The term "calcareous" refers to a substance or material that contains a high proportion of calcium carbonate, or that is related to, consisting of, or containing calcium, as in calcareous soils, rocks, or organisms. Calcium carbonate is a common mineral that is found in many natural materials, such as limestone, chalk, and marble, as well as in the shells and skeletons of many marine organisms. Calcareous materials are often associated with alkaline conditions and can have important implications for soil fertility, plant growth, and the ecology of aquatic systems.
