Tuesday, February 21, 2017

Round Rocks of Missouri

This adventure started more than 300 million years ago. I wasn't around then which is a good thing. Because something pretty drastic happened. It was in 1948 that a geologist first noticed that the area around Weaubleau Creek was different. That something pretty unusual had happened there many, many years ago. It wasn't until 2003 or so that a geologist began digging a little further and has put together evidence that a large meteorite, 1200 feet long impacted in the area just south of what is now Osceola, MO around 310 to 340 million years ago.

Back then Missouri was covered in a shallow sea. When the meteorite struck it created a crater that was 12 miles wide and jettisoned rocks and debris over a much larger area. Geologist combing the area have found evidence of this impact and are continuing to put together the pieces to make their case. The impact site is located north of Coon Creek and just south of the Village of Vista, Missouri to the west of Highway 13.

Close up of Missouri rock ball from roadside park.
But if you go there you won't see anything you'd recognize as a crater. What you can find in the area, particularly to the north and east of the site are what have been called by locals for years "round rocks" or "Missouri rock balls." These round rocks range from golfball size to grapefruit size with some reports of rocks as large as basketballs. Resident of the area find this rocks laying on the surface of the ground or washed out of river banks or road cuts. I found several round rocks in a road cut along Highway 13 and one along a low water bridge in the impact area.

At a roadside park on Highway 8 south of Osceola, MO.
Residents of the area have know for years about the round rocks. They have used them in building projects for many years.

It seems that when the meteorite struck it broke up gravel sized bits of shale that in the soup of silt and minerals that remained after the impact eventually conglomerated to make these round rocks.

There are many geologic wonders of Missouri left to be rediscovered by you. Get out and see what you can see of this wild Missouri.

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