Bergkärna

Bergkärna is a geological term used in Swedish to denote the innermost, most coherent portion of a rock mass or mountain core. The word combines berg (rock or mountain) and kärna (core). In geological descriptions, bergkärnan refers to the central bedrock body that remains after less durable outer units have been removed by erosion or tectonic exhumation.

The bergkärnan often consists of ancient crystalline rocks such as granitic or metamorphic components, and it may preserve the original lithology of the crust in contrast to surrounding, deformed, or overprinted rocks. Its identification helps geologists understand crustal architecture and the tectonic history of a region, including the sequence of rock formation and subsequent modification.

In field and map descriptions, exposures may be described as comprising a bergkärna beneath younger, overlying units. It is a descriptive concept rather than a formal stratigraphic unit, used to communicate the presence of a stable, central core within a larger, more complex rock mass.

The term is primarily used in Swedish-language geology, and in English-language literature it is often translated as “rock core” or “crystalline core,” depending on the context.

See also: bedrock, crust, metamorphic core complex, mountain building, tectonics.