There is absolutely no bushwhacking necessary to find this
location. The walk from the parking location to the feature is less
than 0.10 miles, please take the path.
Please park on the grassy shoulder so that traffic can get by. The
coordinates for the cache are for the park entrance off of
Pulleytown Road. There is also parking off of Route 96, but if
there is water, you may get wet or worse trying to get to the
feature, rocks are moss covered and can be slippery.
Please note: This one is a virtual cache since the location you
are finding is within a NC State Park and even thought this is an
undeveloped/unmanned park I’ll respect the NC State Parks policy on
no real-geocaches.
Also, it is NC State Park policy that you can not collect samples
from or within the park boundaries.
To confirm this find you need to take a compass reading for the
feature at the following coordinates N 35 55.085 W 078
23.392
Here is some info on the feature you are looking for.
The Setting: When you enter this park, you are approaching
one of the largest naturally exposed outcrops of granite in NC.
Such a large outcropping in a horizontal orientation is called a
pavement, but please don’t try to drive on to it!
This is part of the Rolesville batholith - a batholith is a
large mass of magma that cooled below the earth’s surface. Because
layers of rock and earth above it insulated the magma, the mineral
crystals are larger than if this had been a volcano and the magma
had cooled on the earth’s surface.
Some of the rock that you are standing on cooled over 298
million years ago, during the Paleozoic Era. These rocks represent
one of the youngest stages in the formation of the Alleghenian
Mountain building event, which was a stage in the formation of the
Appalachians mountains. The Rolesville batholith is the largest of
these magma masses (otherwise called a pluton) in the southern
Appalachians.
You are seeing only a fraction of it, N to S it runs from north
of Henderson to south of Clayton - and that’s just where it is the
surface bedrock!
The Feature: As the magma cooled, fractures formed,
through which more magma rose through and then crystallized. Due to
the chemical and physical nature of the rock (in this case granite)
these fractures have specific characteristic orientation. The set
of coordinates given in the description above is for a very large
fracture which when you are standing on it you can see that it runs
both behind and in front of you - take your reading looking in
either direction.
Extra credit: If you find another fracture that
intersects the feature or another set of intersecting fractures you
could then measure the angle that is characteristic of fracturing
in granite, and earn 10 extra credit points for Geology I. (Don’t
happen to have protractor with you – take the compass reading for
each and subtract and this will give you one of the two angles
formed. The other angle is your first value subtracted from
180).
To log this find: Email cache owner the compass reading
and extra credit info for confirmation, do not include it in your
log, not even encrypted. When you see the feature, you will
understand what I mean by taking a compass reading.
By the way, the majority of the outcrop is a Monzonite, medium
grained rock, with feldspar (White, matted mineral) predominant,
some hornblende (Black mineral) and quartz (Gray, glassy mineral).
By comparing the crystal size in the feature with the surrounding
rock, you can see what a good insulator granite can be – the bigger
the crystals, the slowed the cooling. Granite with such large
crystals is called a Pegmatite.
Note: Geologic information compiled from Field Trip Guidebook,
50th Annual Meeting Southeastern Section Geological Society of
America, Raleigh, NC, April, 2001