Clastic dike

Clastic dikes form rapidly by fluidized injection (mobilization of pressurized pore fluids) or passively by water, wind, and gravity (sediment swept into open cracks).

Formal geologic reports of clastic dikes began to emerge in the early 19th century.

Clastic dike environments include: Tens of thousands of unusual clastic dikes (1 mm–350 cm wide, up to 50 m deep) penetrate sedimentary and bedrock units in the Columbia Basin of Washington, Oregon and Idaho.

The silt-, sand-, and gravel-filled dikes in the Columbia Basin are primarily sourced in the Touchet Formation (or the Touchet-equivalent Willamette Silt) and intrude downward into older geologic units, including:

In 1925, Olaf P. Jenkins described the clastic dikes of eastern Washington state as follows:[61] It appears, then, that in every case fissures formed and then fragmental materials are dropped, washed, or pressed into them, from above, below, or from the sides.

Vertical clastic dike, filled with coarse basaltic sand, cuts lighter-colored horizontal beds composed of finer grained material. Quarter for scale.
Red-colored clastic dikes injected downward into light-colored sediment beneath a debris flow . Black Dragon Wash, San Rafael Swell , Utah
Clastic dike exposed on the east flank of the central peak of Upheaval Dome , Canyonlands , Utah . The sandstone dike was injected downsection from the White Rim Sandstone into the Organ Rock Shale during the earliest part of the impact crater excavation stage. The dike is made of cataclastically broken sand grains derived from the White Rim Sandstone. The slightly overturned Organ Rock beds dip steeply to the left and their tops face toward the right. The White Rim Sandstone, folded to vertical, lies just off the photo to the right. View is to the north. P.W. Huntoon Collection.
Vertically sheeted clastic dike typical of those found in rhythmically bedded Missoula floods slackwater deposits of the Columbia Basin . Yellow field book for scale. Willow Creek Valley at Cecil (Oregon) .