jäännöskerrokset

Jäännöskerrokset, a Finnish term, translates to "residual layers" in English. In a geological context, these layers refer to unconsolidated sediments that remain in place following significant erosion or weathering of the parent bedrock. Unlike transported sediments such as alluvium or glacial till, which have been moved from their original location, jäännöskerrokset are found directly overlying the bedrock from which they were derived.

The formation of jäännöskerrokset is a result of the slow disintegration of rock material due to physical and chemical weathering processes. These processes, which include freeze-thaw cycles, chemical reactions, and the action of organic acids, break down the rock into smaller fragments and minerals. Over long periods, these weathered materials accumulate in situ, forming a distinct layer. The composition and thickness of jäännöskerrokset are highly dependent on the type of parent rock, the prevailing climate, and the duration of weathering.

In Finland, where the term is commonly used, jäännöskerrokset are frequently encountered in areas that have undergone extensive glaciation. While glaciers often stripped away much of the weathered material, in some sheltered locations or on less exposed slopes, residual layers could be preserved. These layers can be important indicators of past geological and climatic conditions, providing clues about the pre-glacial landscape and weathering regimes. Studying jäännöskerrokset can aid in understanding soil formation and the geological history of a region.