Sedimentary Rock
To understand the geology of the Cliffs of Dover you need to understand the geology of sedimentary rock:
Sedimentary rocks can be described as various forms of rock which are formed due to the deposition
and subsequent cementation of these materials on the surface of the earth and within water bodies.
Sedimentation can be defined as the name given for the processes which cause mineral or organic
particles detritus to settle properly. Thus, the particles which form sedimentary rocks through the
process of accumulation is called sediment and it could be deposited by sedimentation process
which is weathering and erosion from the source area and is then being transported to the place of
deposition through mass movement, glaciers as well as ice, water and wind. These agents are called
denudation. The process of sedimentation could also occur when minerals precipitate from water
solutions or the shells of aquatic life settling out of suspension.
It is observed that the sedimentary rock which is covering the earth’s crust across all continents is
vast, amounting to almost 73% of Earth’s land surface. However the total contribution of
sedimentary rock is only 8% of the total volume of the crust. These sedimentary rocks form a thin
veneer above the crust which is mainly made of metamorphic or igneous rocks. The sedimentary
rocks deposit as layers forming the bedding which makes up strata. An understanding of the
sedimentary rocks as well as strata is important for civil engineers who need information about sub
surfaces which is needed for construction of tunnels, canals and roads. Sedimentary rocks also form
a vital component of natural resources such as fossil fuels, ores and other minerals and coal. When
we look into the sedimentation and sedimentary rock, one is able to understand the earth’s history
which includes palaeogeography and paleoclimatology which helps to understand the history of the
life of the earth. Sedimentology helps in studying the origin of sedimentary rocks and is a part of
physical geography and geology which overlaps with other disciplines in Earth Sciences such as
geochemistry and structural geology. Not just on earth, sedimentary rock is present in planet Mars
as well.
It is important to note that sedimentary rocks are classified based on origin and that it can be further
subdivided into 4 groups based on the processes which is responsible for its formation. These are
clastic sedimentary rocks, chemical sedimentary rocks, biochemical sedimentary rocks and other
sedimentary rocks which are formed due to the impact of volcanism and other minor processes.