The Geological Formation of the
Straight Branch Waterfall
Typically, a river or in this case the Straight Branch, flows
over a large step in the rocks which may have been formed by a
fault line. Over a period of years, the edges of this shelf will
gradually break away and the waterfall will steadily retreat
upstream, creating a gorge of recession. Often, the rock stratum
just below the more resistant shelf will be of a softer type,
meaning undercutting, due to splashback, will occur here to form a
shallow cave-like formation known as a rock shelter or plunge pool
under and behind the waterfall. Eventually, the outcropping, more
resistant cap rock will collapse under pressure to add blocks of
rock to the base of the waterfall. These blocks of rock are then
broken down into smaller boulders by attrition as they collide with
each other, and they also erode the base of the waterfall by
abrasion, creating a deep plunge pool.
The Straight Branch Creek becomes wider and more shallow just
above waterfalls due to flowing over the rock shelf, and there is a
deep pool just below the waterfall because of the kinetic energy of
the water hitting the bottom.
At the waterfall, you will see what the Straight Branch has done
which results in all of this beauty. Remember, it took thousands of
years for it to happen.
Over several thousands of years, Mother Nature used the Straight
Branch to carve out the Falls that you will enjoy.
.
The bedrock of these falls is primarily sandstone.
Waterfall
Classification
Block: Water descends from a relatively wide stream
or river. Water descends a series of rock steps.
Cataract: A large waterfall.
Fan: Water spreads horizontally as it descends while
remaining in contact with bedrock.
Horsetail: Descending water maintains some contact with
bedrock.
Plunge: Water descends vertically, losing contact with the
bedrock surface.
Punchbowl: Water descends in a constricted form, then
spreads out in a wider pool.
Segmented: Distinctly separate flows of water form as it
descends.
Tiered: Water drops in a series of distinct steps or
falls.
Multi-Step: A series of waterfalls one after another of
roughly the same size each with its own sunken plunge
pool.
Which One AM I?
Note:In order to receive credit for this Earthcache
you must do the following:
1. Upload a photo of your GPSr pointing to the base of the
falls. While it would be nice, you do not have to have to show your
face(s) in the photo.
2. Send an email with answers to the following
questions; A. Estimate to within 10 +/- feet the height and
width of the falls,
B. From the above (or other information), what is the
classification of this falls?
Feel free to post additional photos of the falls. Take care
and have a good caching day.
This Earthcache was approved by the
Geological Society of America
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