Local Geology

Drift

The solid geology of the Midlands is overlain in places by a variable thickness of glacial drift deposits as a result of the Pleistocene ice ages. These deposits can be over 30m thick; however 2-10m is more typical.

Glacial ice appears to have only completely overrun the region once, during the Anglian stage. Glacial ice also affected the north west of the region during the latter part of the Devensian stage 15-20 thousand years ago. It is uncertain whether the ice during the Wolstonian stage affected the region. There are a few relics of a pre-Pleistocene weathering profile in the Midlands; however the Anglian deposits and the solid strata have been affected by intense periglacial processes during the post-Anglian cold stages. Periglacial disturbance in the top 1-2m is common, but the effects of former permafrost can extend to several depths.

The glacial deposits often form a poor or variable material for building foundations. However, the poorly sorted glacial tills, especially if they have been overconsolidated by the effect of former ice cover, usually provide reasonable material for the foundations of two-storey buildings.