3 May 2012

Big old vesicles!

Posted by Callan Bentley

Today, for your viewing pleasure, I offer you: A series of big honkin’ gas pockets in a 615 ka basaltic lava flow in the Owens Valley of California. This same lava flow has been featured here before, since it imparted a lovely contact metamorphism to the alluvial fan over which it erupted.

These things are weird – they’re all about the same size and the same shape (and the same orientation). They all have these wrinkly bulbous blobs projecting inward. I thought about lava tubes, as I’ve seen similar sized features in Hawaii that were old lava tubes, but these things were not cylindrical — they were round and flat, kind of like a crumpet or a nonpareil.

Anyone want to share some insight on whether these are in fact vesicles, or something else altogether?