Columnar-jointed basaltic lava flow at the Narrows of the Grand Can...
Detailed Description
olumnar jointing is seen in The Narrows of the Grand Canyon of the Yellowstone. These columns formed as a result of a basaltic lava flow contracting while cooling. The basalt flow lies on fluvial gravels and later was erosionally truncated at the top of the columns, now overlain by glacial deposits.
Sources/Usage
Public Domain.