What is the difference between extrusive igneous rocks and intrusive igneous rocks? Extrusive igneous rocks come from lava, forming at the surface of the Earth and cooling quickly, meaning they form very small crystals. Intrusive igneous rocks come from magma, forming deep underground and taking lon...
Rocks are classified according to characteristics such asmineral and chemical composition, permeability, texture of the constituent particles, and particle size. ... This transformation produces three general classes of rock: igneous, sedimentary and metamorphic. What do geologists use to study different ...
How do you determine nonconformity? Nonconformities are unconformities that separate igneous or metamorphic rocks from overlying sedimentary rocks. They usually indicate thata long period of erosion occurred prior to deposition of the sediments(several km of erosion necessary). ...