Satellite image map with outline of ancient cryptoexplosive structure (asteroid impact site) in the vicinity of Serpent Mound, Ohio
Map showing the location of Serpent Mound within the a large circular cryptoexplosive structure geologic feature in Adams County, Ohio.

Geology of the Serpent Mound and vicinity
: Serpent Mound was constructed within an unusual geologic structure interpreted to be an ancient asteroid impact structure. The structure is interpreted to have formed in the Late Paleozoic Era because the rock contains a mix of faulted and shatter blocks of sedimentary rocks of middle to late Paleozoic age (300 million years and older). The complex geologic structure of the ancient crater contributes to the unique geography of the location that the ancestral American Indians chose to construct the Great Serpent Mound. No doubt the ancient people could see the complex geologic features exposed in the creekbeds and telimited outcrop exposures and soil characteristics in the vicinity.

Serpent Mound is located in rolling hill country east of the Allegheny Escarpment. The Allegheny Escarpment is a scenic western front of a ridge on north-south-trending hills a couple miles east of Serpent Mound. The Allegheny Escarpment is composed of flat-to gently dipping sedimentary rocks of Devonian age. Serpent mound is a complex structure broken in a series of faults that offset rocks of Ordovician to Mississippian age. Serpent Mound is located on a belt of Silurian rocks along the valley west of the Allegheny From The circular stricture about 4-5 miles in diameter is a thought to be the erosional remnant of an asteroid impact structure that formed about 300 million years ago (Mississippian Period). The original surficial crater structure has been eroded away.

Click here to see a geologic map of Ohio showing more detail of the local and regional stratigraphy (Ohio Department of Natural Resources website).
See Selected References.

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