Biology student, Mike Meyer, spent the summer of 2006 prying open and rinsing fossilized clams in a Sarasota County, Florida quarry. Students were looking for tiny organisms called benthic foraminifera. Instead, Meyer found dozens of small, translucent glassy balls. Grains of sand were expected, but not the tiny, perfect spheres they found.
Clam time capsules
Most of the spheres were found inside fossil southern quahogs. The Shell Museum says southern quahogs are a large member of the Venus Clam family that may grow to six inches in size. They are often found in shallow, sandy-mud flats of bays and protected areas.
Sediment and particles that accumulated in clams as they died were sealed up as more and more layers of sediment accumulated atop them over time. Essentially, the quahogs that were sealed up under layers of sediment were ancient time capsules.
For a decade, Meyer didn’t have the time to look into exactly what he’d found.
Extraterrestrial objects and hypervelocity impacts
Analysis years later suggests those beads were microtektites, the microscopic version of tektites. According to sciencedirect.com, tektites are glass objects created during melting and vaporization of Earth’s crust during high-velocity impacts. One clue was the trace presence of exotic metals that showed up in tests of the spheres. According to the Florida Museum, microtektites are:
…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.
So, how ever did extraterrestrial beads end up inside clam shells on the walls of a Florida quarry?
Meyer speculates that the microtektites he found are byproducts of small meteorite impacts on or near the Florida Platform. The Florida Platform is the plateau that lays beneath the Florida Penninsula. They are the first documented microtektites in Florida, and may also be the first microtektites ever found in fossilized shells.
Beads formed when the explosive impact of the meteorite sent debris hurtling into the atmosphere where it cooled and recrystallized before falling back to Earth and being washed into a quahog for millennia, only to be discovered by students millennia later.
Meyer’s testing of the glassy beads revealed a puzzling result. The beads contained high amounts of sodium, which distinguished them from more common impact debris. Salt is a highly volatile compound and is typically not found in impact debris, because it usually boils off when the debris is thrown into the atmosphere at significant velocities.
Why does that salty oddity matter? In an interview with the Florida Museum, Meyer explained: “This high sodium content is intriguing because it suggests a very close location for the impact. Or at the very least, whatever impact created it likely hit a very large reserve of rock salt or the ocean. A lot of those indicators point to something close to Florida.”
Meyer and others published their findings in a paper entitled “A first report of microtektites from the shell beds of southwestern Florida”.
Millions of years old
Dating of the microtektites remains to be conducted, but co-author Roger Portell suggests the beads may be two to three million years old. Portell, Invertebrate Paleontology collections director at the Florida Museum of Natural History, was the leader of the summer fieldwork project Meyer was participating in 2006 when the beads were found.
It’s thought that there are many more microtektites out there to be found. The authors of the paper encourage fossil collectors to watch out for them. But there’s no point going back to the quarry where Meyer’s adventure in extraterrestrial-pearls-in-claims journey began. It’s now a housing development.