Leeds Geological Association

The Ice Age

Related: Local geology  Fossils  The Leeds hippo  Geology and Scenery  Geology and Man 



Over the past 2 million years or so, the climate of Britain has fluctuated between subtropical and polar. This episode, called the Ice Age, has left its mark on the geology of the area.


Periods of cooling, known as glacials, usually lasted many tens of thousands of years and saw ice grow in highland areas and spread out over the surrounding lowlands. Initially glaciers followed the river valleys, deepening and straightening them. The valleys of the Wharfe and Aire both show signs of this. As conditions got colder, vast ice sheets spread out over all the land.

Leeds 16,000 Years Ago

How Leeds may have looked 16,000 years ago!

Leeds 126,000 Years Ago

Interglacials were periods when the climate warmed up and ice sheets and glaciers retreated. The extent of the retreat varied depending on how warm the climate became. The discovery of the Leeds Hippopotamus clearly indicates that sometimes it was considerably warmer than today's climate.

How Leeds may have looked 126,000 years ago!


As the ice sheets and glaciers retreated they left behind the load that they had carried. This consisted of rock debris ranging in size from huge boulders to finely ground rock flour forming a deposit called till which conceals the solid rock with a blanket of varying thickness. The vast amounts of meltwater released by the decaying ice sheets swept along sands, gravels and muds. In areas of slacker current and temporary lakes these were deposited to form thick beds of silts, sands and gravels.