Cementerat

Cementerat is a Swedish term used in geology to describe sediments or rocks in which grains are bound together by mineral cement as a result of diagenetic cementation. The adjective refers to the end state after pore-water minerals precipitate and bind the framework grains, producing a coherent rock.

Common cementing minerals are calcite, silica (microcrystalline quartz or chalcedony), and iron oxide minerals. In sandstone, for example, these minerals can fill the pore spaces between sand grains and cement them together, creating a rock with reduced porosity and increased strength. Cementation can produce textures ranging from lightly cemented grains to dense, lithified rock.

Formation and effects: Cementation occurs during diagenesis after initial deposition and compaction. It depends on burial depth, temperature, pressure, groundwater chemistry, and the availability of cementing minerals. Cementation tends to decrease porosity and permeability, affecting fluid flow in aquifers and hydrocarbon reservoirs, although it can also contribute to the mechanical durability of the rock.

Usage and interpretation: In sedimentology, the term cementerat describes the rock’s characteristic as being bound by mineral cement, reflecting diagenetic history and the conditions under which the rock formed. The degree and type of cementation are important for understanding reservoir quality, rock strength, and the geological evolution of sedimentary basins.