This article describes the geology of the Broads, an area of East Anglia in eastern England characterised by rivers, marshes and shallow lakes ('broads').
Extraction of the peat in historic times, and subsequent flooding of the workings, has resulted in the pattern of broads for which the area is widely known.
Borehole, seismic and other geophysical survey evidence suggest that the entire region is underlain at depth by rocks of Silurian age though these do not occur at or near the surface.
It left a series of river terrace deposits, evident west of Geldeston for example, whose colours betray the origin of their materials in the English Midlands.
The tract of country around Lowestoft, Belton and Blundeston is formed by sands, along with sandy clays and gravels, formerly assigned to the Corton Formation.
The silts and clays of Flandrian age together with peat deposits forming the broad flats of the various river valleys are collectively assigned the name of the Breydon Formation.