Thames Through Time – with a Cornish flavour

Talk by Ian Mercer from the Essex Rock & Mineral Society.

Abstract:

Ian Mercer reveals the story of the Thames across Essex by digging into the landscape in and around the county. The Thames has changed course dramatically and repeatedly throughout the past two million years of the current ice age. The greatest impact of the Thames upon the landscape is during times of cold, when Spring thaws create mighty torrents of water. River-bed gravels have been deposited while the land has been tilting gradually throughout this time, resulting in ‘staircases’ of gravel terraces across the landscape and beneath the temporary flood of the North Sea.

During this time, the rivers have brought rocks from across the area of southern Britain as evidence of their journeys. These include beautiful black-and-white pneumatolytic quartz-tourmalinite from around the granite intrusions of the South-West. Ian has collected many of these from across Essex and East Anglia and has grown to love them. He reveals their evidence in the land and in church walls. The Thames will change again many times as climate continues to oscillate.