Ice Age Essex

Join retired geologists Ian and Ros Mercer on a journey through Essex's extraordinary Ice Age past.

Discover how millions of years of changing climates, advancing ice sheets, powerful rivers and shifting landscapes have shaped the county we know today.

We are currently living within a long Ice Age, marked by repeated swings between warmer and much colder conditions. During the coldest periods, spring thaws unleashed vast torrents of water that dramatically reshaped the landscape. As rivers carved their way through the county, they left behind layers of gravel that now form distinctive 'staircases' of terraces across Essex. For a brief period, much of the county lay beneath an ice sheet, which deposited a blanket of glacial till that can still be found today.

From rocks and pebbles to coastal cliffs, rolling countryside and even church walls, Ian and Ros will show how evidence of this remarkable history is hidden in plain sight. Explore how Essex has changed over time, and what future climate shifts could mean for the county's landscape.

Part of Chelmsford Science Festival 2026.

About our presenters

Ian and Ros Mercer are passionate geologists who admit they simply can't stop talking about rocks and landscapes. Both studied geology at Birkbeck, University of London, graduating in the same year. Ian went on to work for the Geological Survey and Museum before becoming Director of Education at the Gemmological Association. Ros worked as a geophysicist and petroleum geologist, interpreting North Sea seismic data, before later teaching geology and physics.

Together, they have travelled widely in search of geological wonders, from jade deposits to mountain ranges and ancient fossils. Yet some of their favourite discoveries are much closer to home. Fascinated by the abundance of gravel across Essex, they now enjoy helping others uncover the stories hidden beneath our feet.