The remnant of an ancient volcano's central magma pathway that has been exposed by erosion.

The magma in a volcano's central plumbing system cools much more slowly than extrusive igneous rocks because it is cooling beneath the surface. These slower-cooled rocks tend to be more resistent to erosion. Therefore, after a volcano has become extinct and is exposed to weathering and erosion, the flanks get eroded to a greater degree than the old central shaft. This leaves the neck standing exposed.

One example of a volcanic neck is Devil's Tower in Wyoming which is well known due to its appearance in Steven Spielberg's Close Encounters of the Third Kind. Another example is Shiprock Peak in New Mexico. Shiprock Peak is one of hundreds of volcanic necks that can be seen when driving along Route 64 near the Four Corners.

Vol*can"ic neck. (Geol.)

A column of igneous rock formed by congelation of lava in the conduit of a volcano and later exposed by the removal of surrounding rocks.


© Webster 1913

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