a break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time.
an unconformity in which stratified rock rests upon unstratified rock.
the boundary between a set of tilted layers and a set of horizontal layers.
the boundary between horizontal layers of old sedimentary rock and younger, overlying layers that are deposited on an eroded surface.
a break or crack in the Earth's crust along which rocks shift their position.
is a mass of igneous rock that forms when magma is injected into rick and then cools and solidifies.
Law of crosscutting relationship
the principle that a fault or body of rock is younger than any other body of rock that it cuts through.
the numeric age of an object or event
are layers of alternation coarse and fine sediments.
atoms of the same element that have different numbers of neutrons.
have a nuclei that emit particles and energy at a constant rate regardless of surrounding conditions.