Relative Age To Rocks Flashcards
Absolute age is…
A number of years since the rock formed
Relative age is…
The rock age compared to the ages of other rocks.
Law of superposition is…
Helps to determine the relative ages of sedimentary rock layers. This law basically states that in horizontal sedimentary rock the bottom layer is the oldest layer. Each higher layer is younger then the layers.
Extrusion is…
Magma that flows onto the surface (lava) and hardens.
Intrusion is…
Magma that cools and hardens into a mass igneous rock.
Fault is…
A break on the Earth’s crust/ surface.
What’s uncomfority
The surface wherenew rock layers meet a much older rock surface beneath them.
Index fossils are…
Fossil widely distributed organisms that lived during only one short period of time. Index fossils tell the relative age pf rock because it is compared to other fossils in other locations. Rock layers that contain the index fossils are about the same age. You can also use index fossils to match rock layers.
