Developers are being warned that 'rare geology' vital to research into climate change must not be disturbed if it goes ahead with plans for hundreds of new homes in Norwich.

Natural England is warning developers planning to build more than 200 homes on the former Pinebanks sport and leisure site off Harvey Lane, Thorpe St Andrew.

The organisation, which advises the Government on the natural environment, fears the development could threaten to disturb the 'rare geology'' of a neighbouring gravel pit.

A spokesman for Natural England said: 'The gravel pit is an important regional geological site. Our role is to make sure any rare geology is protected. If we think the development may damage this then we may object to it.

'We want it protected so future generations can benefit from the study of it and reveal more about the earth's past.'

Developers want to build 240 new homes on the three acre Pinebanks site which was bought by Berliet Ltd after the site closed in 2008 leaving many sports clubs without a home.

The site of the former gravel pit, which is to the west of Pinebanks and south of Hill Crest Road, is now covered by grass and flora and contains rock, gravel, sediment and pebbles beneath the surface dating from the Ice Age which could be significant in the study of climate change, according to local experts.

A spokesman for Ocubis Ltd. the site's development managers for Berliet Ltd., said: 'We are aware of this site's importance and are consulting with all the relevant bodies ahead of our pre-application public consultation.

'We will be announcing the dates of the public exhibition shortly, this will be an ideal opportunity for the public to hear about the plan in its entirety.'

Public access to the former gravel pit may be improved if plans for the new homes are given go ahead and would be welcomed by some if the geological importance of the site can be protected.

Phil Courtier, head of planning at Broadland District Council, said: 'It (former gravel pit) is clearly a very special site, if the developers open it up to public it could be a very good thing, as long as it doesn't damage it.

'My understanding is that can be done. They seem very aware of how significant and important it is, I don't think they ever intended to develop on that site, in fact it provides an opportunity to open it up and give local people greater access to a pleasing open space.'

Steven Ford, Thorpe St Andrew town council clerk, said: 'The developers said they won't develop on the gravel pit, but open it up to the public.

'Currently it is not officially open to the public. People go there and enjoy it but there is no legal walkway.

'Developers have no trouble with what Natural England say, if anything their plans would link the pits to the ancient woods and the public right of way that runs into School Lane.

'It will make a nice circular walk.'

Elvin Thurston, of the Geological Society of Norfolk, is a retired chemist and amateur geologist who has carried out studies on sites around Norfolk.

Mr Thurston, who lives on Lenthall Close, near the Pinebanks site, said: 'It is all about understanding climate change in the past, to predict what will happen in the future.

'The orientation of pebbles tells you which direction the water was flowing and where the gravel and stones came from. A picture builds up, of what went on in the past.

'So we can use the site to predict the future of climate change, to workout a mathematical model to see how the climate did work, to predict what will happen.

'The sediment and pebbles found at the site and at places like Mousehold, were deposited by glacial meltwater.

'That is, when ice was melting as temperature changed, you got a lot of water moving, so you got a lot of sand and gravel, running with the water.

'Glaciers would move. Studying the site would answer a question which is big for geologists, of whether the particular glacier was advancing or retreating, and exactly which glacier it was, as the Ice Age had multiple stages.

'Some of the specimens are probably 450,000 years old. This is the only study site left, not that we are against development, but any development would have to take this into account.'