Age and Movement of Rocks

How old is old? Relative Dating a method of determining if an object is older or younger than another object.

Layer upon Layers a principle that states younger rock layers lay on top older rock layers. Superposition

Column of Ages geologic column the arrangement of rock layers with the oldest at the bottom.

Disturbing Forces Geologic Columns are not always horizontal. Forces from inside the Earth often disturb the layers. There are 4 types of disturbed rock layers.

Disturbed Rock Layers A fault is a break in the Earth’s crust that moves rock layers in different directions.

Disturbed Rock Layers Folding occurs when rock layers are bent and buckle.

Disturbed Rock Layers Intrusions are when lava from inside Earth squeezes into cracks in rock layers and cool.

Disturbed Rock Layers Tilting of rock layers occur when internal forces cause the rocks to slant one direction.

are breaks in the geologic column. 3 types: a. Disconformity (missing sedimentary rock layers) b. Nonconformity (sedimentary on Igneous) c. Angular Unconformities

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