Strange Glass Spheres Found in Ancient Florida Clams Point to Meteor Strike

This at first appeared in the July/August issue of Discover journal as “Message in a Clam.” Support our science journalism by starting to be a subscriber.

In abundant fossil deposits in southern Florida acknowledged as the Pinecrest beds, historic clams sit nestled in a combine of sand and clay, waiting to convey to their tales. In 2006, Michael Meyer joined his fellow undergraduates as they searched a quarry there for the fist-sized time capsules of historic environments. The pupils ended up seeking within the clams for benthic foraminifera, single-celled organisms whose shells just take on unique shapes dependent on their environments. Coiled or straight, spiraled remaining or ideal, the foraminifera can expose what was occurring in their world three million years in the past, when the beds ended up deposited. But Meyer, now an assistant professor of Earth devices science at Harrisburg University of Science and Engineering in Pennsylvania, observed anything else in the clams, much too — however it took him in excess of a ten years to discover the significance of his area excursion uncover.

clam student project florida

(Picture: Michael B. Meyer)

In His Personal Text:

“We ended up opening these useless clams and quickly took place on all of these little spheres. I imagined, “What the heck are these?” They ended up the exact same dimension assortment as benthic foraminifera, but no just one realized what they ended up.

I collected all eighty four of them and went again to lab to procedure them. I also despatched out a lot of email messages, but people today claimed they did not believe they ended up something. Some others advised a couple of high priced analyses on exceptional products that an undergraduate simply cannot obtain. We ended up capable to check the spheres by X-ray spectroscopy about two weeks just after original discovery, but that only advised us the spheres ended up “silica abundant,” and that was it.

I stored them on a slide in a box, and for the previous 13 years, when I experienced some time, I would carry out the spheres. My colleagues who know me well would say, “How are individuals little strange spheres accomplishing?” As I matured as a researcher, I would discuss my way on to lab products when I could get some absolutely free analyses finished. 


Michael Meyer pictured. (Credit score: Michael Meyer)

Finally, in 2018, a a lot more sensitive X-ray spectroscopic analysis discovered that the spheres are microtektites: small bits of glass that kind when a meteorite slams into Earth and spews molten product in a wonderful mist.

But there are nevertheless a couple mysteries: These microtektites are large in sodium, which is abnormal mainly because microtektites are created of silica and never typically include sodium. We nevertheless simply cannot absolutely clarify that. We also never know when they ended up fashioned.

The quarry where we observed the clams has since been stuffed as section of a true estate development, so there is no way to go again and dig for a lot more. We have been inquiring area fossil hunters to look in other quarries and get this specific form of clam and sediment samples to see if we can pull out any a lot more microtektites that could possibly address these mysteries.”

— As advised to Jeanne Erdmann