Greater Lincolnshire’s diverse geology (or ‘geodiversity’) provides a rich variety of landscapes and environments. The lowlands are underlain by clays and mudstones with superficial deposits of glacial till, fluvial sands and gravels, coversands, peat and estuarine/marine silts, giving a distinctive character to each area. These produce the fertile soils that are so important for agriculture, particularly in the south.

Three upland ridges run almost parallel, north to south, through Greater Lincolnshire. In the northwest an ironstone ridge, formed on an undersea slope, can be seen in the Scunthorpe area. To the east is a prominent limestone ridge that gradually becomes higher as it runs south; Lincoln Cathedral sits atop this ridge. Further to the east is the chalk ridge of the Wolds, which provides the well-known vistas of the county’s only Area of Outstanding Natural Beauty  (AONB).

During the last 2.4 million years, Greater Lincolnshire has experienced several periods when it was much colder than the present day and periods when it was significantly warmer. During the coldest climate sea level was much lower than at present and the land area extended into what is now the North Sea. Evidence of this can be seen in the submerged forests on the various beaches popular for tourism along the coast.