prograded

Prograded is an adjective used in geomorphology and sedimentology to describe landforms and coastlines formed by progradation, the outward growth of the land due to sediment deposition. Progradation occurs when the rate of sediment supply exceeds the rate at which accommodation space is created, typically as a result of relatively low or stable sea level, tectonic uplift, or subsidence that favors deposition. The net effect is a shoreline or delta front that extends seaward, migrating the shoreline toward the open sea over time. The resulting deposits are described as prograded and often show seaward-dipping clinoforms and stratigraphic onlap or downlap toward the sea.

Prograded coastlines include deltas, beaches, and barrier systems. Progradation can be driven by riverine discharge delivering large volumes of sand and silt, glacial outwash, littoral transport by waves, and coastal uplift that increases sediment supply. It contrasts with retrogradation, where the shoreline migrates landward due to increased accommodation or reduced sediment supply, and with aggradation, where sediment accumulates vertically without significant shoreline advance.

In stratigraphy, recognizing prograded units helps reconstruct past shoreline evolution, climate, and relative sea-level change. In sedimentary and petroleum geology, progradation indicators guide interpretation of depositional environments and aid in understanding stratigraphic traps and reservoir geometry.