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Warwickshire's Journey Through Time
Plate tectonics is the theory that the Earth's surface is covered by a number of vast,
rigid rocky plates, gradually moving over the liquid, molten rock within the Earth's interior.
This process is driven by heat, generated by radioactivity deep within the Earth.
It is known as continental drift. This theory has helped scientists to solve many
geological puzzles and is now generally accepted.
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Most of Warwickshire's rocks formed as layers of mud and sand in ancient seas, lakes
and river valleys. They contain valuable information on ancient environments and climates,
including many fossil plants and animals. Remarkably, they show that over the last
600 million years, continental drift has carried Warwickshire northwards
across the face of the Earth. |
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550 Million Years Before Present (Cambrian Period) - roughly 60 degrees south of the Equator
A temperate sea covered the region and the Hartshill Sandstone and Stockingford Shale were deposited as layers of sand and mud. Worm-like animals and trilobites lived on the sea-floor.
Reconstruction of a trilobite
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380 Million Years Before Present (Devonian Period) - just south of the Equator
The area was now occupied by a hot, sandy coastal plain. A shallow sea spread inland from time to time, teeming with primitive cockle-like molluscs and other sea-creatures. | |
300 Million Years Before Present (Carboniferous Period) - across the Equator
By this time Central England was enjoying an equatorial climate and was partly covered by a humid, tropical coal swamp. The compacted layers of peat, mud and silt now form the Coal Measures of the Warwickshire Coalfield.
Giant Carboniferous horsetail plant |  |
290-200 million years ago (Permian and Triassic Periods) - heading north
Warwickshire's climate became increasingly hot and dry as Britain drifted further northwards into an arid subtropical belt, 20-30 degrees north of the Equator . The coal swamps were replaced by desert-like environments in which occasional floods deposited the red sandstones of Coventry and Kenilworth.
Brick-red Triassic Mercia Mudstone is widespread in parts of the county and was deposited partly as wind-blown dust, in and around arid salt lakes. | 
Red Triassic Mercia Mudstone, aerial view of M40 motorway
construction near Warwick (photo courtesy of John Ball, Middlemarch Environmental) |
200-170 million years ago (Jurassic Period) - return of the sea
By the dawn of the Jurassic Period, Britain had drifted to a position between about 30 and 40 degress north of the Equator. Marine reptiles, ammonites, sea-urchins and corals thrived in the warm, shallow subtropical sea that now covered the area. | 
Jurassic ichthyosaur |
The present day: 52 degrees north of the Equator
There is a big gap in Warwickshire's geological record, spanning the interval between about 170 million and 500,000 years before the present day. Providing evidence for the last few hundred thousand years, Warwickshire's youngest geological deposits are patches of clay, sand and gravel scattered throughout the county. Their fossils show evidence for a mixture of glacial and warmer conditions, leading to the relatively mild, temperate climate of the present day. | 
Woolly mammoth - ice age Warwickshire inhabitant |
The geology gallery at Warwickshire Museum includes a display
of local rocks and fossils, illustrating Warwickshire's journey through time.
For more information contact the Keeper of Geology:
Telephone 01926 412481
Email museum@warwickshire.gov.uk
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