Brook Run jasper, 44CU0122, Culpeper County, Virginia.
The jasper sample is from site, 44CU0122, a seam of jasper mined as a quarry 10,000 years ago, located in western Culpepper County, east of Brook Run, Virginia.
Brook Run jaspers were formed under hydrothermal conditions, mediated by microbes. Fossilization of these microbial filaments has resulted in a distinct petrographic character. The wall surrounding the jasper seam is composed of red sandstone and siltstone. The jasper occurs as brecciated masses that are cemented together with black chert. The angular pieces of jasper can be quite large and have white rinds and fractures that are filled with black chert.
Although the Brook Run jasper is distinctive from other sources of jasper, its cultural distribution is unknown. There are only a few known sites in the region with evidence of jasper.
The evidence suggests that bifacial quarry blanks were manufactured and removed from the Brook Run Jasper Quarry only from the late Paleoindian and Early Archaic periods. There is no evidence of heat treatment at the quarry site, and no evidence of use of the quarry by later people.
Prepared By Egloff 2008