Tethys Posted March 19, 2015 Share Posted March 19, 2015 Another piece from Burleigh county. There is a large hill of ice thrust Fox Hills formation at this site, parked on top of Cannonball formation and Bullion Creek and covered with glacial debris. Fox Hills is a near shore marine formation. The others are terrestrial. The surface texture looks like some of the bones I have seen here, but the inside of the rock seems wrong for bone. It is 31 mm long. 20 mm high, and 22 mm wide. Photos are top, bottom, and side view respectively. Link to comment Share on other sites More sharing options...
Tethys Posted March 19, 2015 Author Share Posted March 19, 2015 Two more photos. A close up of the top, and a view of the broken side. Link to comment Share on other sites More sharing options...
Auspex Posted March 19, 2015 Share Posted March 19, 2015 I am pretty sure this is a siderite nodule. "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Tethys Posted March 19, 2015 Author Share Posted March 19, 2015 I did a scratch test. The brown inner portion left a rust colored streak, and the black part makes a brown streak. I think that is consistent with siderite? Any ideas on what created the surface texture? Link to comment Share on other sites More sharing options...
Philosoraptor Posted March 19, 2015 Share Posted March 19, 2015 Yep. Your right that it is consistent with siderite. Not so sure on what caused the surface texture. Maybe just caused by being shifted back in forth through the rest of the debris. Not certain though. Link to comment Share on other sites More sharing options...
jpc Posted March 19, 2015 Share Posted March 19, 2015 I have heard that that sort of texture is caused by microbes eating the rock in weird patterns. That's what they say about that texture in rocks form the Sahara, anyway. Yeah, siderite nodule. The Cannonball is marine, isn't it? Link to comment Share on other sites More sharing options...
Tethys Posted March 19, 2015 Author Share Posted March 19, 2015 jpc ~ The Cannonball is marine, isn't it? It is marine in the Williston area, but is characterized as brackish swamp or mudflats in other areas according the the NDGS. The preglacial beds of the heart and cannonball rivers are both in this area, so I was just trying to be thorough with the possible sources for this rock. Link to comment Share on other sites More sharing options...
Auspex Posted March 19, 2015 Share Posted March 19, 2015 I have heard that that sort of texture is caused by microbes eating the rock in weird patterns. That's what they say about that texture in rocks form the Sahara, anyway. Yeah, siderite nodule. The Cannonball is marine, isn't it? In this case, microbes are involved with the creation of this rugose pattern, but in its deposition: they 'eat' trace organics, and their excretions fix the iron oxide. "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Tethys Posted March 20, 2015 Author Share Posted March 20, 2015 Thanks for your opinions. The whole concept of iron oxide precipitated by decomposing microbes is fascinating. The patterns are so regular I thought it might have a biological origin. I pulled out the petrified wood collection and it ranges from modern looking spruce to lignite to something that seems more like a palm. I'm guessing it is all different ages. I still haven't managed to check off toredo bored wood from the bucket list. Link to comment Share on other sites More sharing options...
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