Speaker Meeting Mr Ian Mercer 

Subject: 'Hornchurch on Thames' 

when the River 

flowed  across Hornchurch

Ian is a retired geologist and gemmologist who can’t stop talking about landscapes, rocks, crystals and gems. He gained his degree in geology and X-ray crystallography at Birkbeck College, University of London and is a Fellow of the Gemmological Association. Ian worked for the Geological Survey and Museum and then the Gemmological Association, travelling the UK and the world to catch sight of its many wonders - from jade to gravel. He found plenty of gravel back home in Essex and likes to help people wonder why it’s here! 

Ian Mercer's talk Hornchurch on Thames reveals the story of the River in its varied routes across Essex. 

The Thames has changed course dramatically and repeatedly throughout the past two million years and once flowed over the area of Hornchurch. We are in the middle of a long Ice Age, a sequence of many oscillations in climate between warm and very cold. The greatest impact of the Thames upon the landscape is during times of cold, when Spring thaws create enormous torrents of water. Throughout this time river-bed gravels have been deposited while the land has been rising and tilting; this creates a ‘staircase’ of gravel terraces, seen in the landscape and beneath the transient flood of the North Sea. Ian shows evidence in the land and even in church walls. The Thames will change again many times as climate continues to oscillate. 

More Info ....

http://www.erms.org/news.html