Kalksteine

Kalksteine, or limestones, are sedimentary rocks composed mainly of calcium carbonate (CaCO3). They develop by the accumulation of calcareous skeletal remains from marine organisms and by direct chemical precipitation of carbonate minerals in marine environments. Over time, the sediment becomes compacted and cemented into rock.

Biogenic limestones include fossiliferous limestone, chalk, and oolitic limestone, which form from fragments of shells, corals, and ooids. Travertine and micritic limestone are typical chemical or biochemical varieties formed by precipitation in caves, hot springs, or calm marine waters.

Limestone typically exhibits light colors, varies in hardness around Mohs 3, and effervesces when treated with dilute acid due to calcite. Its porous texture in places makes it susceptible to weathering in surface exposures.

Global distribution is wide; large deposits occur in many regions. Limestone can be altered by diagenesis to marble, or form karst landscapes with caves, sinkholes, and underground drainage; such karst aquifers play an important role in groundwater systems.

Uses include building stone and decorative stone, lime production (calcination to quicklime and slaked lime), and cement manufacture. Ground limestone is also used in agriculture to neutralize acidity.

Economic and environmental aspects: quarrying provides raw materials, but can impact ecosystems; sustainable management and restoration are common concerns.