A Landscape Strategy for Lancashire - Landscape Character Assessment

2. The Evolution of Lancashire

In the Lancashire study area, it is the irregular juxtaposition of contrasting rocks that forms the basic structure of the landscape. But geology is not the only factor to have shaped the landscape; the intricate interplay of geology, geomorphology, pedology, biogeography and human activity have all had a significant influence. Figure 4 shows the range of historic landscape types found in Lancashire; it identifies broad but distinctive patterns of fields, settlements and land cover which have developed through a long history of human habitation and exploitation. The spatial distribution of resources, such as water power, coal, metals, building stone and timber, the development role of technology and the distribution of agriculture are all key influences on the most recent and visible layer of the landscape ^([1]) .

2.1 Physical Influences

2.1.1 Geology and Topography

The underlying geology of Lancashire (Figure 5) is comparatively simple and is formed from four major rock types from three main geological periods. Rocks of the Upper Carboniferous include the Millstone Grit and Coal Measures. The Lower Carboniferous rocks include the limestones of Silverdale and the Ribble Valley which run through Clitheroe into Yorkshire. Permian and Triassic rocks include the sandstones and mudstones which make up the west of the county. The underlying geology, combined with climate and topography, has had a profound influence over the industrial development of Lancashire. Geology is reflected most noticeably in the distribution and variety of building materials used across the county.

These geological strata are covered by layers of glacial and fluvio-glacial sediments which date from the end of the Pleistocene Ice Age. These form a skin of superficial deposits, or drift, which in places are so thick as to eradicate all visual clues as to the nature of the underlying solid geology. This drift is modelled and shaped by fluvial, marine, aeolian and frost processes which combine to create distinctive features and landscapes.

The county can be divided into three broad topographic zones - the lowlands, the uplands and the river valleys (Figure 6). The lowlands are generally formed of Permian and Triassic rocks which are overlain by thick deposits of glacial drift, blown sand, peat, alluvium and silt. These are soft, gently rolling landscapes interspersed with eskers (gravel ridges) and low hillocks (drumlins). Occasionally higher and more irregular relief, such as the ridges around Chorley and Leyland, indicates that the underlying rocks have emerged from beneath the drift. Most of the uplands are formed from Carboniferous rocks which rise high above the plain; they are characterised by features such as boulder erratics. The gritstone plateaux are surrounded by steep glacier smoothed slopes. In the Silverdale area limestone has created a characteristic landscape of crags and valleys and other limestone features.

2.1.2 Natural Features

English Natures Natural Areas, reflect the distribution of wildlife habitats and natural features throughout the countryside as determined by their underlying geology, past land use patterns and the cultural history of individual areas (see Figure 2). They provide a framework for planning and implementation of nature conservation objectives and Biodiversity Action Plan (BAP) targets. Some Natural Areas are conterminous with the Countryside Agencys Countryside Character Areas (CCAs), whilst others encompass two or more Countryside Character Areas.

Box 2.1 Natural Areas in Lancashire - Key Characteristic Habitats 

Figure 7 provides a broad indication of the principal habitats found in Lancashire. Habitats such as moorland, scrub, woodland, pasture, arable fields and marsh are derived from the complex interplay of geology, soil and landform, but the influence of man in clearing and settling the land is a key determinant of land cover and, ultimately, habitat value.

^{([1]) Whittow, John, Geology and Scenery in Britain, Chapman & Hall, 1992}

^{([2]) English Nature, Natural Areas in the North West Region, English Nature, 1999}