73.8 gram Bediasite core from The Darryl Futrell Collection Of Tektites
Now owned by The Meteorite Exchange, Inc. (more detailed images below)
The North American Strewn Field contains the Texas Bediasites, Georgia tektites, a single specimen from Martha's Vineyard (an island off Massachusetts), and a single specimen found in Cuba. Tektite fragments have been found off-shore New Jersey, and microtektites are found from the oceans off New Jersey, The Gulf of Mexico, and the Caribbean. The age of this strewn field is approximately 35.5 million years old.
Bediasites are mostly dark brownish green to black in color while a small number at the western end of the strewn field near Moldoon are a lighter green. Bediasite comes from the Bedol Indians and town of Bedias. Virgil Barnes was one of the first scientists to study Bediasites in depth. The first identified Bediasite was brought to the University Of Austin, Texas in 1936. It was identified by H. B. Stenzel. The specimen was brought in by George D. Ramsey.
Bediasites are found in 9 Texas Counties covering 7373 square miles. The largest specimen is 193 grams. It has been reported that less than 1 percent of specimens show their original etching and most have been tumbled and eroded by running water or experienced corrosion by acid waters. The specimen shown on the left is an example of a Bediasite Teardrop. Very few Bediasites show the classic splash form shapes, Teardrops, Dumbbells, Bars. Most are spheres, half spheres and irregular in shape.
There exist a couple of very rare specimens showing aerodynamic sculpting. These specimens are cores similar to Australite cores. These cores exhibit crescent and circular surface features also known as "worm tracks".
The Source Crater
In 1987 a deep sea drilling core, DSDP 612 drilled off the New jersey coast was the first drill core to yield tektite fragments, microtektites, shocked minerals coesite and stishovite. Finding tektite fragments with microtektites and other impact indicators together was a breakthrough for tektite research and the terrestrial impact theory.
In 1992 seismic reflection profiles indicated a possible impact crater named Tom's Canyon Crater but although it's ejecta blanket contains tektite fragments, it's 24 x 13.5 km size is too small to be the source crater.
In 1994 Dr. Pong published his finding of the Chesapeake Bay Crater beneath Cape Charles. Seismic reflection anomalies show a crater hidden below a few hundred meters of sediments. The impact crater is 90 km in diameter, almost 2 km deep, and resembles the Nordlinger Ries crater with a central ring. The impact generated a series of enormous tsunamis.
Please click on the USGS links below for full size images
that are readable.
Courtesy of USGS http://pubs.usgs.gov/prof/p1612/fig1.html
Courtesy of USGS http://pubs.usgs.gov/prof/p1612/fig2.html
Courtesy of USGS http://pubs.usgs.gov/prof/p1612/fig2.html (scroll down page)
For more USGS information please see http://pubs.usgs.gov/prof/p1612/powars.html#CHES