Students from Dr. Keith Milam’s Planetary Geology class visited the Flynn Creek impact structure to examine the mostly buried, but partially exhumed, 3.8 km diameter crater in north central Tennessee.
The students spent much of their time above ground, where they stopped at several locations along the crater rim and were afforded the rare opportunity of standing on the crater floor. When surface exposures were lacking or limited, the students traveled underground in some of the many caves that formed in the crater rim and central uplift long after the impact that occurred 382 million years ago.
In fact, the unique geologic setting of Late Devonian-Early Mississippian Chattanooga Shale overlying deformed Ordovician-aged target rocks has resulted in one of the highest concentrations of caves and karst features in north central Tennessee.
One such cave, Geological Sciences student Emily Simpson’s “favorite stop on the trip,” was Hawkins Impact Cave. It’s the only known cave within the central peak of a complex crater anywhere on Earth. Students had a chance to crawl through this unique cave formed between giant blocks of limestone that had risen several hundred feet immediately following the impact event.
Emerging from the depths of the Earth well after sunset, the wet and muddy students were exhausted but, according to Geological Sciences senior Elizabeth Sampson, had a “great trip!”
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