Poststratal

Poststratal is an adjective used primarily in geology and related earth sciences to describe processes, structures, or phenomena that occur after the formation of a stratigraphic sequence. The term combines post- (after) with strat- (layer or stratum) and is employed to emphasize timing relative to sediment deposition and lithification. It is a specialized term and not widely used outside technical literature.

In geological practice, poststratal can refer to events that modify strata after their initial formation. Examples include poststratal faulting or tilting that reorients layers after burial, poststratal erosion or weathering that affects a layer following its deposition, and poststratal diagenetic changes such as late-stage cementation or mineralization that occur after the rock has formed. In some contexts, poststratal metamorphic overprinting is described when conditions change after burial, although metamorphism is often discussed separately as a broader process.

In stratigraphy and sedimentology, distinguishing poststratal alterations from features formed during deposition (syn-stratal) or before burial (pre-stratal) is important. Geological reasoning typically relies on relationships such as cross-cutting relations, unconformities, fossil succession, and dating techniques to establish the poststratal character of a feature.

Etymology and usage: the term is specialized, and many authors prefer poststratigraphic or describe the process without the term poststratal. When encountered, poststratal serves to convey a temporal sequence where changes occur after the primary formation of rock layers. See also stratigraphy, lithology, diagenesis, and unconformities.