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Geology - Introduction

Geologic Clock with events and periods

The geological clock: a projection of Earth's 4,5 Ga history on a clock ("MA" = a million years (Megayear) ago; "GA" = a billion years (Gigayear) ago)

The area covered by TVRIGS, that is roughly much of ancient Cleveland and includes the northern parts of the North Yorkshire Moors, has a varied geology with rocks exposed at surface ranging in age from the Upper Carboniferous, 300 million years ago (Ma) to Tertiary, the Cleveland dyke being emplaced 58 Ma. There are extensive superficial deposits of glacial or more recent origin (<2 Ma).

Older rocks are recorded in deep boreholes exploring for gas, oil and evaporates. They are found at surface in areas close to Cleveland such as the Yorkshire Dales, West Durham and Northumberland. Also, the minerals making up the rocks are typically much older. For example, there are the pebbles on our beaches of agates, jasper and tough greywacke that come from the Old Red Sandstone of Scotland that, in turn, come from even older rocks. The oldest rocks and minerals known throughout the world are some 4,000 Ma; an age close to that of the earth itself, 4,600 Ma.

Black-band ironstone

This image shows a 2.1 billion years old rock containing black-banded ironstone, which has a weight of about 8.5 tons. The approximately two meter high, three meter wide, and one meter thick block of stone was found in North America and belongs to the National Museum of Mineralogy and Geology in Dresden, Germany.

Many of us will be familiar with television programmes such as those by Sir David Attenborough and Professor Ian Stewart describing the changing planet earth with reference to plate tectonics, subduction, mantle plumes, ancient continents and oceans, etc. and the affect crustal changes have had on the evolution of life. We need not worry too much about these here. By the Carboniferous, the continental crust (the first 50 miles or so below the surface of the earth), underlying Northern England had become stabilised with fault-bounded blocks and basins. Eventually, around 250 Ma, our area, indeed most of the British Isles, was part of the Pangaea super-continent, relatively stable within itself, but subject to external influences that did give rise to worldwide changes in sea level, to local crustal thinning and extension and to climatic changes.

Lower Middle Jurassic Port

Cliffs comprising rocks of Lower and Middle Jurassic age on the coast. Looking east at Port Mulgrave.

The crustal thinning and consequent sagging and extension gave rise to the Cleveland Basin, itself an extension of the North Sea trough. As the basin subsided it was gradually infilled through much of Late Permian, Triassic, Jurassic, Cretaceous and even early Tertiary times (250 to30 Ma). However, there was then a major change from subsidence and sedimentation to uplift and erosion, referred to by geologists as a ‘basin inversion’. It is reckoned that at least 1,000 m of strata have been removed, including the Chalk that is now found in the Yorkshire Wolds. The affects of this erosion have given rise to the present physiography that is in itself part of the geological history. It includes the development of the present river system and the peneplanation of the landscape to form broad features such as the eastern slopes of the Pennine Hills and the Tees Valley.

Quelccaya Glacier

Glaciated landscape.

The landscape was modified by the repetitive Quaternary glaciations, with both extensive erosion and deposition of superficial deposits. The last glaciation and subsequent post-glacial times dating from the present to around 15,000 years ago gave rise to further interesting erosional and depositional features such as overflow channels and submerged forests.

Redcar Steelworks at Night

Redcar Blast Furnace at night

We must not forget the anthropogene; the geology of modern times affected by human activity. For example, there are the results of mining and land reclamation.

Explore the different areas of Geology:

Rocks and Periods

Upper Carboniferous


Modern Chemicals
Other Industries

If you have a question about your local geology, or a rock, mineral or fossil you’d like identified then please visit our Contact Us page and we will do our best to help.


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View north from Skelton Hissing Scar Huntcliff-at-Saltburn Kilton Mine from Little Moorsholm Cleveland-Yorkshire Coast near Staithes Duck Bridge, Danby View east from Boulby Quarries Kilton Mine Spoil Heap Loftus Alum Quarry Lumpsey Ironstone Mine ca1920 Roseberry Topping Skinningrove Blast Furnaces Spa Wood Ironstone Mine Marske Hall North Skelton Ironstone Mine Redcar Submerged Forest View north-east from Loftus Quarries

Explore TVRIGS



One fundamental aspect of work done by Tees Valley RIGS Group involves compiling a Catalogue of Geodiversity which covers our area of operation - Geodiversity being the variety of rocks, fossils and unconsolidated deposits making up the district.



The area covered by TVRIGS, that is roughly much of ancient Cleveland and includes the northern parts of the North Yorkshire Moors, has a varied geology with rocks exposed at surface ranging in age from the Upper Carboniferous, ...



Part of the fun of geology is making visits to sites of interest, where the geology, industrial archaeology, or both can be seen in-the-flesh as it were. To help people get the most out of such visits TVRIGS has compiled a number of outings (geotrails) ...

marske quarry


As a body of volunteers Tees Valley RIGS Group receives no direct funding but can bid for small amounts from funding bodies such as HLF (Heritage Lottery Fund), ALSF (Aggregates Levy Sustainability Fund), and so on when such monies are ...