Sedimenttisten

Sedimenttisten is a fictional term used in geoscience education to describe a hypothetical sedimentary feature embedded in fine-grained sediments such as mudstones and siltstones. It denotes a distinct, lens- or circular-shaped body that displays a characteristic internal structure of concentric laminae or radial patterns, with a boundary rind of cemented material. In appearance, sedimenttisten masses are typically a few to several tens of centimeters across and can range in color from light gray to brownish tan, depending on mineral content.

The name is a compound formed from sediment and a suffix intended to evoke a stone-like concretion; it is not associated with any real mineral species. The proposed formation of a sedimenttisten is attributed to episodic diagenetic precipitation around a central nucleus, possibly organic or mineral, under low-energy depositional conditions followed by burial and chemical alteration. Microbial activity may contribute to pore-water chemistry that promotes cementation, though the exact steps are intentionally ill-defined in teaching contexts.

In a didactic framework, sedimenttisten are used to discuss how diagenesis can alter primary sedimentary fabrics, create sharp facies boundaries, and record past hydrodynamic or pore-water conditions. They are not reported as established natural occurrences in peer-reviewed literature, but are presented as a thought experiment to compare with real features such as concretions, nodules, oncoids, or varves.

Related topics include concretions, nodules, diagenesis, and sedimentology.