Korrelaag

Korrelaag is a stratigraphic term for a distinct, laminated horizon within sedimentary sequences. The layer is typically dark in color and enriched in fine organic matter, presenting contrasts in texture and mineralogy with adjacent beds. In regional stratigraphic literature, korrelaag is used as a practical marker for correlation across boreholes and outcrops.

Formation and characteristics: Korrelaag forms during relatively brief intervals of accelerated fine-sediment deposition, often in wetland or lake-margin settings. These events produce a well-defined, laminated horizon with sharp upper and lower contacts, higher clay and organic content, and distinctive geochemical signatures that set it apart from surrounding sediments.

Methods of study: Geologists identify korrelaag through core logging, textural analysis, and petrography. Laboratory analyses, including grain-size distribution, mineral assemblages, and stable isotope ratios (for example carbon and oxygen), help interpret the depositional environment and establish relative dating.

Distribution and significance: Korrelaag has been documented in temperate lacustrine and deltaic basins where short-lived sedimentation events occur. When present, the korrelaag serves as a valuable marker horizon that aids in structuring stratigraphic correlations and reconstructing past environmental changes.

See also: Marker horizon, Stratigraphy, Sedimentology.