I'm studying Plutonic (Intrusive) rocks and I really don't understand the difference between Plutonic Rocks that form in Sills and Dikes from the so called subvolcanic rocks, also known as a hypabyssal rocks. Aren't they the same? Why?
Main difference between a subvolcanic verses a plutonic is depth at which the rock solidified at from its molten state. Plutonic implies a depth greater than subvolcanic by definition but I am sure there is some overlap between shallow end of plutonic and subvolcanic. Depth of emplacement for plutonic would mostly be much greater than 2 km.
Plutonic is an igneous rock formed by solidification at considerable depth beneath the earth's surface.
Subvolcanic rock, also known as a hypabyssal rock, is an intrusive igneous rock that is emplaced at medium to shallow depths (<2 km) within the crust.