What type of organic limestone?

Organic limestone, also known as biogenic limestone, is primarily formed from the accumulation of biological debris, such as shells, coral, and other calcareous organisms. This type of limestone is typically found in marine environments where conditions promote the growth and deposition of these organisms. The most common varieties include chalk, composed of microscopic coccolithophores, and coquina, made up of shell fragments. Organic limestone plays a significant role in the carbon cycle and can also serve as an important resource in construction and industry.