-
uplift
erosion
sediment deposited more sediment deposited more sediment deposited more sediment deposited
sediment deposited more sediment deposited and
lithified to form sedimentary rock
rocks deformed by tectonic stress rocks uplifted and eroded
sediment deposited
and lithified
Later, clasts derived from the lower unit
are included in the next later of sediment
Any rock in the
Earth’s crust
Magma intrudes, picking up inclusions
from the surrounding rock, then cools to
form igneous rocks with inclusions
Almost all sedimentary rocks formed from deposits of sediment at the surface of the Earth. Once a sedimentary
bed has been deposited, new sediment settles on top of it. Thus, in undisturbed strata, the oldest sedimentary
rocks will be on the bottom of the stack. Applies only to sedimentary rocks and some volcanic rocks.
Almost all sedimentary rocks formed from basically horizontal deposits of sediment. Thus any sedimentary rock
unit that is no longer parallel to the Earth’s surface had be have been deformed (tilted or folded) after it was
lithified. Applies only to sedimentary rocks and some volcanic rocks.
Some rocks contain broken pieces of other rocks (called inclusions or clasts). The rock that supplied the inclu-
sions must have already existed at the time the rock containing the inclusions formed. Thus, the included rock is
from an older rock. Applies primarily to igneous intrusions and sedimentary rocks.
Inclusion
Original Horizontality
Superposition
