Standing like soldiers at attention, the palisades of the Columbia Basin can be seen stretching for miles and miles through Oregon and Washington. They were formed in an unimaginably huge volcanic flow that lasted from 17 million years ago to around 6 million years ago, and took their shape as water cooled the lava and shrunk the molecules.
The crystalline nature of the stone tends to separate into polygonal shafts which become more pronounced due to weathering over time. Some other local examples of basaltic columns include the miles of sea stacks along the Northwest Pacific Coast.
These columns are ready-made pieces of natural sculpture when included in a landscape design. You may have seen some of these formations used as fountains, a hole drilled through the center to form a water spout.
This photo to the right is part of a large installation we did on Mercer Island in which 20 tons of column were arranged vertically and planted with succulents and vines. This variety of column is referred to as “quarry block” because it is taken from an area of flow that contains many tiny shafts that are at times singular 4″-wide sticks and in other cases bound into huge, fluted chunks.
For more information about Columbia River Basalt, take a look at http://hugefloods.com/.
The best supplier in the area for basalt columns (as well as basalt pavers, benches and sculpture) is Coverall Stone in Downtown Seattle. They supplied the stone for this project, and they are very knowledgeable about the best way to install and care for it.
Coverall installed this very impressive arrangement of quarry block at the Convention Center in Seattle. It was the inspiration for the one that we installed.
by Mark Shepherd www.ShepherdStoneworks.com
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