Virginia State Geologist Visits Naked Mountain

On Friday, March 30th, I had a special experience when David Spears, Virginia State Geologist, came to see Naked Mountain. He brought his son, Evan Spears, a ranger and naturalist with the State Parks Division of the Virginia Department of Conservation and Recreation, and Ty Smith, intern and naturalist with State Parks.

While we walked to the summit, and into the barrens, Evan and Ty were constantly calling out the names of birds they heard and saw. Most were resident woodpeckers, but they pointed out a few migrants – Blue-headed Vireo and Hermit Thrush. They also spotted a Bald-faced Hornet which politely posed for photos.

David made an interesting observation about how the vegetation in the Naked Mountain Natural Area Preserve changes dramatically as you come up the long, 2.5 mile road. At the beginning of the preserve boundary, and for about a half mile, the vegetation denotes an acidic soil base – lots of Mountain Laurel, and a sparse understory. But as you turn a corner to begin the long two mile journey up to the ridge top, the vegetation is indicative of strongly alkaline soils – Mountain Laurel abruptly disappears, and species like Red Bud and White Ash trees and plethora of understory are evident.

At the house, before we left for the trek into the barrens, I showed David the vegetation map and report of the preserve on this website which Natural Heritage staff, Kristin Taverna and Gary Fleming, produced. It shows the portion of the Virginia geologic map that underlies the preserve. You can clearly see that granite, a rock that produces acidic soils, is under the Eastern most section of the Naked Mountain preserve, while amphibolite, a mafic rock that produces alkaline soils, underlies the remainder. Natural Heritage has done soil analysis in several vegetation plots and reports that the soils in the Naked Mountain Natural Area Preserve contain calcium levels at the highest end of the range for Virginia.

In the barrens, David pointed out fractures in the seeping amphibolite rock and explained water is generally held in such fractures throughout the rock substrate. He also pointed out boulder streams, sizable rocks that move like extremely slow lava streams down the mountainside. He noted the evidence of this in the J-shaped trees on the steep slope. He pointed out the difference between the boulder streams and the bedrock that is exposed in the heart of the barrens. This rock breaks off over time, but doesn’t move.

Then, Evan discovered a strange bright blue stripe in an otherwise black rock. David explained it was a striking seam of blue quartz and said he had never seen such a strong example of this in amphibolite. He said if you took a brush and scrubbed the surface, the whole seam would be bright blue. Amazing!

My visitors were all astonished at the numbers of emerging Shooting Stars – estimated by Natural Heritage staff to be at least 10,000 and the blooming spring ephemerals on the summit and in the barrens.  Here are some photos of those beauties.