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History Of Earth Crossword Puzzle

By: Emma Buckley
Across
Magma that hardens on the surface and forms igneous rock.
Geologist use the ___ ___ ________ to determine the relative ages of sedimentary rock layers.
A break in the Earths crust is a ____.
A gap in the geological record.
The ____ ____ of a rock is its age compared to the ages of other rocks.
Down
A fossil that must be widely distributed and represent an organism that existed for a geologically short period of time.
Elements release particles and energy in a process called ______.
When magma cools and hardens into a mass of igneous rock below the surface.
The ____ ____ of a rock is the number of years that have passed since the rock formed.
The ____ of a radioactive element is the time it takes for half of the radioactive atoms to decay.