William Posted September 12, 2013 Share Posted September 12, 2013 (edited) Was this an air pocket within softer material at one time? Found in Worthington, IN. Many more pictures at the link just above this picture. Rocks like this are so numerous where I hunt, I don't bother collecting them any longer. This just happen to be a little larger than most, really clean and round (the hole). I know...there are a lot of pictures, but I was trying to publish a decent image (or 2). https://fossils.shutterfly.com/pictures/33 Edited September 12, 2013 by William Link to comment Share on other sites More sharing options...
bdevey Posted September 12, 2013 Share Posted September 12, 2013 (edited) It is a concretion, This may help.....link Sometimes there are fossils inside, good luck. Opps, after a second look , it was a concretion that filled the void Edited September 12, 2013 by bdevey Link to comment Share on other sites More sharing options...
William Posted September 12, 2013 Author Share Posted September 12, 2013 It is a concretion, This may help.....link Sometimes there are fossils inside, good luck. Thank you. So the void was created by a concretion? There was a concretion that fell out of this hole? Link to comment Share on other sites More sharing options...
William Posted September 12, 2013 Author Share Posted September 12, 2013 Thank you. So the void was created by a concretion? There was a concretion that fell out of this hole? I think I just answered my own question... http://formontana.net/concretion2.jpg Link to comment Share on other sites More sharing options...
bdevey Posted September 12, 2013 Share Posted September 12, 2013 Thank you. So the void was created by a concretion? There was a concretion that fell out of this hole? Yep,,you got it. Link to comment Share on other sites More sharing options...
William Posted September 12, 2013 Author Share Posted September 12, 2013 Yep,,you got it. Cool. I think I have a concretion. I found a very round rock last weekend. Maybe I'll break it apart and see if there's anything inside. Link to comment Share on other sites More sharing options...
William Posted September 12, 2013 Author Share Posted September 12, 2013 Yep,,you got it. Thanks again. I've always wondered how those nice round holes formed in the rocks. Link to comment Share on other sites More sharing options...
Jed '06 Posted September 12, 2013 Share Posted September 12, 2013 Hi William check out the " Freeze /Thaw" method in the forums, for splitting nodules.Hope you find a goody inside! Link to comment Share on other sites More sharing options...
William Posted September 12, 2013 Author Share Posted September 12, 2013 Hi William check out the " Freeze /Thaw" method in the forums, for splitting nodules.Hope you find a goody inside! Thanks, Jed. Link to comment Share on other sites More sharing options...
Oxytropidoceras Posted September 20, 2013 Share Posted September 20, 2013 Depending on the rock type, the void might have contained either a concretion or a clay pebble. In case of the concretion, it might been either softer or more easily dissolved than matrix surrounding it. As a result, it was either eroded out, dissolved out, or both preferentially relative to the rock surrounding it to create the void during weathering of the rock. It is also possible that where the void now is, there originally was a clay pebble, which later became shale. Being softer than the surrounding rock, it was selectively eroded to leave only a void behind. For a Canadian example, go look at "Omarolluk" at https://en.wikipedia.org/wiki/Omarolluk and "An omar (siltstone erratic) from the northern margin of Lake Superior" at http://www.turnstone.ca/rom74om.htm . Yours, Paul H. Link to comment Share on other sites More sharing options...
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