Virginia State Geologist Visits Naked Mountain

 

Right to Left: David Spears, Virginia State Geologist; blog and memoir author, Marcia Mabee; Evan Spears, State Parks Ranger and Naturalist; Ty Smith, State Parks Intern and Naturalist.

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.

Bald-faced Hornet next to nest hole on decaying log. Naked Mountain Natural Area Preserve, Virginia.

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.

Virginia State Geologist, David Spears, in the barrens in the Naked Mountain Natural Area Preserve. Note dozens of emerging Shooting Stars, among an estimated 10,000 that bloom nearly simultaneously in the preserve.

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!

A seam of blue quartz embedded in the amphibolite rock that is characteristic of the Naked Mountain Natural Area Preserve.

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.

Bloodroot blooming on the summit of the Naked Mountain Natural Area Preserve.

Spring Beauty blooming on the summit of Naked Mountain.

Cutleaf Toothwort blooming on Naked Mountain. This is an extremely prolific spring ephemeral all over the preserve turning some portions of the otherwise brown leaf duff green and white.

 

 

Vegetation Map of Naked Mountain is here!

Early last year, I received a very exciting phone call from Gary Fleming, the Senior Vegetation Ecologist with the Natural Heritage Division of the Virginia Department of Conservation and Recreation. He was calling to let me know that Naked Mountain would be the first Natural Area Preserve to undergo a complete vegetative mapping of its natural communities. Mapping has been done in national parks in Virginia, but never before in one of the state’s own dedicated natural area preserves. I was thrilled that Naked Mountain would be the first, and pleased to know more NAP’s are undergoing mapping.
The principal ecologist on the Naked Mountain project was Kristen Taverna, joined for a couple of visits by Gary Fleming. Kristen collected 59 observation points across most of the 278 acres of the preserve including points at 1080 feet and at the 2000 foot summit. Her work supplemented five vegetation plots that Gary established during visits between 2007 and 2012 within which every plant species is identified. Kristen’s observations are more generally descriptive of the plants that make up a particular natural community type.

From Left:  Kristin Taverna, Gary Fleming, Karen Patterson taking a photo of Spring Forget-me-not, Myosotis verna

From Left: Kristin Taverna, Gary Fleming, Karen Patterson taking a photo of Spring Forget-me-not, Myosotis verna


In all, Kristen and Gary identified five natural heritage resources, also known as element occurrences, on Naked Mountain including three significant natural communities and a small population of the globally rare plant, Torrey’s mountain-mint (Pycnanthemum torreyi). You can see a photo of the mountain-mint on the blogsite header. It is the pale purple speckled plant to the far right in the third slide of the changing header.
The two most important natural communities on Naked Mountain are: Central Appalachian Basic Ash-Hickory Woodland and Central Appalachian Mafic/Calcareous Barren (Low-Elevation Type). These are globally rare. But the most exciting floral display on Naked Mountain are the Shooting Stars (Dodecatheon primula). Botanical experts estimate that as many as 10,000, if not more, bloom across the warren of small openings across the Southeastern face of the mountain. And they bloom all at once in early May. I discovered this magnificent nature show myself ten years ago, and as the mapping report notes, it was the catalyst for the decision to complete a conservation easement with the Virginia Department of Conservation and Recreation. This story is captured in my memoir which will be published in September. You can get a glimpse of the Shooting Star display on the second slide of the changing blogsite header.
A part of the report that I find very interesting is the soil analysis. I learned from David Spears, Virginia’s state geologist, that the underlying bedrock of Naked Mountain is amphibolite, a metamorphosed rock. He explained that a, not quite continuous, narrow extrusion of the rock extends from Naked Mountain for about forty miles to the Northeast, running under the great lawn at the University of Virginia, that they have dubbed, “the Great Amphibolite Dike.” Looking at the map segment below supplied by the Virginia Department of Mines and Minerals, the dark green line of the amphibolite begins just a little bit west of Elma and also forms the largest “blob” there. That blob is Naked Mountain.

Amphibolite pic
A few years ago I sent samples of Naked Mountain amphibolite to my brother Steve Mabee, who is the state geologist in Massachusetts. His analysis determined that the rock was metamorphosed from basalt, so volcanic in origins. Not surprisingly, then, the soils of Naked Mountain resemble those underlain by other mafic rock substances. Naked Mountain soils are very high in calcium and magnesium and aluminum, in fact as the report notes,” … at the upper end of the range variation for soils weathered from mafic rocks in Virginia, and indicate very high fertility.” This likely accounts for the significant biodiversity on Naked Mountain and the extraordinary display of Shooting Stars.
I hope you enjoy the report and you can go back to the menu bar and check out the plant list too!