I collected this rock in 2008 in the Scottish Highlands where the Old Red Sandstone is cut and displaced by the Highland Boundary fault. I was on a field trip led by Midland Valley Exploration, Ltd. I like this rock because it is part of the classic “Old Red Sandstone,” which I had never seen in outcrop. I find it intriguing that this pebble does not simply fall apart, given all of the faults that cut it. Instead, there must be ‘cement’ sealing the faults, a cement deposited during deep ground water circulation or even syntectonic precipitation of vein material.
Age & Formation
Pebble from the Old Red Sandstone, Devonian age, ~380 Ma.