Country rock (geology)

For the musical genre, see Country rock.
All of "Devonian and younger", "Silurian", and "Ordovician" are country rock. The igneous intrusion leads to a volcanic eruption.

In geology, country rock is the rock native to an area, in contrast to any intrusion of viscous geologic material, commonly magma, or perhaps rock salt (in salt domes) or unconsolidated sediments.[1]

A dike (dark) intrudes into the country rock (light), Baranof Island, Alaska, United States

Magma is typically less dense than the rock it intrudes, widening and filling existing cracks, sometimes melting the already-existing country rock.[2]

The term "country rock" is similar to, and in many cases interchangeable with, the terms basement and wall rocks.

Country rock can denote the widespread lithology of a region in relation to the rock which is being discussed or observed.

  1. ^ "Country rock - encyclopedia.com". encyclopedia.com. Retrieved 16 December 2018.
  2. ^ Earle, Steven (September 2015). "3.5 Intrusive Igneous Bodies". 3.5 Intrusive Igneous Bodies. Retrieved 16 December 2018.