fossil
the remains or impression of an organism preserved in rock
rock layer
a horizontal layer of rock, especially one of several parallel layers arranged one on top of another
strata
a layer of rock or soil in the ground
rock cycle
a representation of the transitions made over time amongst the three main rock types
igneous rock
rock formed from cooled, solidified lava/magma
metamorphic rock
rock that has been changed by extreme heat and pressure
sedimentary rock
rock formed through the deposition and solidification of sediment that frequently contains fossils
magma
the molten rock material that originates under the Earth's crust and forms igneous rock when it has cooled�magma that reaches the surface of our planet through a volcano vent is also known as lava
Law of Superposition
in undisturbed rock layers, the youngest layer is on the top and the oldest layer is on the bottom
relative dating
to find out the relative order of past events without finding out the exact date of when the events happened
fault
a break in the Earth's crust that causes one or both sides to move past each other
intrusion
when magma comes up into rocks but does not break the surface
extrusion
when magma comes up into rocks and breaks the surface
index fossil
fossils that are used to define and identify geologic periods
fossil record
the information that has been collected from the total number of fossils that have been discovered