muodostumat

Muodostumat is the plural form of muodostuma, a term used primarily in geology to describe a lithostratigraphic unit. A muodostuma is a body of rock that exhibits a relatively uniform lithology and can be traced across a region on geological maps, making it a fundamental unit for describing the stratigraphic sequence of an area. Formations are named after a local geographic feature, rock type, or another characteristic locality, and the name is applied consistently across the mapped area.

A muodostuma may comprise several beds and can be subdivided into smaller units called members (jäsenet) or other subunits. The boundaries of a muodostuma are defined by detectable changes in lithology, sedimentary structures, thickness, or by unconformities, and these boundaries are used to correlate rocks over distance and to reconstruct geological history.

In Finnish geological practice, muodostumat form part of a hierarchical framework in lithostratigraphy, alongside other units such as members and beds. They serve practical purposes in bedrock mapping, mineral exploration, and paleoenvironmental reconstruction, providing a consistent language for describing the distribution and properties of rocks.

The concept of muodostuma is aligned with international lithostratigraphic practice, and while the term is most commonly encountered in geology, it can appear in broader discussions of rock formation and description. The plural muodostumat refers to multiple such rock bodies defined by their lithology and geographic extent.