The Process of Sedimentary Rock Formation
The cliffs of Dover are made of sedimentary rock. Here is a guide to it:
The process of sedimentary rock formation takes hundreds of years and is a slow process. It begins
initially with igneous, metamorphic and other sedimentary rocks. Once these rocks get exposed to
the earth’s surface, the formation of sedimentary rock occurs slowly but relentlessly. The formation
of rocks occurs through many processes. Weathering is one such process.
All types of rocks are subjected to weathering and the process of weathering brings about the
breaking of rocks into smaller pieces or sediments. This is brought about by weather conditions such
as high wind, rain and the freezing of water.
Deposition is the process by which sediments which are formed through weathering is deposited or
carried to other places by wind, gravity and running water. When these forces loose energy, the
sediments settle out of water or air. When settling occurs the rock fragments would be graded by
size. Settling of the heavier particles our first. The fragments which are very small travel the farthest
settling out last. This process of settling is termed deposition.
Sedimentation could occur due to erosion which is the combination of weathering and movement
resulting in sediments. Lithification can be termed as the changing of sediments into rock and it
occurs as two processes, which is compaction and cementation.
Compaction could occur after the sediments are deposited. Due to the weight of the sediments, the
particles are squeezed together. When more and more sediments get deposited, the weight of the
sediments which are below increases. The waterborne sediments gets tightly squeezed together
which pushes out most of the water. The process of cementation occurs when dissolved minerals get
deposited in spaces between the sediments. The sediments are bound together by these minerals
which act as a cement or glue keeping the sediments together.
The formation of sedimentary rock takes hundreds and thousands of years to come to a completion
which only help in the formation of a new cycle of rocks. The rock cycle can be described as the
process which earth uses to recycle the soil and rocks which make up the different layers. During the
rock cycle the rocks continually change form and what starts off as a sedimentary rock could change
to metamorphic and through time and weathering change back into sedimentary. The sedimentary
rocks could turn out to become igneous rocks as they get pushed down from the surface of the earth
into intensely hot inner layers of the earth.