older the better Posted December 14, 2017 Share Posted December 14, 2017 I found this on a gravel bar in se Kansas the surface rocks are Pennsylvanian age. it looks to me like fossilized mud cracks, first I would like to know if you guys agree. second I'm trying to figure out how this was formed, the cracks curve around the edge of the rock and show up on the bottom edge. my guess is that it was pressed up on the one side exposing it to the air, maybe from something stepping in the mud? anybody have a better explanation? Link to comment Share on other sites More sharing options...
older the better Posted December 14, 2017 Author Share Posted December 14, 2017 sorry for the odd way of doing this but I don't know how to resize images Link to comment Share on other sites More sharing options...
Rockwood Posted December 14, 2017 Share Posted December 14, 2017 It could well have been mud at one time, but the cracking may be caused by the weathering process. Hydration and oxidation of minerals result in expansion which drives the process. Link to comment Share on other sites More sharing options...
abyssunder Posted December 15, 2017 Share Posted December 15, 2017 I think, this link might help to elucidate the mysteries of evolution and patterns of cracks. " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
older the better Posted December 15, 2017 Author Share Posted December 15, 2017 I don't think this is a weathering pattern the cracks are semi octagonal and are consistent with the rest of the stone, not weathered or crumbly. what has me hung up is the cracks aren't just on the top surface they wrap around the side and even appear below. I know mud can pull up in large plates when really dry but this seems too thick and rounded. I looks to me like if someone stepped on a ball of play-doh. that's the part that has me hung up and interested how did it get that way is it possibly a partial animal track? the small pits and pebble inclusions are a bit odd too. I'm guessing maybe the pits all had pebbles in them and some fell out and the river smoothed out the holes Link to comment Share on other sites More sharing options...
Missourian Posted December 15, 2017 Share Posted December 15, 2017 The rock looks like a concretion. The cracks may have occurred during its formation, similar to those of a septarian concretion, more or less. Context is critical. Link to comment Share on other sites More sharing options...
westcoast Posted December 15, 2017 Share Posted December 15, 2017 +1. Looks like an ironstone-type concretion. Link to comment Share on other sites More sharing options...
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