CraigHyatt Posted May 22, 2016 Share Posted May 22, 2016 A beautiful split concretion embedded in a block of hard sandstone. Probably not a tree, but seems to have growth rings and outer bark. Info: Craig Hyatt, retired software/electrical engineer Experience: Beginner, fossil hunting less than a year Location: Eagle Pass, TX USA on the border with Mexico, hot dry desert Formation: Escondido, Marine, Upper Cretaceous Materials: Sandstone, Mudstone, Shale, Chert, Chalk Typical: Thalassinoides, Sphenodiscus, Exogyra, Inoceramus Reference: http://txfossils.com/Txfossils.html Link to comment Share on other sites More sharing options...
tmaier Posted May 22, 2016 Share Posted May 22, 2016 My guess would be that at the center was (is) an iron-bearing material, and successive saturations with water and drying caused the iron to leach out in these rings each time. Are you familiar with TLC (Thin Layer Chromatography)? The rings have that characteristic, of having the water transport the material through the medium, and creating a gradient of material deposited each time. I wonder what the object in the center is? Link to comment Share on other sites More sharing options...
CraigHyatt Posted May 22, 2016 Author Share Posted May 22, 2016 Don't know TLC. Sounds something like electrophoresis? Edit: I mean the diffusion part, not they are literally the same. Info: Craig Hyatt, retired software/electrical engineer Experience: Beginner, fossil hunting less than a year Location: Eagle Pass, TX USA on the border with Mexico, hot dry desert Formation: Escondido, Marine, Upper Cretaceous Materials: Sandstone, Mudstone, Shale, Chert, Chalk Typical: Thalassinoides, Sphenodiscus, Exogyra, Inoceramus Reference: http://txfossils.com/Txfossils.html Link to comment Share on other sites More sharing options...
CraigHyatt Posted May 22, 2016 Author Share Posted May 22, 2016 ...thing in the middle... Left as an exercise for the interested student. This student ain't interested in carrying a 200 lb rock. That's too much exercise. Info: Craig Hyatt, retired software/electrical engineer Experience: Beginner, fossil hunting less than a year Location: Eagle Pass, TX USA on the border with Mexico, hot dry desert Formation: Escondido, Marine, Upper Cretaceous Materials: Sandstone, Mudstone, Shale, Chert, Chalk Typical: Thalassinoides, Sphenodiscus, Exogyra, Inoceramus Reference: http://txfossils.com/Txfossils.html Link to comment Share on other sites More sharing options...
tmaier Posted May 22, 2016 Share Posted May 22, 2016 Yeah, similar to electrophoresis separation. Only you don't need the power supply. Link to comment Share on other sites More sharing options...
CraigHyatt Posted May 22, 2016 Author Share Posted May 22, 2016 My guess would be that at the center was (is) an iron-bearing material, and successive saturations with water and drying caused the iron to leach out in these rings each time. Are you familiar with TLC (Thin Layer Chromatography)? The rings have that characteristic, of having the water transport the material through the medium, and creating a gradient of material deposited each time. I wonder what the object in the center is? I was secretly hoping it was a tree.... I might have a chance to find something besides ammonites and oysters. ;-)Also notice how the core shape rotated with successive saturations. That means there's a porosity gradient in the surrounding stone. Of course it wouldn't be perfectly uniform. Thanks so much for all your great explanations. Learning a lot here. Info: Craig Hyatt, retired software/electrical engineer Experience: Beginner, fossil hunting less than a year Location: Eagle Pass, TX USA on the border with Mexico, hot dry desert Formation: Escondido, Marine, Upper Cretaceous Materials: Sandstone, Mudstone, Shale, Chert, Chalk Typical: Thalassinoides, Sphenodiscus, Exogyra, Inoceramus Reference: http://txfossils.com/Txfossils.html Link to comment Share on other sites More sharing options...
tmaier Posted May 22, 2016 Share Posted May 22, 2016 Isn't the formation you are picking through a marine environment? You should count yourself lucky to be finding what you have. There are fossil starving people in some locations, you know. Link to comment Share on other sites More sharing options...
CraigHyatt Posted May 22, 2016 Author Share Posted May 22, 2016 Isn't the formation you are picking through a marine environment? You should count yourself lucky to be finding what you have. There are fossil starving people in some locations, you know. Ha ha ha. Yeah, I should count my blessings. :-D This area was marine, but finding a tree would mean a layer where the water had receded. https://en.m.wikipedia.org/wiki/Western_Interior_Seaway Info: Craig Hyatt, retired software/electrical engineer Experience: Beginner, fossil hunting less than a year Location: Eagle Pass, TX USA on the border with Mexico, hot dry desert Formation: Escondido, Marine, Upper Cretaceous Materials: Sandstone, Mudstone, Shale, Chert, Chalk Typical: Thalassinoides, Sphenodiscus, Exogyra, Inoceramus Reference: http://txfossils.com/Txfossils.html Link to comment Share on other sites More sharing options...
abyssunder Posted May 22, 2016 Share Posted May 22, 2016 For me the concentric rings looks to be nice Liesegang rings. https://en.wikipedia.org/wiki/Liesegang_rings_%28geology%29 " 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...
tmaier Posted May 22, 2016 Share Posted May 22, 2016 For me the concentric rings looks to be nice Liesegang rings. https://en.wikipedia.org/wiki/Liesegang_rings_%28geology%29 Yeah, that looks right. The wikipedia article mentions that this mechanism still isn't understood. Link to comment Share on other sites More sharing options...
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