Description of the dominant process on surface, involving movement of large "chunks" of crust relative to each other.

These "chunks" are known as , an apt description since they are both broad and thin, that is, making up large fractions of the Earth's but otherwise only are only as thick as that crust. The ideas of Uniformitarianism have come to be associated with those of plate tectonics as also can many catastrophic events, particularly and .

Dramatic changes in the location of areas on the Earth's surface occur as a consequence of the movement of plates, with this movement the basic underpinning of the ideas of plate tectonics. Such movement is essential towards appreciating Earth's as well as the evolutionary . See, e.g., Pangaea.