Fluviolacustrine

Fluviolacustrine refers to a geological environment or deposit that is influenced by both fluvial (river) and lacustrine (lake) processes. This term describes areas where rivers enter or exit lakes, leading to a complex interplay of depositional forces. Sediments transported by rivers are deposited in lake environments, or sediments from lake bottoms can be reworked by riverine currents.

These environments are characterized by a mixture of sediment types, reflecting both the energy of the river and the calmer conditions of the lake. Fine-grained materials like silt and clay are typically deposited in the lacustrine portion, while coarser sediments such as sand and gravel may be found closer to the riverine input or in areas of higher current velocity within the lake. Features like deltas, where rivers build out into lakes, are prime examples of fluviolacustrine settings. Other indicators include sedimentary sequences showing alternating layers of coarser, channelized deposits and finer, horizontally-bedded lacustrine strata. Understanding fluviolacustrine deposits is important for interpreting past landscapes, identifying potential sources of groundwater, and exploring for mineral resources.