Wider significance

Cheviot CragThe Quaternary landscape of the district is one that has increasing significance for the earth science community. Understanding of ice-sheet behaviour is evolving rapidly. Our interpretation of deglaciated landscapes is now heavily influenced by modern polar studies, and this has led to our increased knowledge of the behaviour of the British ice-sheet. Using this increasingly complex model, inferences can now be made about the effects of past climate change on this dynamic ice-sheet, and also on the effects of sea level rise and subtle variations in internal glacial processes. The Hadrian’s Wall country exhibits the classic landscape of a palaeo-ice-stream track, now recognised as being highly significant in the regulation of the mass balance of ice-sheet systems.

The Cheviot fringe area, with its extensive lake, fan and glaciofluvial deposits may provide significant opportunities for earth scientists to add vital pieces of information to our fragmentary record of the period during and immediately after the decline of the last great ice-sheet in Britain. The lake bed of palaeo-Lake Milfield is a potentially vital source of environmental data relating to the collapse and disappearance of the last great ice-sheet in the region, some 15 000 years ago. Lake sediments may contain records as diverse as pollen, diatoms, volcanic ashes or tephras and beetle and plant remains that may give detailed and high resolution information regarding this critical period in recent Earth history.

There are also gaps in our knowledge about the vegetational history and human impact upon it. Particular omissions in the record exist in the north and western parts of Northumberland. Examination of Quaternary deposits, particularly peat habitats, could yield important information. This links to the NNPA archaeological research agenda and should build on previous palaeoenvironmental research in the region.

The Quaternary landscape of the Cheviot massif appears to be very unusual in Britain. It is an upland area that has undergone glaciation during the Quaternary, most recently during the Devensian. However it still preserves features relating to the action of longer term, less physically dynamic processes, i.e. tors and deeply weathered bedrock. The preservation of these normally sensitive features in a landscape that has undergone glaciation is extremely unusual. Understanding why this occurs is a key challenge for future scientists, as it appears to stand contrary to accepted wisdom concerning glacial erosion in upland areas, namely that glaciers perform large amounts of geomorphological work throughout a glacial cycle. If the landscape of the Cheviot massif is inherited from an earlier period of Earth’s history, then this assumption must be challenged.

Geological SSSIs

Quaternary of north-east England:

• Cheviot Tors [NT 956 215]
• Humbleton Hill and Trows [NT 951 275 and NT 963 283]
• Roman Wall [NY 715 667]

Fluvial Geomorphology of England and Wales:

• Harthope Burn [NT 961 230]

Other related biological SSSIs

• Roman Wall Loughs – glacial loughs including the terrestrialised Caw Lough, now a mire
• Border Mires – SAC, internationally important mires