Clastic Dikes Form Polygonal Networks

Networks of Pleistocene clastic dikes are sometimes visible on bladed slopes or surfaces that have had all vegetation removed.

Aerial photo shows a dike network translating through a bladed slope along I-82 near the Best Western at Sunnyside, WA. Google Earth photo, May 2015.

Photointerpretation of the dike network. Denser vegetation grows atop the dikes, making them darker.

Taller grasses highlight the dike network in Touchet Beds. Google Street View photo.

A 2005 photo of a working farm along Sunnyside-Mabton Road, built on Touchet Bed sediments. The farm existed until at least 2006.

A 2018 photo of the same land with the farm completely removed. The vegetation west of the road a decade later appears to highlight a polygonal pattern formed by clastic dikes...or is it just a sprinkler pattern?

Sprinkler pattern for reference.

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