Breaking New Ground

Reconnecting People with The Brecks

Origins of the Landscape

The Brecks Earth Heritage Trail tells the deep environmental history of the Brecks landscape. Rocks, sediments, landforms, fossils and soils all have a story to tell, and evidence for past life – including humans – is woven into it

Sandy heathland at Icklingham Plains, Image courtesy British Geological Survey Geoscenic P212237

The Brecks is founded on Chalk bedrock about 90 million years old. The rock contains a huge reserve of precious groundwater which feeds agriculture and the public water supply as well as rivers and springs. It is also the source of raw flint nodules.

An underground gallery cut into the Chalk by prehistoric flint miners at Grimes Graves. TD Holt-Wilson

The now-vanished Bytham River once flowed through the southern Brecks about ½ million years ago. It drained the Midlands, and evidence for its passing can be seen in a distinctive suite of exotic rock-types brought to the area.

A quartzite erratic, originally from the Midlands, in the wall of Fornham All Saints’ church

The Anglian glaciation set the scene for today’s landscape about 450,000 years ago. Massive ice sheets bulldozed their way across the area, flattening the chalk hills and depositing a range of sediments ,including sands, gravels and a chalky-sandy till, a mixed deposit which now form the Brecks plateau.

Flint boulders in Anglian glacial gravels, Lynford.

After the Anglian ice sheet retreated, rivers developed on the glaciated landscape. The climate warmed up into the Hoxnian interglacial period about 420,000 years ago. Valleys formed, and the human species Homo heidelbergensis colonised the area. They left traces of their passing in the form of flint tools and evidence of their camp fires, as at Beeches Pit, Icklingham. There followed several warm and cold climatic cycles, each one lasting many thousands of years. With each cycle the land surface was eroded and sediment and soil moved downslope into the valleys. River terraces were formed, as benches along valley sides marking former floodplain surfaces. About 160,000 years ago, another glaciation left its mark on the Brecks; spreads of sand and gravel along the margins of Fenland are thought to be the remains of deltas formed at the ice front, as at Maidscross Hill.

A Palaeolithic handaxe from Icklingham. Image from "Ancient Stone Implements" by J. G. Evans (1897)

The Brecks has several nationally important sites where geology and archaeology come together to tell the story of the environment and early human settlement. A fascinating range of wildlife was able colonise the area during the warmer or milder climatic periods. It included Neanderthaler and Heidelberger human species. Evidence for past life is preserved in river valley sediments or in hollows in the chalk. As well as flint tools, we have bones, teeth and tusks, plant remains and pollen, snail shells, beetle remains and other fossils. All these have been uncovered by quarrying or research excavations.

Woolly mammoth, wolf and reindeer were among the inhabitants of the Brecks in the Devensian cold period. Neanderthalers could visit here in milder phases, as at Lynford. Image courtesy Beverly Curl

Woolly mammoth, wolf and reindeer were among the inhabitants of the Brecks in the Devensian cold period. Neanderthalers could visit here in milder phases, as at Lynford.

A woolly mammoth tusk from river gravels at Lackford Quarry. Photo courtesy Ipswich Museum R. 1989.93.

The Devensian period ended about 10,000 years ago. Distinctive landforms such as ground-ice depressions (pingos) and patterned ground (soil stripes) are a legacy of periglacial conditions, as are the layers of coversand (windblown sand and silt) deposited from dust storms blowing across the sparsely vegetated ground. Topsoil in the Brecks has been unstable in more recent centuries, due to the effects of arable cultivation, sheep farming and rabbit warrening on fragile soils. Mobile dunes and sand sheets were active in the Brandon area in the 17th century.

Layers of windblown sand lie just below the surface in many parts of the Brecks.

The Brecks is an area with a distinctive biodiversity and cultural history. Understanding Earth heritage helps explain these as well as the origins of the landscape. New research techniques such as LIDAR mapping are revealing geological landforms in fascinating detail. Here, a digital terrain map of the Little Ouse valley in the Santon Downham area shows details of landforms dating back to the last ice age, including dry valleys, river terraces flanking the valley and a notable meander bluff. The floodplain has developed over the last 10,000 years.

For more information, see the BNG LiDAR project page

Image © Environment Agency copyright 2016. All rights reserved.

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