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Sedimentary
Rock
Sedimentary rock is the gradual erosion and compression of rock particles. First, rock is weathered away by chemical weathering, biological weathering and/or mechanical weathering. Then erosion happens, and the particles are carried away to river, ocean, and/ or lake bottoms. Finally, there is so much sediment deposited upon top of each other, the bottom layers begin to transform into solid rock, either by the weight or from chemicals that act like super-glue, and sometimes form "beds" of rock. The Earth's surface is approximately ¾ sedimentary rock, but amazingly in the crust, there is less sedimentary rock than igneous rock. Below is an image of sedimentary rock beds.