Digger Hire in Chalk

Chalk is a soft, white, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite. Calcite is an ionic salt called calcium carbonate or CaCO₃. It forms below reasonably deep marine conditions from the gradual enlargement of minute calcite shells (coccoliths) shed from micro-organisms called coccolithophores. Flint (a type of chert) is categorically common as bands parallel to the bedding or as nodules embedded in chalk. It is probably derived from sponge spicules or supplementary siliceous organisms as water is expelled upwards during compaction. Flint is often deposited not far-off off from larger fossils such as Echinoidea which may be silicified (i.e. replaced molecule by molecule by flint).

Chalk, as seen in Cretaceous deposits of Western Europe, is uncommon among sedimentary limestones in the thickness of the beds. Most cliffs of chalk have definitely few obvious bedding planes unlike most thick sequences of limestone such as the Carboniferous Limestone or the Jurassic oolitic limestones. This may indicate unconditionally stable conditions more than tens of millions of years.

Chalk has greater resistance to weathering and slumping than the clays later which it is usually associated, thus forming tall, steep cliffs where chalk ridges meet the sea. Chalk hills, known as chalk downland, usually form where bands of chalk reach the surface at an angle, so forming a scarp slope. Because chalk is capably jointed it can preserve a large volume of arena water, providing a natural reservoir that releases water slowly through ascetic seasons.