balls, smaller than grains of salt. The researcher thinks the microtektites are the products of one or more small, previously unknown meteorite impacts, potentially on or near the Florida Platform, the plateau that undergirds the Florida Peninsula.

Visit Website | Image credit: Meyer et al. in Meteoritics and Planetary Science