Name/Title
S04.03.010Description
A specimen that shows spheralite filling fractures and replacing the dolomite. Bleaching of the dolomite, where replacement occurred is not common but occasionally it is found near the dark Blackjack sphalerite as in this sample, which has been wetted for the photograph. The specimen shows contemporaneous solution of the dolomite and deposition of sphalerite. The photograph was taken by Stephen P. Reidel for his Geology of the Serpent Mound Cryptoexplosion Structure a thesis submitted in partial fulfillment of the degree of Master of Science to the University of Cincinnati in 1972. It appears as Photo 39 in his thesis document. The specimen was collected from the north border of the peripheral area of the Serpent Mound Impact Structure at Location 24 given in Reidel's thesis.
The Serpent Mound Impact Structure is an approximately 9-mile-diameter area of highly disturbed and structurally deformed bedrock at the intersection of Adams, Highland and Pike counties. The area of the impact structure has dolomite, shale, limestone, sandstone, and siltstone lithologies. Because of the geologic forces that have acted on the site of the impact crater, bedrock in the area is a mixture of uplifted, down dropped, faulted, folded and eroded rock from the Ordovician, Silurian, Devonian and Mississippian Geologic Periods. The deeply eroded crater is believed to have been formed by an asteroid or a comet impact approximately 250 to 300 million years ago. It is named the Serpent Mound Impact Structure after the prehistoric American Indian effigy earthwork located near the southwestern edge of the area. It is the single-most complex geologic structure exposed at the surface in Ohio. Investigation of the impact structure has been done using rock cores, seismic data, geophysical surveys and remote satellite imagery for the area.
This slide image included in the USGS National Digital Catalog for NGGDPP Grant G15AP00115 in FY2015.Context
Dolomite rock sample with fractures and holes in it; a second rock has filled a few of the holes. From Serpent Mound Impact Structure in Adams County, Ohio.