Chalk is a type of limestone made of coccolithophore fossils. The construction industry uses these compacted coccolithophore fossils mainly for making lime mortar. Chalk is also used as a building stone while chalk rubble is employed in road construction. Coccolithophore fossils limestone is also used in the production of aluminium, steel, glass and paper.
The study of coccolithophore fossils, which are broadly distributed around the world, is important for the understanding of life in other geological eras, such as the Triassic. As coccolithophores are sensitive to changes in salinity and temperature, their fossils become important indicators of climate modifications in past eras. Coccolithophores produce alkenones, which are compounds that indicate environmental changes.
Coccolithophore fossils that form limestone are used in sculpture, as a component in the production of dry pastels, to draw on canvases, and colored chalk sticks, which contemporary artists use to create graffiti panels on walls and sidewalks. The high concentration of calcium carbonate in coccolithophore fossils is responsible for the softness of many limestone, used to carve artistic panels and create statues.
The lime used in soils before sowing is also made of coccolithophore fossils. The alkaline nature of these fossils, as well as their high concentration of calcium carbonate, make them a common agricultural aid in the treatment of acidic soils. Most plants growing in acid soils can absorb important nutrients, such as nitrogen and potassium.