tag:blogger.com,1999:blog-8693614218792476252.post2296984079085722441..comments2024-03-09T08:06:26.066-08:00Comments on Looking For Detachment: Friday Field Photos: Mystery CracksSilver Foxhttp://www.blogger.com/profile/03131032620978696727noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-8693614218792476252.post-13578657923344701542010-09-25T17:32:17.992-07:002010-09-25T17:32:17.992-07:00I've seen similar patterns on a much smaller s...I've seen similar patterns on a much smaller scale in rhyolite and ash-flow tuffs that have flowed into water, and that was the first thing I thought of. I didn't think these were really pillows, but am intrigued by the degassing from below idea. Most geos on twitter think it's spheroidal weathering not related to the flow's cooling properties.<br /><br />I remain unsure. (It would be time for more study if I lived up there.)Silver Foxhttps://www.blogger.com/profile/03131032620978696727noreply@blogger.comtag:blogger.com,1999:blog-8693614218792476252.post-47193955098768092692010-09-25T10:17:10.702-07:002010-09-25T10:17:10.702-07:00They look like a combination of pillow basalt and ...They look like a combination of pillow basalt and degassing of the underlying water bearing sediments. Might be a flow into a fresh water lake or stream that drove all the water out and then cooled into columns. There is defintely some sort of preferential weathering taking place. Good eye spotting this. I will have to keep an eye out for this sort of thing while travelling through eastern Washington.Dan McShanehttps://www.blogger.com/profile/17044037213245602667noreply@blogger.com