Trail Section 8 - Falls Lake Trail Geologic Guide

 

Geologic Map Trail Section 8-10

Geologic information by Edward F. Stoddard (in Bold Text).

Mileage and Trail section descriptions from Mark Edelstein with updates from March – April 2011.

Trail Section 8:

19.8 – By a graveled pull-off, to W of NC-98 causeway, reenter woods. You are still on state gamelands.

19.9 – Reach a wide power-line cut. The trail goes straight across to reenter the woods.

20.0 – Cross a wide, open roadbed

20.1 – Cross a short footbridge, without handrails.

20.3 - Cross an older, low-lying footbridge, with a sloping handrail. Soon cross a narrow roadbed.

20.5 – Cross a footbridge by another cove.

8-A:  As you continue, you cross the head of a gully without a bridge, but with a small cliff just to your right.  You can easily imagine, that when it rains hard and water moves down this gully, erosion will cause the cliff to migrate uphill toward the trail.  This is another important aspect of stream behavior, known as headward erosion.  Eventually the trail will need to be re-routed or another footbridge built.
After seeing nothing but quartz for quite some time, you will begin to encounter blocks of soapstone.

20.8 – Reach lake views, R. These will continue for a while.

8-B:  You may notice a small chunk of granular quartz on the trail, with a one-inch wide vein of milky quartz cutting through.  Then you will run into more greenish talc schist, which seems to increase in abundance along the trail ahead.
As you reach the top of the ridge, there is a single mossy-green block of amphibolite to the right of the trail.  Amphibolite is a black rock that usually represents metamorphosed basalt; it constitutes some of the pods in the Falls Lake terrane.
Around the next bend, off the trail in the gully to the right, there is a nice ledge of feldspathic biotite gneiss with some amphibolite.  These rocks dip moderately to the west.
On toward the next cove, you may notice a few more pieces of the fine black amphibolite.

21.3 – By the end of a cove, reach a high footbridge. Around the bend, cross a second high footbridge, with many steps.

8-C:  At the first bridge, there are outstanding outcrops of banded feldspathic biotite-rich Falls Lake schist.  At the overhanging ledge just above the bridge, the layers dip 45° to the west (Figure 8-C1).  There are a few small pods of amphibolite as well (Figure 8-C2).  Under the second bridge, there is a small outcrop with black patches that are probably amphibolite pods.  Also near this bridge, there are numerous large slabs of rock that have slid downhill.  In addition to headward downcutting, another mechanism by which streams erode their valleys is by undercutting the side slopes, causing downslope movements (e.g. landslides).

If you look up to the left when you cross the second bridge, and the slope looks unnatural, there is a good reason for that – this is a dam that was built across the stream valley.

22.1 – Reach a high footbridge over a small creek.

22.2 – Cross a small inlet by the end of a cove and enter a section of state parklands.

8-D:  Just above this creek crossing, there are some nice ledges of west-dipping schist and gneiss (Figure 8-D1), including a fairly unusual rock with well-formed crystals of black hornblende and red garnet (Figure 8-D2).

22.5 – Cross a low-lying footbridge over a small creek, by the end of a cove.

22.8 – Reach a gravel road by Shinleaf Recreation Area (Walk-in campsites). Turn L and go by a vehicle gate to cross a paved road (A parking area and restrooms are R) and reenter woods. Soon pass by the old Norwood family cemetery plot, L.

8-E:  The headstones in this cemetery are made of marble that likely came from Georgia or Alabama.  However, there is a slotted flat stone on the ground that was cut from the local Falls Lake terrane soapstone.

As you continue down the trail, there is a nice slabby outcrop of gneissic feldspar-biotite-muscovite schist.  It dips west at about 20°.

23.0 – After a slight descent, cross a small footbridge.

8-F:  Another outcrop of west-dipping biotite-muscovite schist, this one has some garnets.

23.3 – Cross through a large depression.

8-G:  Along the trail and then in a root ball of a downed tree, there are pieces of a fine-grained quartz-rich rock.  This is either a metamorphosed volcanic or sedimentary rock within the Falls Lake terrane.

23.4 mi – Reach New Light Road.  Turn R to walk along the grassy shoulder.

End of Trail Section 8

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