1. Site Description
2. Geology
3. Access
4. General Assessment:
5. Associated Sites
6. Safety Information
7. Supplementary Information
8. Geology
9. Industrial History and Archaeology
10. Literature References
11. Maps & Plans
12. Surveyors

Site Description

Grid Reference: NZ 755 195
BGS Sheet: 34
OS Sheet: 94
Forwarded as RIGS: 30/09/2003

Site Status: SSSI (RIGS Site Ref: RC5, Site No. 54 [ * Under Review * ]). Open access.

Please Note: The quarry is situated on private land, however spectacular views can be found by walking along the Cleveland Way and other adjacent public footpaths.

Description of Geodiversity: Extensive former alum quarry of great geological, scientific, historical and industrial archaeological interest. The Cleveland Way passes around the southern edge and along the top of the quarry back-wall that rises to over 200m O.D. The coastal scenery is impressive.

View of Boulby Quarries (foreground) showing Cowbar Nab near Staithes (background). Taken from the Cleveland Way above Sallow Tree Plain.

Geology

The quarries form the upper part of a virtually complete Jurassic succession ranging from the Lower Jurassic Redcar Mudstone Formation on the foreshore to the Middle Jurassic Saltwick Formation at the top. The quarried beds of interest to the alum industry constitute principally the Alum Shale Member of the Whitby Mudstone Formation. The beds exposed in the quarries are:

• Saltwick Formation: This forms the southern back-wall of the quarry, some 600m in length and up to 30m in height. It is formed predominantly of river channel sandstones. These exposures are difficult to reach and best examined more closely within the numerous fallen blocks.
• Dogger Formation: This Formation is about 1m thick and consists mainly of siliceous ironstone. It is sometimes absent as a result of washouts, and is now poorly exposed.
• Alum Shale Member: There are good exposures of the lower beds of shale (Whitby Mudstone Formation) which form the quarry floor especially at the western end.
• Reasons for SSI Status: Although the SSSI is named Boulby it actually includes both Boulby and Loftus Quarries. Two significant features, the murchisonae shale facies of the Dogger Formation and the finding of pterosaur remains in the Alum Shale, are at Loftus Quarries but it is likely that other reptilian remains were also found at Boulby.

Geomorphology: Several past and potential landslips and rockfalls can be seen and, in contrast, examples of slow, gradual sub-aerial cliff erosion.

Historical geology: This is the site of 19^th century measured sections by Rev. George Young, John Phillips, Lewis Hunton and others.

Industrial Archaeology:

• The quarry was a major alum site with at least two stages of development – mid-17^th to late-18^th century and late-18^th to late-19^th centuries. Across the site can be found the remains of calcining places, steeping pits, buildings, reservoirs, liquor conduits, etc. The stone revetments at the western end are most impressive.
• There are small ironstone trials of the Top Seam (Dogger Formation).
• The quarry is underlain by the extensive underground workings of the Main Seam (Cleveland Ironstone Formation) that are exposed along the sea cliff face.

Access

Access map for Boulby Quarries showing extent of SSSI and suggested parking.
(Click on map to enlage)

The easiest access is from the east along the Cleveland Way. A minor road off the A174 affords suitable parking.

General Assessment:

The quarry is an excellent venue for demonstrating Lower and Middle Jurassic geology, recent geomorphology, historical geology and industrial archaeology (alum and ironstone workings). The high cliffs require care.

Associated Sites

Boulby Sea Cliffs and Foreshore (North Yorkshire Heritage Coast, RC5, other reference 80.);
Loftus Alum Quarries (SSSI, other reference no. 53).

Safety Information

PLEASE NOTE: Due to the presence of high unfenced cliff faces we suggest that this site is not suitable for visits by unsupervised children. Please remain well away from the cliff edge and ensure any dogs are kept on a lead. Because of their unstable nature these cliffs must not, under any circumstances, be climbed.

Please follow the Country Code. Do not light fires. Take any litter home.

In situ fossils must not be collected, but their positions noted and details passed on to TVRIGS, a local museum or other similar body. Scattered fossils already weathered from the rock may be collected freely.

Supplementary Information

Geology

Structure: The succession is shown in the accompany section. The beds dip about 3° to the south.

Section through the cliff and quarry demonstrating the gentle dip of the beds.

Saltwick Formation (deltaic/alluvial): This forms the impressive back-wall of the quarry and consists principally of massive lenses of river channel sandstone. It is generally difficult to reach owing to fallen rock. Blocks, some extremely large, can be readily examined showing sedimentary structures such as cross-bedding and the imprints of plant remains.

Dogger Formation (marine incursion): This is about 1m in thickness and consists mainly of siliceous ooidal ironstone. However, at the eastern end it is described as ooidal siderite mudstone overlain by dark mudstone with similar mudstone nodules, as a clear result of lateral transition (Rastall and Hemingway, 1940). It is now poorly exposed. Blocks of ironstone can be examined that form a roughly laid wall by an old trial adit.

Alum Shale Member (marine): Some 10m of beds are exposed at various sub-quarry levels especially at the western (Sallow Tree Plain) end of the workings around the stone revetments. They consist of weathered, friable, grey, iron-stained, poorly bedded, flaky shale with vertically disposed jointing on the small scale. Fossils, chiefly poorly preserved belemnites, are uncommon but when seen may be present in clusters. Small acicular crystals of iron-stained gypsum are common. Occasional beds of lighter grey, calcareous, sometimes septarian, nodules can be found but, so far, Howarth’s (1962) detailed lithostratigraphic succession has not been elucidated. It is likely that the beds exposed belong to the lower part of the Alum Shale Member (the Hard Shale sub-unit) or even the upper part of the Mulgrave Shale Member.

Revetment walls at the west end of the site with Cowbar Nab in the background.

Geomorphology: The back-wall of the quarry has been subject to rock falls and there is now much debris at its foot. At the top, on the Cleveland Way there are open fissures with the cliffs being in a poor state. At quarry level on the seawards side there have been several landslips reported during and since the period of working that have carried away parts of the alum works and particularly the former tracks down to the shore. Elsewhere, such as for example at the Sallow Tree Plain (western end) steeping pits the cliff erosion has been limited. The ground between the Boulby and adjacent Loftus Alum Quarries illustrates how the original cliff profile looked.

Historical geology: Boulby Quarry and the sea cliffs beneath (making use of the tracks down to the shore) are where several 19^th century and, more recently, geologists such as Chowns made measured sections. That by Lewis Hunton (1836) is the most notable as he independently recognized the importance of collecting fossils in-situ, and relating the fossils found to the beds in which they occur bolstering the emerging concept of biostratigraphy.

View of Boulby Quarry and cliff as seen from Bias Scar toward Staithes.

Industrial History and Archaeology

Alum: The alum works was started in the 1650s at the eastern (Rockhole Hill) end of the quarry, redeveloped at the western (Sallow Tree Plain) end in 1784, and eventually closed in 1871. The alum house was about 0.5km to the south-east and, as well as tracks, there was a shaft and tunnel here connecting the house to the dock at Hole Wyke (see Boulby Sea Cliffs and Foreshore). The history and industrial archaeology of the alum works has received much attention in recent years (see references).

Ironstone: The Main Seam of the Cleveland Ironstone Formation has been worked extensively under the quarries from:

• (a) Boulby Mine, miners’ drift entrance at NZ 754 191, and
• (b) Grinkle Mine drift at NZ 762 177.

Boulby Ironstone Mine main haulage drift is now under the surface buildings of Cleveland Potash Mine, and the fan shaft is near the railway at NZ 757 179. The Main Seam typically consisted of a Top Block ~1m, Shale 0.3m and Bottom Block 0.7m. Waste was tipped in to the sea from a drift exit on the sea cliff at NZ 762 190. There are two trials of the Top Seam ironstone of the Dogger Formation, one within the quarries and one a short distance to the east (at NZ 758 190).

Current mining: Cleveland Potash Mine (at NZ 762 184) is of major importance to the local and national economies. Production started in 1973 and is of the order 1 million tonnes per year of potash (sylvinite) as well as rock salt (halite). The workings extend over a wide area that includes Boulby Quarry at a depth of around 1100m below sea level.

Literature References

Maps & Plans

Geological Survey Yorkshire Sheet IX SW, Rockcliff, scale 6 inches to 1 mile, 1878 (Ordnance Survey 1856).
Notes on the Lower Lias, Main Seam and Dogger. Shows 12 Steeping pits at Sallow Tree with cisterns, various buildings and reservoirs. Rockcliff (Pithill) building shown with various paths and reservoirs.

Geological Survey Yorkshire Sheet IXX NW, Boulby, Runswick & Kettleness, scale 6 inches to 1 mile, 1899 (Ordnance Survey 1856).
Shows outline plan of the alum house.

Ironstone Abandonment Plans (at Teesside Archives)

Boulby (1 plan), abandoned 2/7/1934. Ref. 11232
Grinkle (4 plans), abandoned 21/6/1934. Ref. 11261

Barrow, G. 1888. The Geology of North Cleveland. Mem. Geol. Survey, H.M.S.O., London, 101p.
Official memoir. Page. 9 shows the Main Seam ironstone section made on ‘the old road now slipped away’. Pages 42 and 43 show Dogger sections.

Chapman, S. K. 1975. Excavations at the Boulby Alum Works. Cleveland Industrial Archaeology Soc., 2, 23-47.
One of the first industrial archaeological accounts of an alum works.

Chapman, S. 2005. Boulby Alum Works Visit. C.I.A.S Newsletter No. 88, 11-17.
Industrial archaeological excursion guide.

Chapman, K. 2002. Boulby Alum Works. Chapter 6 in ‘Steeped in History’ (ed. Miller, I.), North Yorks Moors National Park Authority, 61-74.
A revised account of the 1975 work with additions and maps by English Heritage.

Fox-Strangways, C. 1892 The Jurassic Rocks of Britain, Volume 1. Yorkshire. Geol. Survey, H.M.S.O., London, 551p.
Similar to Barrow, 1888.

Goldring, D. 2001. Along the Scar. Peter Tuffs, Guisborough, 145p.
See pages 59 to 65.

Goldring, D. 2007. Louis Hunton and Loftus Alum Works. Cleveland Industrial Heritage No. 21, 9-15.
Includes a copy of Hunton’s famous section emphasising points of industrial interest.

Hunton, L. 1836. Remarks on a Section of the Upper Lias and Marlstone of Yorkshire, etc. Trans. Geol. Soc. London, 5, 215-220.
This is Hunton’s classic paper and includes his section at Boulby, undoubtedly the best by the early 19th Century geologists.

Jecock, M. 2009. A Fading Memory: The North Yorkshire coastal alum industry in the light of a recent analytical field survey by English Heritage. Industrial Archaeology Review, 31, 54-73.
General review of the alum industry, including several pictures of Boulby.

Marley, J. 1857. Cleveland Ironstone, etc. North of England IME Trans., 165-219.
Early, 19th Century ironstone working.

Miller, I. 2002. Steeped in History North York Moors NPA.

Osbourne, R. 1998. The Floating Egg Pimlico.

Phillips, J. 1829. Illustrations of the geology of Yorkshire, etc. Part 1 The Yorkshire coast. Private publication, York, 192p. (2nd Edition 1835 and 3rd Edition 1875, edit R. Etheridge).
Classic account. Section no. 9 shows some detail at Boulby.

Quinn, K. 2009. Boulby Alum: The works diary of George Dodds, (1772-1788). Cleveland Industrial Archaeology Society Research Report No. 9, 76p.
A detailed, primary historical account of operations at Boulby.

Rastall, R. H. & Hemingway, J. E. 1940. The Yorkshire Dogger, 1. The Coastal Region. Geol. Mag., 77, 177-197 & 257-275.
This is the only detailed description of the Dogger Formation for the Cleveland area. Pages 191 and 192 refer to Boulby sections and pages 263 and 264 to the petrography.

Tate, R. and Blake, J. F. 1876. The Yorkshire Lias. John Van Voorst, London, 475p.
Pages 132 and 133 show the ironstone section as seen on the path to the shore. Pages 170 and 175 detail the section in part of the Whitby Mudstone Formation.

Torrens, H. S. and Getty, T. A. 1984. Louis Hunton (1814-1838). English Pioneer in Ammonite Biostratigraphy. Earth Sciences History, 3, 58-68.
A biography stressing the scientific importance of Louis Hunton.

Tuffs, P. 1996. Catalogue of Cleveland Ironstone Mines. Peter Tuffs, Guisborough, 56p.
General details of the mines.

Young, G. and Bird, J. 1822. A Geological Survey of the Yorkshire Coast. Clark, Whitby, 332p. (2nd edition 1828).
The classic measured section at Boulby is on page 134 in the 2nd Edition with the Whitby Mudstone Formation divided into 3 subdivisions.

Surveyors

Denis Goldring 2011

©2011 Tees Valley RIGS Group.

This page provides a glossary of geological terms to be found on the TVRIGS website and elsewhere. It is an evolving document and will grow as the site expands.

L

M

P

Q

R

S

«Glossary(F-K) Glossary(T-Z)»

PLEASE NOTE: TVRIGS Group cannot be held responsible for the content of external sites.

Sylvinite - This specimen from Russia.
Image courtesy of shakko.

These rocks form an economically important group of minerals. Sylvinite (a mixture of potassium chloride, sodium chloride and clay minerals) and halite (rock salt) are extracted by Cleveland Potash Ltd. from their mine at Boulby, near Staithes. The sylvinite lies within Permian strata over a kilometer below the surface. It is a little under 290 million years old and was laid down when a shallow ancient sea, dubbed the Zechstein – and which occupied an area between Northern England, through the North Sea Basin, to Poland – underwent several cycles of evaporation and transgression. Sea water comprises ~3.5% dissolved salts of which the bulk is sodium chloride or common salt. Evaporation yields successively limestone, anhydrite (calcium sulphate), halite and finally potassium and magnesium salts. Anhydrite was formerly mined and processed at Billingham on Teesside.

Cleveland Potash Mine, Boulby, Cleveland. UK

Evaporite deposits can flow under pressure producing salt-domes which disturb the strata through which the pass and internally exhibit complex folding. They also retain heat and may be a target for future geothermal energy projects.

Anhydrite - Once mined at Billingham on Teesside, UK.
Credit: Commons Wikimedia

Locally, there are many hundreds of metres of Permian evaporite deposits, both sylvite and rock salt (halite), beneath Teesside and North Yorkshire which were deposited around 260 million years ago when the ancient Zechstein Sea became land-locked and evaporated. Middlesbrough formerly fostered a thriving salt industry, and sylvinite (for use as fertiliser) and halite (essential for keeping roads ice-free in winter) are still mined locally at Cleveland Potash’s mine near Boulby which descends over a kilometre beneath the surface to reach the Permian strata.

Sylvite crystals

Shown below is a representation of the rocks underlying the Tees Valley and Darlington districts in Northeast England. The diagram depicts the relative thickness of the different systems. Absolute ages are given alongside. Click on the different areas to view more details about a particular time period.

Geological column showing the relative thickness and absolute ages of rocks underlying the Tees Valley and Darlington.

The place for you to find out more about the geology and industrial heritage of Redcar & Cleveland, Middlesbrough,
Stockton, Hartlepool and Darlington.

Alum, Alchemy and Ammonites Page
 
Future Events Page
 
Past Events Page

Why not check out our new site description pages and geo-trails

                        Boulby – Cowbar                           Hummersea
                        Loftus Quarries                              Boulby Quarry

Latest News

RIGS News

• Tuesday 8th November 2011: November’s Rock of the Month offering can now be viewed by clicking here…

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• Thursday 13th October 2011: The RIGS Group’s recently published Geodiversity Action Plan has been recognised and used as a case study by Geoconservation UK. More details can be seen here and by clicking on the navigation bar at the top of this page.

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• Wednesday 12th October 2011: Why not view Tees Valley Wildlife Trust’s Alum, Alchemy & Ammonites pages.

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• Wednesday 1st June 2011: Our latest Rock of the Month article is now online. We would like to thank RIGS Group member Scott Bradley for providing the article.

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• The group’s expansion into the Darlington district is approaching the end of its first phase. A number of sites have been identified and five summarily surveyed.

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Announcements

• For details concerning the next RIGS meeting please contact the RIGS Group by e-mail.

Ramblers walking with the RIGS Group descend Boulby Bank after visiting cliff-side alum quarries near Staithes.

TVRIGS are always keen to recruit new members. So if you have an interest in the region’s geology, would like to find out more about the Tees Valley’s industrial heritage, or simply wonder what all of the fuss is about, then why not join us, it’s free – and we have only the very best biscuits at our meetings…

Unless otherwise stated, all images on this site ©2010 & ©2011 TVRIGS Group.

1. Summary
2. Lower Permian
3. Upper Permian

Summary

Column showing the Permian rocks of the Tees Valley.

The addition of a Permian System of rocks to the history of the Earth was proposed in 1841 by eminent geologist Roderick Impey Murchison (1792-1871) after performing geological surveys in the Perm region of Russia where beds of this age are well represented.

Earth movements during the preceding Carboniferous Period gradually raised the land’s surface across much of the UK in an episode of mountain-building dubbed the Hercynian Orogeny. This event raised the Harz Mountains in Germany and, further north, the Mercia Highlands which once extended between Devon and the Wash. Former areas of well-vegetated tropical delta-marsh, within which the commercially important Coal Measures developed were buried as a hot arid desert advanced across the area. It was under these conditions that rocks of Permian age began to be deposited within the Tees Valley between 299 and 251 million years ago.

Lower Permian

The lowest, and hence oldest, beds in the Permian succession locally are a mixture of dune-bedded sandstones and coarse breccias that accumulated upon the undulating Carboniferous land surface. Occasional wind-polished rocks, known as ventifacts, can be found amongst the deposits, which are comparable to those accumulating in the Sahara today. A lack of fossils perhaps highlights the harsh conditions which existed during the sediment’s emplacement.

Upper Permian

Further mountain-building (orogenic) activity to the south caused the land surface to buckle and fold forming a broad inland basin. To the north and east, a communication developed with the Zechstein Sea, which rapidly transgressed across North East England to occupy the former desert plain. Further subsidence meant that this new arm of the sea reached depths approaching 200 metres further east, though locally the area was close to a shoreline. This marginal environment was colonised by coral reefs, stromatolites, and a rich fauna of other marine creatures. Their remains combined with a restricted input of fine sediment blown from the nearby desert to produce beds of limestone. This reef environment was to be short-lived however, as a new period of uplift caused the English Zechstein to become cut off from the main water body. Conditions rapidly deteriorated in the isolated sea as evaporation of its diminishing waters concentrated their mineral content. During the final phases a sabkha zone developed, comprising hypersaline lagoons, pools of hot mud, and glittering beds of evaporites stretching across the desert.

Permian Magnesian Limestone foreshore as seen at Hartlepool Headland.

The Upper Permian is typified by five such incursions, followed by evaporation, of the English Zechstein (cycles EZ1-5) with the later episodes never attaining great depth. The resulting strata comprise various limestones and mudstones with intervening beds of evaporites. The latter became important commercially during the late 1800s when salt (halite)extraction on Teesside constituted the beginnings of today’s modern chemical industry. Later, anhydrite was mined in great quantities around Billingham, and potash (sylvinite) along with rock salt is still extracted from deep mines, over a kilometre below the surface, at Boulby Mine, near Staithes.

Fossil content within the Permian succession diminishes the higher up one looks, and this is not simply an effect of the harsh conditions locally, but is reflected within the fossil record worldwide. During what has become known as the Permian Mass Extinction, some 95% of all marine species died out never to return, with a lesser, though not insubstantial, number of terrestrial creatures joining them. The event is billed by geologists as the greatest extinction so far suffered by life on Earth. Life’s tenacity, however, never fails to amaze, and the survivors of this catastrophe would, over the next 40 million years or so, adapt and radiate into niches vacated by many of their predecessors to produce a whole new era of life on Earth – the Mesozoic Era.

« Upper Carboniferous                         Triassic »

©2011 Tees Valley RIGS Group.

The the addition of the letter ‘o’ to spell geo was simply to make the word sound better: “gelogy” would sound awful!

It is the rocks of the Tees Valley that have brought industry and money into the area. Some of the rocks to be found here are more important than others. But all of them have in some way played a part in building the Tees Valley.

To find out more about any of the rocks in the Tees Valley select a geological period from the list below. The geological periods are given in chronological order (order of time) with the oldest period at the bottom of the list.

• Quaternary
• Tertiary
• Jurassic
• Triassic
• Permian
• Carboniferous

Click here for a detailed geological timescale for rocks in the Tees Valley.

1. Site Description
2. Site Map
3. Site Assessment
4. Surveyors

Grid Reference NZ 471 371
BGS Sheet 27
OS Sheet 93
Forwarded as RIGS 30/09/2003

Site Description

Site Status SNCI
Description of Geodiversity Deep gorge environment revealing exposures of Magnesian limestone. The gorge forms steep sides consisting of face of Magnesian limestone in a fluvial environment. Glacial erratics can be found in the stream bed.
Literature References The Geology of the Country Between Durham and West Hartlepool – Denis Smith 1967

Site Map

Site Assessment

Surveyors

Andrew Carter, John Waring

1. Site Description
2. Site Map
3. Site Assessment
4. Surveyors

Grid Reference NZ 524 344
BGS Sheet 27
OS Sheet 93
Forwarded as RIGS 30/09/2003

Site Description

Site Status SNCI
Description of Geodiversity Wave washed platform of Magnesian limestone. The exposure reveals examples of stack an pillar coastal features.
Literature References The Geology of the Country Between Durham and West Hartlepool – Denis Smith 1967

Site Map

Site Assessment

Surveyors

Andrew Carter