A waterfall is an indication that a stream is geologically young and active. The water flows over a resistant bedrock slower upstream and faster downstream causing erosion to occur more quickly downstream. This difference in velocity is caused by the increasing volume as the stream picks up more run off water and the from effects of gravity.
Pounding water and whirlpools increase the rate of erosion even faster at the base of a fall causing the waterfall to increase in size. This erosive action also causes the waterfall to move further up stream at a geologically slow rate. Often the receding erosion created by the waterfall will create a canyon downstream and a rock shelter in the soft rock behind the veil of the falls.
Here at Frankfort Mineral Springs evidence of that geological process is evident. The quarter mile canyon leading to the veiled water fall is sheer and steep. At the current location of the falls rock shelters occur in the canyon walls on both sides. Eventually the the rock outcropping created by the falls will collapse and send larger stones to the base of the falls for further erosion and tumbling downstream. There is evidence of a recent collapse to the right of the Frankfort Mineral Spring fall. It is only a matter of time that the rock shelters created by the falls will succumb to the process of erosion and continue the geologic cycle openly on display.
This collection of images and video record my observations at the water fall’s most geologically active point and the patterns created as the ongoing erosion cycles. I watched the force exerted by the cascading water and can only imagine that sometime in the near future this process will have an observable effect at Frankfort Mineral Springs.
On a cold winter’s Saturday at Gull Point located at the lonely tip of Presque Isle, Pennsylvania, snow falls over the land spit. The view due north over the vast and motionless horizon of water and sky is an unseen Canada. Where water meets shore the sound of eighteen inch waves crashing in an undulating and cyclical pattern. The ebb and flow permeates a relaxing orchestra over the grey winter’s landscape. Lake Erie is a fresh water lake and, like the larger oceans, experiences the phenomenon of the tides, or does it?
The tides are the combined force of the gravitational pull from both the sun and the moon. The breadth and frequency of the tides are based upon the position of the sun and moon in relationship to one and other, the rotation of the earth and the bathymetry, or contours of the land located under very large bodies of water. Other factors that affect the size of the tides are barometric pressure and storm surges.
The scale of Lake Erie along with the other Great Lakes is exponentially smaller than the world’s oceans. At a similarly small exponential rate the Great Lakes do feel the gravitational effects of the tides. In reality the lunar and solar tides affecting Lake Erie amounts only to a few inches. Generally, the waves on Lake Erie are created by wind and weather as it moves from west to east and not by the effects of the sun or moon. As the waves move from open water towards the shore, the inclination of lake floor causes the waves to break as they approach the land creating the crash that fills the air with sound and slowly erodes and transforms Presque Isle.
This collection of images and video record my observations at the wave’s point break and the patterns created as they cycle up and down the sandy coast of Pennsylvania’s lake shore. I noticed as the waves moved in and out another pattern of residual moisture ebbed at a much slower rate and allowed for a beautiful interaction of light where the water from Lake Erie meets the land of Pennsylvania.