Mole Hill: Traversing an Ancient Volcano

Mole Hill is a conical hill, the eroded remains of a 50-million-year-old volcano with a plug of olivine basalt as its core, located southwest of Harrisonburg (38.448788, -78.953639) near Dale Enterprise.

[approaching Mole Hill, facing WNW]

One of Virginia’s two known volcanic plugs (a conduit or pipe which fed molten igneous rock to a volcano), this early Paleozoic carbonate bank is intruded by other volcanic rocks in the form of sills and dikes, but do not stand out topographically.  The last volcanic activity in this region was during the Eocene Epoch (50 million years ago). 

The ride to the highest point by road is Route 913 (Mole Hill Road) a 1260 ft climb from the bottom of the road at 1 mile (SE to NW). 

[Leaving Mole Hill facing ESE]



Resources:

Keith Frye, Roadside Geology of Virginia (Missoula, MT: Mountain Press Publ. Co. 1986).

Volcanoes in Virginia 

What Lies Beneath the Valley's Crust? Local Landmark May HaveAnswers

A Brief Geological History of Rockingham County

Local news story, WHSV, 5/24/2017