Sunday, August 14, 2011

The Johnson Shut-Ins

Here are some pictures from our fun day at the Johnson Shut-ins. What are the Johnson Shut-Ins you ask. Here is the info:
Nearly 1.5 billion years ago
, violently explosive volcanoes hurled hot gasses and ash into the air. The ashes and gas fell and cooled, forming rhyolite rock. A billion years later, shallow inland seas swallowed the ancient, worn-down mountains, burying the igneous rock under thousands of feet of sedimentary rock such as limestone, sandstone, shale and dolomite.

About 250 million years later, the entire Ozark region lifted and the seas retreated. The wind and rain took their toll on the upraised land, sending streams of sand- and gravel-laden water to slice away the layers of soft sedimentary rock and expose the rhyolite below. In low places, the swift Black River became shut-in by the hard igneous rocks, swirling and churning to form huge potholes, and breaking away the weaker rock to create natural water slides and canyon-like gorges

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