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Virginia Department of Historic Resources

Morrow Mountain Rhyolite-Uwharrie Mountains



Morrow Mountain Rhyolite, Uwharrie Mountain, 31ST0018, North Carolina.

Type Rhyolite

Collection Location:
This sample of Uwharrie rhyolite came from Morrow Mountain, site 31ST18.

Description
Morrow Mountain Rhyolite, a metarhyolite, is used to refer to a series of mixed lava flows producing a sheet-like deposit. The rapid cooling of the lava and the low-grade metamporphism of the region produced the good-to-excellent conchoidal fracture of the stone. This type is a homogeneous dark gray, aphanitic, aphyric rhyolite that commonly exhibits flow banding, especially on slightly weathered surfaces. However, on recently flaked rhyolite, the flow lines are difficult to see. When present, flow lines are thin, only a few millimeters. Extremely old and weathered debris exhibit a chalky grayish-white exterior. Some specimens exhibit small spherulites, ca. 1 mm in diameter, which appear as tiny patches of radiating fibers (Daniel & Butler 1996).

Distribution
Daniel reported that Uwharrie rhyolite is distributed widely across the piedmont of North Carolina and down into South Carolina.

Cultural Implications
Uwharrie rhyolite was used from Early Archaic through the Late Woodland periods

References

Prepared By Egloff 2008