Limestone

Rock Database
Fossil Example
Modern Environments

Limestone is formed in marine environments where bits of shell and other debris composed of calcite are deposited on the bottom. Chemical reactions between calcium and bicarbonate ions may also form carbonates, which settle to the bottom. The calcite and other minerals may harden into limestone. Remains of animals may also be buried in the carbonate muds and eventually turn into fossils. Over time uplift and lowering of sea level may expose the limestone layers at the Earth’s surface.