Some, however, never reaches the surface and forms
Yosemity granite. By
Larry via Flickr.com
Those intrusions have an array of shapes, such as vertical dikes, horizontal sills,
- systems of many plutons.
They can be very spectacular millions of years later when the rock has
been uplifted and the intrusions uncovered by erosion.
The rocks that belong to this group are phaneritic or coarse
grained. Because it is much hotter under the Earth's surface than above
it, the minerals in those rocks get much more time to grow than get the
minerals of rocks that form above the surface.
The rocks that belong to this group are granites, syenites, monzonite,
diorite, gabbro, kimberlite, dunite, peridotite and