Today we ran only the Chirp. We went back north to where we found the Upper Claiborne
riddled with faults and ran an additional 7 surveys of the area. It is likely that
Xenia will map the system in 3D to determine the strike and dip of the faulting. This
information will help us ascertain the stress field needed to create these tectonic
We also ran the Chirp at the plunge pool. The plunge pool is located just south of
Hickman, KY. The Mississippi River flows gently to the south at a depth of ~50 ft,
then suddenly spins, churns, and visibly flows backwards! In one area a whirlpool
caused a slight depression in the water surface. Now a canoe would have an extremely
hard time in this area. Barge traffic navigating the river try to avoid the area.
So what’s going on? The river rides over something not erodible…or at least difficult
to erode. This bump in the river bottom causes the river to erode down on the downstream
side of what we think is clay. And it scours! The river scours an additional 100 ft
into the riverbed, eating out a hole about a football field wide, 3 football fields
long and 150 ft deep. That’s the plunge pool. We ran 5 surveys across the plunge pool
with the Chirp. The data was hard to interpret and will take a keen eye to figure
out what’s going on.
It was a long day, but quite productive and fruitful.