Strategy Area Description

The rocks of the strategy area comprise a series of mudstone, siltstone and sandstone, which sometimes include coal and iron-rich bands within the first of these. In eastern South Tyneside and Sunderland the geology is dominated by the magnesian limestone (forming the cliffs of the South Shields and Sunderland coastline), with smaller amounts of millstone grits and mudstone. The presence of this limestone has a profound influence on the area's ecology. In the south, west and part of the south east, the surface rocks are underlain by the late carboniferous rocks of the coal measures. The economic, cultural and historical impacts of the presence of these cannot be overstated. The eastern hills of Gateshead have an underlying geology that is predominantly sandstone and grindstone.

Over much of the area's bedrock lies various forms of superficial, unconsolidated drift; often till and boulder clay from the last glacial period. At the coast, the limestone is topped by glacial drift and boulder clay. In places, the limestone outcrops influence the vegetational sward to such a degree that the area's most important botanical habitat, magnesian limestone grassland, has developed upon this.

During the most recent sequence of glaciations, the valleys of the Team, Wear and Tyne were carved out. The river's courses were scoured and re-shaped, as ice sheets wore away rock and then some 10,000 years ago, glacial melt-waters gouged out surface deposits and re-distributed vast quantities of sediment over the landscape. It was these powerful forces that blasted a way to the sea through the limestone for the River Wear, and left the topography that persists.

In the west, glacial sands and gravels were deposited along the Tyne and the north-south oriented valleys of western Gateshead. The commercial excavation of these deposits created 'strings of quarries' and post-exploitation, landfill sites.

In the east, much of the drift geology comprises boulder clays, with some sands, overlying the magnesian limestone.  At South Shields, extensive post-glacial, windblown sediment is found along the low-lying coast, to the north of Trow Point.

Across the strategy area there are many locations where the sub-surface deposits comprise 'made ground' of rubble and fill, capped with clay. Some of this came from post-Second World War slum clearances (for example at Jarrow Slake, South Tyneside) or, in many locations, (for example Watergate, Gateshead and Silksworth Colliery, City of Sunderland) from pit waste and spoil heaps.

Soils

Across the strategy area, slowly permeable, seasonally wet, slightly acid but base-rich loamy and clayey soils predominate. There are ten different soil formulations across the area; six of which predominate. Many are of relatively low fertility, matching the area's relatively low agricultural land gradings. There are two dominant soil formulations. The first of these is, "slowly permeable, seasonally wet acid loamy and clayey soils", with low fertility. This covers a large part of the western portion of the Strategy Area; most of the land to the west of the Team valley. The second is, "slowly permeable, seasonally wet, slightly acid but base-rich, loamy and clayey soils", with moderate fertility. This soil type dominates in the easterly portion of the strategy area.

Scattered elsewhere, there is a series of soils more specific to local conditions. For example, on parts of the magnesian limestone plateau "freely draining, lime-rich soils" are present.  Along the southern bank of the river Tyne, around Blaydon, and from there, south west, up the lower Derwent valley are located "freely draining floodplain soils", with a moderate to high fertility. In some parts of western Gateshead, there are examples of 'restored' soil types, on land that was previously subject to open cast mining or quarrying.   

The agriculture practised on these soils varies. The higher fertility more freely draining soils are used for cereals and other arable crops, the heavier nutrient poor soils being left to pastoral systems.