Nottinghamshire (including City of Nottingham)
The rocks which form the solid geology of Nottinghamshire occur as a series of north-south trending outcrops, with the oldest in the west and the youngest in the east.
This gradual change in the age of various rocks that make up the County is due to their gentle slope away from the central upland core of England formed by the Pennines.
The oldest rocks belong to the Upper Carboniferous Coal Measures and occur on the western border of Nottinghamshire in the Erewash Valley. These form part of the much larger Derbyshire and Yorkshire Coalfields, which extends below younger aged rocks through much of western Nottinghamshire. The mudstones, coals and sandstones of the Coal Measures are overlain by the Magnesian Limestone, which is of Permian age, and which forms a shallow escarpment running up from Nottingham through Mansfield and intermittently up to Oldcotes. This magnesium-rich limestone was deposited on the edge of a shallow marine sea and is composed of the shells of millions of many small sea-creatures and corals.
The succeeding red Triassic sandstones of the Sherwood Sandstone Group outcrop through central and eastern Nottinghamshire. These sandstones contain a large number of quartzite pebbles which were deposited by extensive ephemeral rivers that crossed the desert plain over which the sands were deposited. The porous nature of the Sherwood Sandstone gives rise to free-draining soils throughout its outcrop area, which includes the celebrated Sherwood Forest. Vegetation typical of free-draining soils, such as heathland was once extensive in the Sherwood area, but much of this has now been replaced by conifer plantations and/or put to agricultural use.
The solid geology of much of the central and eastern part of the County is dominated by the mudstones of the Triassic Mercia Mudstone Group, which give rise to the relatively flat, undulating landscape through which the River Trent has cut its wide floodplain. The eastern border of the County is marked by a change to the thick blue clays of the Lias of Lower Jurassic age. These floor the eastern side of the Trent Vale in the north and the Vale of Belvoir in the south-east. The clay soils of these valleys support fertile farmland and scattered woods. Areas of open water along the course of the Trent represent former workings for gravel, huge quantities of which were deposited by the meanderings of the river over the past 15,000 years.
Carboniferous
The oldest rocks found within Nottinghamshire belong to the Carboniferous Period (354-290 million years old) and occur along the extreme western edge of the County in the Erewash Valley. These are the Upper Carboniferous Coal Measures and form part of the Yorkshire and East Midlands Coalfield, the largest and most productive in the UK. In the west, the coal measures outcrop and form the ‘exposed coalfield’ whereas in the east they become ever more deeply buried and the coalfield is said to be ‘concealed’. The rocks of the Coal Measures were deposited on a series of low-lying, swampy deltas on the edge of the shallow Upper Carboniferous sub-tropical sea. The periodic flooding and building of the deltas along the coastline resulted in the deposition of a series of layers of coals (representing the compressed remains of the luxuriant swamp vegetation) interspersed with layers of shale, clay, sandstone and mudstone.
Permian
The succeeding Permian (290-248 million years ago) Period is represented in Nottinghamshire by the Magnesian Limestone, which is so named because the rock contains the magnesium rich mineral ‘dolomite’. This limestone was deposited in a relatively shallow landlocked sea extending from northeast England to Poland, known as the Zechstein Sea. The estimated average temperature during the period was approximately 23°C. Due to the landlocked nature of the sea and high temperatures, deposits of gypsum and anhydrite (collectively known as evaporites) derived from evaporation of the seawater, are found throughout the rock sequence. In Nottinghamshire, the main Magnesian Limestone outcrop occurs between Mansfield Woodhouse and Bulwell and forms some of the most dramatic landscape features in the County, where river action has produced a number of steep valleys and gorges, for example, at Creswell Crags and Pleasley Vale.
Triassic
Rocks of Triassic (248-205 million years old) age form the solid geology throughout the bulk of the central portion of Nottinghamshire. The Lower Triassic sandstones of the Sherwood Sandstone Group cover nearly a quarter of the County, occurring as a broad belt between Nottingham and South Yorkshire. Soils derived from the sandstone tend to be free-draining and slightly acidic and typically support heathland and oak-beech woodland. This is the natural vegetation of the Sherwood Forest area which is underlain by these Triassic sandstones, although the relatively low productivity of the soils means that they are also very well suited to the growth of coniferous trees for timber. The sandstone is also a major aquifer, and serves as an important water supply for a wide area over Central England. During the Lower Triassic all the continents had moved together to form the supercontinent Pangaea (‘all Earth’) and in the area occupied by Britain, arid, desert conditions predominated. Evidence from localities in Nottinghamshire and elsewhere show that the Sherwood Sandstone was deposited on a large desert plain across which large braided rivers intermittently coursed.
The mudstones of the succeeding Triassic Mercia Mudstone Group probably represent wind-blown dust that settled in shallow salt-lakes and sun-baked mudflats on the extensive alluvial plain. These mudstones which are up to 300 metres thick, outcrop over much of eastern and southern Nottinghamshire, and contain nationally important deposits of gypsum. Evidence that the ocean was never far away from the edge of the desert plain at this time is provided by muds and silts in the Mercia Mudstone (as exposed at Colwick) which preserve fossil intertidal ripple marks and the fossils of burrowing shallow marine shells.
Jurassic
Along the eastern boundary of Nottinghamshire, from Rempstone to Clifton, the Triassic Mercia Mudstones are overlain by clays and limestones of the Lower Jurassic (205-142 million years old). These rocks belong to the Lias and were deposited as layers of mud and sand in warm, tropical shallow seas which covered much of central England at this time. Although there are very few exposures of the Lias, where the blue clays have been exposed in small pits and quarries they have yield many fossils including ammonites, bullet-like belemnites (the internal shell of extinct squid-like animals) and bivalves.
Quaternary
Over the last two million years the climate of Britain has varied tremendously with periods of temperate climate interrupted by repeated advances and retreats of glaciers and ice sheets. Collectively these periods have become known as the Ice Age (we are still in one of the temperate phases) and the actions of the ice sheets have been instrumental in forming the landscape we see today.
The most extensive Quaternary deposit found in Nottinghamshire is till (or boulder clay), which is formed in and beneath glaciers and ice-sheets. Nottinghamshire was influenced by the melting and refreezing of ice sheets from at least two different directions during the last glacial (the Devensian, some 20,000 years ago). Ice from the north and the Irish Sea area deposited till containing Carboniferous rocks and other boulders clearly derived from northern England, while in the east of the County till rich in chalk and flint indicates deposition by ice from the North Sea area. Some indication of the types of animals living in the area around the time of the last glacial is provided the remains of fossil cave-lion, bear, mammoth, rhinoceros that have been recovered from Church Hole, one of the Magnesian Limestone caves of Creswell Crags.
Large areas of river-deposited silt or alluvium occur in the river valleys, but in particular the Trent Vale. Here, these alluvial deposits give rise to fertile soils that are agriculturally very productive. Coarse gravels deposited when the river was much larger following the melting of the last great ice sheet some 12,000 years ago, occur throughout the Trent Valley. In some places these gravels occur above the level of the highest floods of today and represent the deposits of the river when it was at a greater height.
Geological Highlights:
- In the past Magnesian Limestone from the Mansfield area was widely used as a building material both locally and nationally. Notable examples of its use include Southwell Minster, Ely Cathedral and the lower courses of the Houses of Parliament. In the Linby and Bulwell area the limestone takes on a very different character and is known locally as ‘Bulwell Stone’. Here the rock is very impure, coarse grained and flaggy. It serves as a good ornamental building and rockery stone.
- In Nottinghamshire gypsum is present throughout the Mercia Mudstone, but commercial interest is restricted to two distinct deposits found in the upper 40m of the sequence, known as the Newark and Tutbury gypsum deposits. The Newark gypsum has a long narrow outcrop rarely more than 2 kilometres wide, extending from Newark to Cropwell Bishop and is the source of high purity gypsum. This outcrop comprises up to 7 commercially viable seams of no more than 1m thickness and thus opencast extraction is the only feasible method of working. In contrast, the Tutbury gypsum normally comprises a single seam which is on average 3m thick. This seam is found to the south-west of the Newark deposit, and extends across much of Nottinghamshire east of the Soar Valley and south of Gotham and Bunny. The Tutbury seam is of lower quality and is used mainly in plaster, plasterboard and cement manufacture.
- During quarrying or mining for gypsum, large compounded blocks are sometimes encountered. This is alabaster, which in Nottinghamshire is found in thick nodular beds or “floors", in spheroidal masses known as “balls” or “bowls", and in smaller lenticular masses termed " cakes". The discovery of large accessible and workable deposits of this mineral around Nottingham at the end of the 14th century led to the formation of a notable tradition of carving of religious figures. This was initiated, in part through increased prosperity following the Black Death, and the aspirations of people to demonstrate their gentility and guarantee their place in the afterlife via a contribution to their local church. The soft alabaster was easy to carve and many beautiful and intricately carved pieces ended up in churches throughout the region and England. During the 14th and 15th centuries, carved alabaster, from small votive statues to the Virgin to large funerary monuments and tombs, was exported from Nottingham all over European Christendom, from Iceland to Spain.
- Nottinghamshire is the largest producer of sand and gravel in the East Midlands and one of the largest in Great Britain. Sand and gravel is worked from alluvial resources in the Trent and Idle Valleys the Soar Valley and in isolated glacial deposits scattered across the County. The gravel component is normally a quartzitic, high strength material capable of meeting most specifications for concrete. This factor can give Nottinghamshire’s deposits a premium above those found elsewhere which may contain gravels made up of weaker sandstone pebbles. The richest and most extensive deposits occur in the Trent Valley, where yields can exceed 100,000 tonnes per hectare, although 60-80,000 tonnes is more typical.
Local sites
The following localities represent, in part, the geology of this county. Each locality has a grid reference, a brief description of how to get there and a short summary of the geology you are likely to find. All the localities listed are openly accessible.
Select a region
Related articles
