• Local GAPs

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Abberley Hall East (Valley of the Rocks)

Exposed Units: Much Wenlock Limestone Formation

Conservation Status: Local Geological Site

Access: Private

Abberley Hall East is a long, linear quarry, set in woodland to the south east of the Abberley Hall School. Quarrying is thought to have ended in the early 19th century and was marketed as the ‘Valley of the Rocks’ when the estate was sold in 1836.

The site is a long, linear quarry composed of the Wenlock Limestone Formation that is approximately 500m long and 40m wide. The best exposed faces are on the western side of the quarry, which are approximately 30m high. They comprise overturned beds of nodular limestone that are oriented near vertical in places and form part of a limb of a local fold structure. Smaller faces can be seen high up on the eastern side of the quarry, with the best of these exposures at the southern entrance. The limestone in the western face is a greenish grey colour and has a silty, nodular fabric. The nodules when split are hard, finely crystalline and grey in colour. The beds in the eastern face are smaller and reveal a highly fossiliferous surface containing some brachiopods and many crinoidal columns, some of which reach up to 2cm in diameter. In the centre of the west face there is a vertical fault filled with the mineral calcite.  This bisects the face and extends to the top of the exposure.

This site is part of the Community Earth Heritage Champions Project.

 

Terminology

Fold – A curved or angular shape of an originally planar geological surface

Fold limb – The part of the fold between the hinges (hinges: the location of greatest curvature of a folded surface)

Fault – A line of weakness within the Earth’s crust along which movement and displacement occurs

Photos

Nodular limestones of the Much Wenlock Limestone Formation at Abberley Hall East quarry.

References

British Geological Society (1960), Geology of the country around Droitwich. Sheet 182

(England and Wales), 1:50,000.

Mitchell, G.H. et al. 1962, Geology of the country around Droitwich, Abberley and Kidderminster. British Geological Survey Memoir.

Mykura, W., 1952, ‘The Age of Malvern Folding’, Geological Magazine, vol. 88, 6, pp. 386-392.

Phillips, J., 1848, The Malvern Hills compared with the Palaeozoic districts of Abberley, Memoirs of the Geological Survey of Great Britain and of the Museum of Practical Geology London. Vol. II, Part 1.

Tucker, M.E., 1991, Sedimentology Petrology (2nd Edition). Blackwell Scientific Publications.

Woodcock, N, and Strachan, R., 2000, Geological History of Britain and Ireland, Blackwell Publishing.

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Beckford Gravel Pit

Exposed Units: Post-Anglian Deposits (Wasperton Member)

Conservation Status: Site of Special Scientific Interest

The locality contains a significant cliff exposing interbedded sands and gravels that were deposited by and around the ancient River Avon. Gravel beds are 10-30 cm in thickness and sand beds are generally thinner but also form wedges that may be up to 20 cm thick. The gravel clasts have been derived from material eroded by the river and are dominantly limestone, although occasional grains of a dark, nodular rock of uncertain affinity are present. Sand grains are generally very rounded and spherical, indicating that the sand may also have been wind-blown before it formed part of the Wasperton Member.

The transitions from gravel to sand layers are sharp, indicating erosive surfaces, or representing sudden changes in the carrying capacity of the river; a fast-flowing, more powerful river (for example, a river in flood), is able to transport larger particles than a sluggish river. In the lower part of the section, there are possible slumping, buckling and frost heave features, which indicate deposition in a cold climate that is significantly influenced by repeated freeze-thaw events. In the upper part of the section, the gravel beds become thinner. In the topmost metre of the section, very large clasts indicate periods of much higher energy transport, possibly as a result of the conditions at the end of the Last Ice Age (Devensian).

The characteristics of the Wasperton Member at this locality indicate that the overall climate at the time of its deposition was cold (but not covered in ice) and arid, suggested by the presence of freeze-thaw structures and wind-blown sand respectively. The sand is not local, with the nearest possible source being the Triassic sandstones of northwest Worcestershire. The limestone clasts which make up the gravels are likely to have been sourced from Bredon Hill, where there are extensive outcrops of Jurassic limestone.

Terminology

Clast – A rock fragment that has been incorporated into a rock from another rock.

Carrying capacity – The ability of a river to transport a sediment load.

Freeze-thaw structures – Weathering features in rocks caused by the repeated freezing and thawing of water contained in fractures and pore spaces.

Deglaciation – The process of glacier retreat and melting at the end of a glacial period. Opp. glaciation.

Photos

General view of the cliff face exposure at Beckford Gravel Pit showing horizontally-layered sand and gravel beds in the Post-Anglian age Wasperton Member.

General view of the cliff face exposure at Beckford Gravel Pit showing horizontally-layered sand and gravel beds in the Post-Anglian age Wasperton Member.

Discontinuous bands ofcoarse gravel surrounded by finer sand.

Very coarse, angular clast being weathered out of the cliff face. The finer-grained sand and gravel is more easily eroded by wind and weather, which slowly picks out the larger grains.

Photograph showing the variable and repetitive nature of river deposits. To the right of the photo is a wedge of very coarse gravel that pinches out towards the left of the image. This is overlain by a wedge of sand that pinches out towards the right of the photo, which has coarse-grained material at the bottom but becomes finer moving up. These are both overlain by continuous bands of gravel and sand at the top of the image.

Slumping in a sand wedge of the Wasperton member. Sediment deposition on a slope in a river channel caused the slope to become unstable. A lens of material slumped down onto underlying sandy material. The direction of slumping is moving towards the camera. The slump structure is overlain by a band of gravel that would have scraped away the top layers of the slump when it was deposited, so forming an erosive boundary.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

Briggs, D.J., Coope, J.R. and Gilbertson, D.D., 1975, ‘Late Pleistocene terrace deposits at Beckford, Worcestershire, England’, Geological Journal, 10, pp. 1-17.

Brown, A.G., 1983, ‘Floodplain deposits and accelerated sedimentation in the lower Severn Basin Article’. In: Gregory, K.J. (eds.), Background to palaeohydrology, Wiley, Chichester, pp. 375-397.

Dawson, M.R., 1986, ‘Late Devensian fluvial environments of the Lower Severn Basin, UK’, PhD Thesis, University of Leicester, Leicester.

Gregory, K.J., 1997, ‘Beckford, Hereford & Worcester’. In: Gregory, K.J. (eds.), Fluvial geomorphology of Great Britain, Geological Conservation Review Series, 13 JNCC, Peterborough, pp. 347.

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Broad Down Quarry

Exposed Units: Warren House Formation

Alternative site names: Reservoir Quarry

The Warren House Formation crops out in the Malvern Hills from east of Herefordshire Beacon down to Hangman’s Hill in the south. At Broad Down Quarry, excavations revealed a sequence of ignimbrites and tuffs with an easterly dip ranging from 45°-~90°. It exposes unstructured, pink and blue-coloured crystal-lithic tuffs with a uniform composition. A dolerite dyke, somewhat sheared, is also found in the quarry, and the mineral epidote is fairly prevalent.

In the northwest part of the quarry, ignimbrite flows of Warren House Volcanics extend from the northern entrance around the northern, western and southern walls.  The ignimbrites are pink in colour due to hematite staining.    The freshest rocks are exposed in this part of the quarry are felsic to rhyolitic fragmental tuffs with rounded quartz xenocrysts. The flows are massive and fairly uniform.

In the southeast part of the quarry, dolerite predominates over ignimbrite.  In places, large blocky xenoliths of ignimbrite are entrained in the dolerite intrusions, but a lack of complete exposure prevents a definite conclusion from being drawn. The dolerite itself is fine-medium grained pale pink to yellow-brown felsic tuff. This is overlain by very fine-grained, greyish purple tuff of more intermediate composition, indicating the presence of compositional and grain size banding. The junction between these lithologies dips about 20° SE. The units are cut by thin epidote veins and East-dipping shear planes of inferred Variscan origin, which led to intense tectonisation in the volcanics at this site.

Terminology

Ignimbrite – A destructive flow of volcanic ash, gases and rock particles that is erupted violently from a volcano.

Crystal-lithic tuff – A volcanic ash (tuff) containing large crystals from the magma as well as rock fragments.

Xenocryst – Crystals incorporated into the magma from surrounding rocks

Variscan – Descriptive term for rocks/structures that formed during the Variscan orogeny, a period of mountain building in central Europe, North America and southern England that took place between 380 and 280 million years ago.

Photos

Southern face of Broad Down Quarry, showing the lichen-covered, massive (unstructured) ignimbrite.

Boundary between the pink-brown felsic to rhyolitic (acid) ignimbrite (left) and the blue-grey intermediate ignimbrite (right).

Dolerite dyke intruding intermediate ignimbrite at Broad Down Quarry. The dyke is oriented near-vertical in the central part of the photograph.

 

 

 

 

 

 

 

 

 

References

Barclay, W.J., Ambrose, K., Chadwick, R.A., and Pharaoh, T.C., 1997, ‘Geology of the country around Worcester’, Memoirs of the British Geological Survey, British Geological Survey, London.

Bullard, D.W., 1989, Malvern Hills – A student’s guide to the geology of the Malverns, Nature Conservancy Council, Peterborough.

Carney, J.N., Horak, J.M., Pharaoh, T.C., Gibbons, W., Wilson, D., Barclay, W.J., Bevins, R.E., Cope, J.C.W. & Ford, T.D., 2000, Precambrian Rocks of England and Wales, vol. 20, Joint Nature Conservation Committee, Peterborough.

Penn, J.S.W., and French, J., 1971, The Malvern Hills, Geologists’ Association Guides, vol. 4, Geologists’ Association

Platt, J.I., 1933 ‘The petrology of the Warren House series’, Geological Magazine, vol. 70, pp. 423-429.

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Broadway Quarry

Exposed Units: Salperton Limestone, Aston Limestone, Birdlip Limestone

Conservation Status: Local Geological Site

Broadway Quarry is located within the Cotswolds Area of Outstanding Natural Beauty and lies adjacent to the Cotswold Way, one of the National Trail walking routes. The Quarry has been in operation for some 120 years and has extracted limestone for both aggregate and building stone. It provides an excellent natural environment resource and for these reasons the site is designated as both a Local Geological Site (LGS) and Special Wildlife Site (SWS).

Broadway Quarry has exploited Jurassic limestones from the Birdlip, Aston and Salperton Limestone Formations of the Inferior Oolite Group. The existing quarry can be divided roughly in half by a fault that runs WNW-ESE across the site. Rocks on the south side of the fault are displaced downwards by 22m to 25m and the Aston Limestone is folded into a small syncline in the east face of the Quarry. The fold and fault run parallel to each other, leading to the suggestion that the fold formed as a result of flexure in the crust at the time of fault movement.

The lower part of the Notgrove Member (of the Aston Limestone Formation) is seen at the top of the face at the back of the quarry, and overlies the full thicknesses of the Gryphite Grit Member. The Aston Limestone Formation and the Harford, Scottsquar and Cleeve Cloud Members of the Birdlip Limestone Formation are also exposed south of the fault that bisects the quarry. On the north side of the fault, only the Cleeve Cloud Member is seen, the Clypeus Grit Member of the Salperton Limestone Formation and the Notgrove and Gryphite Grit Members are exposed in a wedge of land where the fault splits into two arms.

The units in the quarry are present as a series of fossiliferous ooidal limestone with occasional interbeds of sandstone and shale. Of notable mention is the Harford Member, as Broadway Quarry exposes one of the beset sections of the unit. Here, the Harford Member comprises a ~8m section of sandstones and limestones, topped by a series of mudstones. The top unit is some 3.3m thick and contains large black masses of lignite, giving it a distinctive dark grey colour. As a consequence it stands out visually from the light coloured limestones and sandstones around it. The nature of the Harford Member indicates a change in environment at the time of deposition. In contrast to the shallow marine limestone of the other units, the presence of lignite indicates more terrestrial conditions and an environment restricted in oxygen – possibly a freshwater lagoon. The sands lying directly below the mudstone are unconsolidated, suggesting a deposition on a beach or nearshore environment.

Terminology

Fossiliferous – fossil-bearing

Ooidal limestone – a limestone that is made up of small, pellets of limestone called ooids. Ooids are formed in clear, shallow marine shoals when a small nucleus is rolled around by waves and currents in carbonate-rich sea water. They increase in size by ‘snowballing’ and are not formed by biological activity.

Lignite – also known as ‘brown coal’. This is a type of immature coal formed from the remains of plant matter deposited in a coastal/deltaic/swampy environment.

 

Photos

General view of Boradway Quarry, showing cream-coloured Jurassic oolitic limestone and the dark-grey Harford Member.

General view of the quarry floor with piles of aggregate in the fore- and mid-ground.

Exposed face showing well-bedded limestone and shales. The Harford member is particularly well-defined.

Rock being crushed for aggregate.

Folded structures in limestone beds have been exposed by quarrying.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

Understanding the Historic Environment of Aggregate Landscapes, 2007, Extract from ALSF Annual Report, pp.3.

Barron, A.J.M., 1999, Report on Broadway Quarry, Worcestershire, British Geological Survey, Keyworth.

Barron, A.J.M., 2000, ‘Broadway Quarry, Worcestershire: An enlarged section in the Inferior Oolite Group’, Proceedings of the Cotteswold Naturalists Field Club, pp.309-321.

Broadway Quarry Wooded Spur application, 1996, D.K. Symes Associates, Technical report.

Jones, V.E., 1991, The County of Hereford and Worcester draft minerals local plan, Herefordshire & Worcestershire County Council, Worcestershire, pp. 59.

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Brockhill Court Quarry

Exposed Units: Brockhill Dyke, Raglan Mudstone

Conservation Status: Local Geological Site

The Brockhill Dyke is a type of intrusive igneous rock with a dolerite/teschenite chemistry, which has been extensively quarried for aggregate at this site. It was intruded into the surrounding sandstones and marls at a time when these country rocks were cold. This created a marked temperature gradient between the sedimentary ‘country rocks’ and the hot, molten igneous intrusion and resulted in the formation of a baked margin.

There are no images available for this site.

Terminology

Dyke – A body of igneous rock that has been intruded into the surrounding rocks and has a ‘sheeted’ geometry. This ‘sheet’ cuts across the sedimentary layering in the surrounding rocks.

Marl – A type of mudstone that consists of clay and carbonate, i.e. a lime-rich mudstone.

Country rock – The host rock into which an igneous rock has been intruded. It is also termed ‘surrounding rocks’ in this entry.

Baked margin – The part of the country rock that is immediately adjacent to an igneous intrusion. High temperatures experienced by the country rock during the intrusion of an igneous body can cause clay-rich rocks to become baked in the immediate vicinity of the intrusion. The effect of this baking decreases with distance from the intrusion.

References

Bailey, E., 2002, ‘Malvern Hills – May 18th 2002’, Magazine of the Geologists Association, vol. 2, pp.10-11.

Baker, J.W., 1947, ‘The Geology of the West Malvern District’, Thesis, University of Birmingham, Birmingham, pp.48.

Bennett, A.G., 1942, The Geology of Malvernia, Malvern Naturalists’ Field Club, Malvern, pp.73

Duncan, C.C., 1928, ‘Southstone Rock and Brockhill’, Transactions of Worcester Naturalists Club, years 1923-31, pp. 299.

Guppy, E.M. and Sabine, P.A., 1956, ‘Chemical analysis of igneous rocks, metamorphic rocks and minerals’, Memoir of the British Geological Survey, London.

Hallimond, A., 1939, ‘Magnetic observations on the Brockhill Dyke’, Bulletin of the Geological Survey of Great Britain, vol. 2, pp.85-92

Hamblin, R.J.O., 1983, Geological notes and local details for 1:10000 sheet SP 07 SW (Alvechurch), British Geological Survey, London, pp.20.

Miller, C.G., 1995, ‘Ostracod and Conodont distribution across the Ludlow/Pridloi boundary of Wales and the Welsh Borderlands’, Palaeontology, vol. 38, pp. 341-384.

Murchison, R.I., 1839, The Silurian System, founded on geological researches in the counties of Salop, Hereford, Worcester and Stafford; with descriptions of the Coal fields and overlying formations, vo. 1,

John Murray, London, pp.185-194.

Penn, J.S.W., 1969, ‘The Silurian rocks of the west Malvern Hills from Clencher’s Mill to Knightsford Bridge’, PhD Thesis, University of London, London, pp.145.

Phillips, J., 1845, Brockhill dyke and quarry, Field notebook 5 Apr-22 Apr, Geological Survey of Great Britain, pp.55.

Phillips, J., 1848, ‘The Malvern Hills, compared with the Palaeozoic districts of Abberley, Woolhope, May Hill, Tortworth and Usk’, Memoir of the Geological Survey, vol. 2, pp. 330.

Reeve, F.A.E., 1953, ‘The structure of the Silurian rocks of the Malvern and Abberley hills Worcestershire’, PhD Thesis, University of Birmingham, Birmingham, pp.286,

Richards, T.D., Chapman, E., Ashbee, E. and Gillespie, R., 2008, Worcestershire Geodiversity Action Plan phase 2: Geodiversity Audit. Final Report, Herefordshire and Worcestershire Earth Heritage Trust, Worcester, pp.79pp.

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Callow Hill Quarry

Exposed Units: Etruria Formation

Alternative site names: Wyre Forest Visitors Centre Quarry

Access: Open to public

The Wyre Forest Visitors Centre Quarry is located on the southern border of the Wyre Forest, approximately ½ a kilometre to the NW of the Forestry Commission’s visitor centre. The quarry is small; 20m long, 15m wide and 5m high. There are two small exposures, both located on the eastern side of the quarry.

The rock exposures reveal two main rock types; coarse red sandstone and a red conglomerate belonging to the Etruria Formation. The lower beds are made of sandstone, which also contain iron nodules. The sandstone is overlain by alternating bands of sandstone and conglomerate. Within the south-east rock face, two of these conglomerate beds are separated by a palaeosol (a fossil soil) layer about 30cm thick, which also contains iron nodules. Sandstone overlies the conglomerate beds.

The conglomerates represent sheet flood deposits within an alluvial fan system. They were deposited by repeated flash floods, rivers, and mudflows, which eventually coalesced to form a fan-shaped deposit at the edge of the sedimentary basins in the area. These sequences of conglomerates are often separated by mudstones and palaeosols. The palaeosols formed during periods when the ground became swampy and waterlogged. The soil was then buried and underwent complete oxidation giving the beds their red colour. Siderite (iron carbonate) nodules and bedded ironstones present were oxidised to form the mineral haematite as a result of this burial.

The quarry was quarried for the conglomerates, as they would have been crushed and used as aggregate for local building work. The iron nodules may also have been used as a source of iron ore for the local iron industry.

This site is part of the Community Earth Heritage Champions Project.

Photos

Rock faces in quarry

Rock faces in the quarry.

Conglomeratic bed within the Etruria Formation.

Haematite nodules in the palaeosol layer.


 

 

 

 

 

 

 

References

Besly, B.M. and Turner, P. 1983. Origin of red beds in a moist tropical climate (Etruria Formation, Upper Carboniferous, UK). in WILSON, RCL (ED), ‘Residual deposits’, Spec Publ Geol Soc Lond, 11, pp. 131-147.

Brenchley, P.J. and Rawson, P.F. 2006. The Geology of England and Wales. The Geological Society. The Geological Society Publishing House, Bath.

Mitchell, G.H. et al. 1962. Geology of the country around Droitwich, Abberley and Kidderminster. British Geological Survey Memoir.

Tucker, M.E. 2001. Sedimentary Petrology (3rd Edition). Blackwell Scientific Publications.

Woodcock, N. and Strachan, R. 2000. Geological History of Britain and Ireland. Blackwell Scientific Publications.

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Dales Hall Quarry

Exposed units: Warren House Formation

The quarry lies on the northeast corner of Hangman’s Hill and 160m northwest of Dales Hall.  About 12m of crag is exposed at present. Removal of the loose soil cover would easily expose more.  The unit is a type of basalt called spilite (basalt that has been chemically altered by reacting with sea water) and is part of the Precambrian Warren House Formation.  Rocks at the eastern end of the site preserve pillow lavas, further suggestive of the unit’s eruption under water. Sections through the pillows measure approximately 1m x 30cm, with a vertical long axis. During eruption, the long axis of pillow structures will be oriented in the direction that the lava was travelling and therefore will be lain down at an angle close to horizontal. Vertically oriented long axes in the current outcrop therefore indicate that that the Warren House Formation has been subsequently tilted away from horizontal.  The top of the unit is present in the north side of the quarry, which comprises about 5cm of broken rock.

 

Photos

General view of the remaining back face of Dales Hall Quarry.

Buttress showing pillows lavas in the Warren House Formation.

Detail of oval-shaped pillow lavas. Lens cap for scale.

 

 

 

 

 

 

 

 

References

Platt, J.I., 1933, ‘The petrology of the Warren House series’, Geological Magazine, vol.70, pp. 423-429.

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Dingle Quarry

Exposed Units: Malverns Complex

Conservation Status: Local Geological Site; SSSI; Within an AONB

Dingle Quarry is split into three different levels: Lower, Middle and Upper Dingle. Lower Dingle is located to the rear of a bus stop, with much of the exposure obscured by vegetation. Middle and Upper Dingle are located off a path directly above the bus stop. Middle Dingle can be easily accessed, whereas Upper Dingle can not be accessed safely.

Middle and Upper Dingle:

Diorite is the predominant rock type in Dingle Quarry, which is intruded by granites and a large dolerite dyke.

The dolerite dyke is 4m thick and forms a step in the quarry floor which separates Middle Dingle from Upper Dingle. The dyke is orientated NW/SE. The precise age of the dyke is unknown, but it is one of the youngest features within the quarry as it intersects the diorite mass, as well as the smaller granitic veins and intrusions. The lack of foliation in the dolerite indicates that it was intruded after the period of compression that gives the granites and diorite mass their foliated fabric. A chilled margin can be viewed in places where the dolerite was intruded into cold country rocks (i.e. the granites and diorite had already cooled down).

As well as the dolerite dyke there are some small granitic intrusions in the diorite, which are truncated by the dyke. Granite is also present in the north-east corner of the quarry. The granites and diorites in the quarry are foliated, which formed during compressional deformation that took place during the Precambrian era of geological time.

Dingle Quarry provides geologists with the opportunity to view the order of events that occurred to create this part of the Malvern Hills:

  • Intrusion of the main diorite mass
  • Intrusion of the small granitic veins
  • Diorites and granites were compressed to produce the foliated fabric
  • Intrusion of second phase of granitic material (evidence from lack of foliation)
  • Intrusion of dolerite dyke

Normal faulting occurs between the dolerite dyke and underlying diorites.

This site is part of the Community Earth Heritage Champions Project.

Terminology

Dyke – A sheet like, near vertical minor intrusion.

Chilled margin – The fine grained, outer layer of an igneous body formed by rapid cooling

Photos

 

General view of Lower Dingle

General view of Lower Dingle

General view of Lower Dingle

Middle and Upper Dingle quarry. Dolerite dyke seen as step separating the two levels as a step.

Diagram illustrating the relationships between different rock types at Dingle Quarry.

Sharp contact between the dolerite dyke (bottom) and Malverns Complex granite (top).

Diagram illustrating calcite mineralisation at the boundary between the dolerite dyke and Malverns Complex granite.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

Barclay W.J. et al. (1997) Geology of the county around Worcester. British Geological Society Memoir. London.

British Geological Survey (1993) Geology of the country around Worcester. Sheet 199: 1:50,000

Bullard D.W. (1989) Malvern Hills; A student’s guide to the geology of the Malverns. Nature Conservancy Council. Peterborough.

Butcher N.E. (1962) The Tectonic Structure of the Malvern Hills. Proc. Geol. Soc. 73 pp.103-123.

Falcon N.L (1947) Major Clues in the Tectonic History of the Malverns.

Fitch F.J. (1966) Isotopic age determinations on rocks from Wales and the Welsh Borderland. pp. 22-45 in Pre-Cambrian and Lower Palaeozoic rocks of Wales. Wood, A (Editor). University of Wales Press.

Kellaway G.A. and Hancock P.L. (1983) Structure of the Bristol District, Forest of Dean and the Malvern Fault Zone. in The Variscan Fold Belt in the British Isles. Hancock P.L. (Editor). Adam Hilger LTD. Bristol.

Lambert R. St J. and Holland J.G. (1971) The Petrography and Chemistry of the Igneous Complex of the Malvern Hills, England. Proc. Geol. Ass. 82. pp. 323-352.

Penn J.S.W. and French J. (1971) No 4: The Malvern Hills. Geologists Association Guides.

Pharoah T.C. et al. (1987) Geochemical Evidence of the Tectonic Setting of Late Proterozoic Volcanic Suites in central England. Geol. Soc. Special Publication No. 33. pp. 541-552.

Pharoah T.C and Gibbons W. (1994) Chapter 10: Precambrian rocks in England and Wales south of the Menai Strait Fault System. from Gibbons W. and Harris A.L: A revised correlation of Precambrian rocks in the British Isles. Geol. Soc. Special Report No. 22.

Phipps C.B. and Reeve F.A.E. (1967) Stratigraphy and Geological History of Malvern, Abberley and Ledbury. Geological Journal. 5 (2).

Timins Rev J.H. (1867). On the Chemical Geology of the Malvern Hills. Proc. Geol. Soc.

Thorpe R.S. (1972) Possible subduction zone origin for two calc-alkaline plutonic complexes from Southern Britain. Bulletin of the Geological Society of America. 83 pp. 115-120.

Thorpe R.S. (1987) Psuedotachylite from a Precambrian shear zone in the Malvern Hills. Proc. Geol. Ass. 98 (3) pp. 205-210.

Tucker R.D. and Pharoah T.C. (1991) U-Pb zircon ages for Late Precambrian igneous rocks in Southern Britain. Journal of the Geological Society. 148 pp. 435-443.

Woodcock, N and Strachan, R. 2000.Geological History of Britain and Ireland. Blackwell Publishing.

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Earnslaw Quarry

Exposed Units: Malverns Complex

Alternative Site names: Lower Tolgate Quarry, Wyche Quarry

Conservation Status: Local Geological Site

The Malverns Complex at Earnslaw Quarry is mostly represented by coarse grained pink granite that is tinged green in places because of the presence of the mineral chlorite. Diorite is present in the north of the quarry but is separated from the granite by a fault zone. Exposed in the quarry are the contacts between the Malverns Complex and two younger intrusive rocks. The smaller of these intrusions is a ~20cm thick microdiorite dyke that intrudes the granite at a high angle. Minor copper mineralisation has taken place at this site.

The second intrusion is a potassium-rich trachyte dyke that forms an east-west step across the quarry floor in the south part of the quarry.  This is the only intrusion of its kind in the Malverns Complex. It is a fine-grained, dull grey rock with scattered spots and veins of carbonate. It is composed mostly of the mineral potassium feldspar with minor chlorite, iron-titanium oxides, a colourless fibrous mineral and quartz.  Pseudomorphs of the mineral nepheline may also be present.

The intrusion exhibits a marked chilled margin, indicating its intrusion into the granite after it had cooled and solidified. Coarse-grained carbonate patches occur in the centre of the intrusion and in the highly deformed margin of the granite, which also contains common carbonate veins. Carbonate mineralisation occurred either during or after the intrusion of the trachyte, as it cross cuts both the granite and the trachyte.

The trachyte dyke crops out on an E-W step across the southern part of the quarry, and appears to be confined to the western part of the step. It is perhaps truncated by a NNE fault running parallel to the trend of the quarry. It runs NW-SE and is oriented near-vertical, and may be Caledonian in age. A fault zone immediately to the north of the body separates diorite to the north from coarse-grained, pink granite to the south.

Terminology

Trachyte – Fine grained igneous rock dominated by the mineral potassium feldspar, with smaller amounts plagioclase feldspar and either quartz or a feldspathoid mineral, such as nepheline.

Microdiorite – Fine-medium grain igneous rock containing the minerals plagioclase feldspar, iron- or magnesium-bearing minerals, such as amphibole or pyroxene, and up to 10% quartz.

Calendonian – Descriptive term for rocks/structures formed during the Caledonian orogeny, a period of mountain building in Britain, North America and Scandinavia that took place ~400 million years ago.

Photos

General view of the lake and land slip at the Earnslaw Quarry.

The scar left by the landslip exposes Malverns Complex diorite that is cut by pale pink pegmatite. The top of the scree slope left by the land slip is visible towards the bottom of the image.

The quarry face behind the upper car park at Earnslaw Quarry.

 

 

 

 

 

 

 

 

 

 

Granite pegmatite vein intruding altered ultramafic rocks between the upper and lower car park.

 

 

 

 

 

 

 

 

References

Barclay, W.J., Ambrose, K., Chadwick, R.A., and Pharaoh, T.C., (1997), ‘Geology of the country around Worcester’, Memoir of the British Geological Survey, British Geological Survey, London.

Beckinsale, R.D., Thorpe, R.S., Pankhurst, R.J. and Evans, J.A., 1981, ‘Rb-Sr whole rock isochron evidence for the age of the Malvern Hills Complex’, Journal of the Geological Society, London, vol. 138, 1, pp. 69-73.

Carney, J.N., Horak, J.M., Pharaoh, T.C., Gibbons, W., Wilson, D., Barclay, W.J., Bevins, R.E., Cope, J.C.W. & Ford, T.D., 2000, ‘Precambrian Rocks of England and Wales’, Geological Conservation Review, 20, Joint Nature Conservation Committee, Peterborough.

Thorpe, R.S., 1987, ‘Pseudotachylite from a Precambrian shear zone in the Malvern Hills’ Proceedings of the Geologists’ Association, vol. 98, 3, pp. 205-210.

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Hagley Hall Quarry

Exposed Units: Kidderminster Formation

Conservation Status: Local Geological Site

The best exposure of the Kidderminster Formation is seen in a disused quarry on the grounds of the Hagley Hall Estate.

The exposure comprises nearly 10m of continuous section and exhibits a mostly clast supported conglomerate with a fine, poorly cemented sandy matrix. The unit is red in colour indicating the presence of oxidised iron in the rock. The distribution of clasts varies and in some parts, bands of matrix supported conglomerate become pre-dominant. Clasts consist of rounded to subrounded pebbles composed of quartzite and lithic fragments, possible of igneous rocks and limestone. Size averages ~4cm, but varies from 1cm to 20cm. The unit is generally unsorted, although possible imbrication is present in places.

Terminology

Conglomerate - Sedimentary rock composed of coarse (≥1cm) rounded to sub-rounded pebbles contained within a fine grained matrix.

Lithic fragments – Pebbles that are made of pieces of rocks that have been eroded and incorporate into the conglomerate.

Imbrication – Vertical stacking of clasts in a sedimentary rock formed by currents.

Photos

Site photograph of Kidderminster Formation at Hagley Hall Quarry.

Close-up of pebble beds in the Kidderminster Formation. Image shows clast-supported rounded to subrounded pebbles of quartz (white) and other lithic fragments (brown) in a matrix of fine red sand. The conglomerate at the top and bottom of the photograph is clast-supported, with a more matrix-supported band in the middle denoted by the area with fewer clasts. Scale: Tape measure ~30cm

 

 

 

 

 

 

 

 

 

 

 

 

 

References

Whitehead, P.F. and Pocock, R.W., 1947, ‘Geology of the country between Dudley and Bridgnorth’, Memoir of the British Geological Survey, British Geology Survey, London.

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Hangman’s Hill Quarry

Exposed Units: Warren House Formation

This location is a disused quarry on Hangman’s Hill, lying approximately on the 250m contour and overlooking Dales Hall. The quarry has been worked on more than one level but only the top one is now exposed. A few rocks apparently in situ are seen lower down.

The exposed rocks are dominated by black ignimbrite at the south end of the quarry and a grey-coloured, very fine grained rhyolite towards the north end of the quarry.

Site is more easily accessed than Reservoir quarry and shows similar rocks, but more weathered.

Terminology

Ignimbrite – A destructive flow of volcanic ash, gases and rock particles that is erupted violently from a volcano.

Rhyolite – A fine grained volcanic rock, with a similar chemistry to granite.

Photos

Panoramic view of the remaining face at Hangman’s Hill Quarry. A natural outcrop of Warren House Formation is visible in the background.

 

 

References

Platt, J.I., (1933), ‘The petrology of the Warren House series’, Geological Magazine, vol. 70, pp. 423-429

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Hollybush Quarries

Exposed Units: Malvern Complex, Malvern Quartzite, Hollybush Sandstone

Conservation Status: Site of Special Scientific Interest

The Hollybush Quarries comprises three quarries: Slasher’s Quarry (which is described in a separate entry) and Hollybush Quarry are two very large disused quarries that lie on the Herefordshire – Worcestershire boundary; Middle Hollybush Quarry is a smaller working quarry that lies in between the larger quarries. Hollybush Quarry is the easternmost quarry and has its main entrance in Worcestershire. Slashers Quarry and Middle Hollybush Quarry lie to the west of Hollybush Quarry and are situated on private land in Herefordshire.

The complex presents some of the best and most extensive exposures of Malverns Complex meta-igneous rocks in the Malvern Hills.

Middle Hollybush Quarry

This is a small subsidiary quarry between Slashers Quarry and Hollybush Quarry. It exposes the basal Malvern Quartzite, which occurs in a faulted sliver that runs north-south and overlies the intermediate igneous rocks of the Malverns Complex. The quartzite is tough, pale grey, and locally pebbly and conglomeratic.

Hollybush Quarry

A fault running north-south on the western side of this quarry has brought the Malvern Quartzite down to lie alongside the Malvern Complex. Exposures in this block in show the unconformable sedimentary boundary of the Malvern Quartzite, where it lies directly on the granite and intermediate rocks of the Malverns Complex.

Terminology

Ultrabasic rock – Igneous rocks that dominantly contain minerals made up of iron and magnesium. They contain very little silica and so never contain the mineral quartz.

Limonite – Generic term used to describe hydrous (water-bearing) or anhydrous (non-water bearing) oxides of iron that cannot easily be differentiated from each other because of similarities in their physical characteristics. Usually, but not exclusively, limonite refers to the mineral ‘goethite’.

Photos

View of Hollybush Quarry looking east.

The unconformable contact between the Malverns Complex and Malvern Quartzite at Middle Hollybush Quarry.

 

 

 

 

 

 

 

 

 

References

Jones, R.K., Brooks, M., Bassett, M.G., Austin, R.L. and Aldridge, R.J., 1969, ‘An Upper Llandovery limestone overlying Hollybush Sandstone (Cambrian) in Hollybush Quarry, Malvern Hills’. Geological Magazine, vol. 106, 5, pp. 457-469.

Moorlock, B.S.P., 1986, Geological notes and local details for 1:10 000 sheets: SO 73NE (South Malvern Hills). British Geological Survey report, London.

Penn, J.S.W., and French, J., 1971, ‘The Malvern Hills’ Geologists’ Association Guide, Geologists’ Association.

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Knightsford Bridge Quarry

Exposed Units: Aymestry Limestone

At this disused quarry, the Amestry Limestone Formation has been overturned and the beds are highly fractured with some mineralisation in the joints.  The beds exposed in the quarry show a ~15m high section of calcareous siltstones and silty limestones.  The lowest part of the section comprises thinly bedded silty limestone and limey mudstones that contain abundant brachiopod shells. Above these, a ~8m succession of thinly bedded limestones contains increasing amounts of sandy material moving up through the sequence.  This is overlain by ~13m of limey silt that contains abundant examples of several species of brachiopod, as does the topmost layer of silt and fine-grained limestone. Although the sequence is similar in terms of rock type, the layers contain distinct assemblages of certain species of the brachiopod animal, which have been used to date the rock unit here to the mid-Silurian period of geological time.

Photos

Dipping beds of Aymestry Limestone at Knightsford Bridge Quarry.

Dipping beds of Aymestry Limestone at Knightsford Bridge Quarry.

Small scale faulting displacing calcareous shale beds in the Aymestry Limestone.

Brachiopod shell.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

Barclay, W.J., Ambrose, K., Chadwick, R.A., and Pharaoh, T.C., 1997, ‘Geology of the country around Worcester’, Memoirs of the British Geological Survey, British Geological Survey, London.

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Leach Green Quarry

Exposed Units: Lickey Quartzite

At the disused Leach Green Quarry, the Lickey Quartzite varies from fine grained and white, to coarse, grey and pebbly. It forms massive beds up to about 1m thick, which were lithified and fractured early in the unit’s history. The Lickey Quartzite was exposed at the surface during the Llandovery period of geological time (444-428 million years ago) and represented the floor of a shallow sea at this time. The fractures in the quartzite have been filled up by sandy material deposited in this Llandovery-age sea.

No images are available for this site.

Terminology

Massive – Term used to describe a rock unit that has no visible layering (e.g. bedding).

Lithified– Turned from sediment into rock.

References

Old, R.A., Hamblin, R.J.O., Ambrose, K., and Warrington, G., 1991, ‘Geology of the country around Redditch, Sheet 183’, Memoir of the British Geological Survey, London.

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Leigh Quarry

Exposed rock units: Cowleigh Park Formation

This long-disused quarry has been extracted on two levels and exposes low 50cm-2.5m faces that have been largely obscured by vegetation. The best exposure is seen on the south face of the quarry, where a 2.5m high face exhibits massive, fine-grained, buff-coloured sandstones that are separated by thin layers of red-coloured shale. Well-sorted sandstones form the dominant lithology at this site and form beds ranging in thickness from 20cm in the upper quarry, to greater than 1m thick in the lower quarry. The rocks at this site have been reported in the literature as Cowleigh Park Formation, however direct field observations indicate that the units are more similar to the younger Wyche Formation, which crops out about 50m to the south of the quarry.

Terminology

Feldspathic – containing the mineral feldspar.

Photos

View from the back of the upper quarry.

Exposure of well-bedded fine sandstone at the back face of the quarry.

Main exposure on the south face of the quarry.

 

 

 

 

 

 

 

 

Detail of massive, fine-grained sandstone and interbedded shale layers in the south face exposure.

Detail of shale interbeds in the south face exposure.

 

 

 

 

 

 

 

 

 

References

Barclay, W.J., Ambrose, K., Chadwick, R.A., and Pharaoh, T.C., 1997, ‘Geology of the country around Worcester’, Memoirs of the British Geological Survey, British Geological Survey, London.

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Barnt Green Road Quarry

Exposed Units: Lickey Quartzite Formation, Barnt Green Volcanics

Conservation Status: Local Geological Site

Access: Open to public

Barnt Green Road Quarry is located next to the Barnt Green Road at the eastern edge of the Lickey Hills Country Park and exposes the lowest part (but not the base) of the Lickey Quartzite Formation.

The quartzite in Barnt Green Road Quarry is pale grey to purple in colour and interbedded with thin shale/mudstone layers which could possibly be volcanic tuffs. The quartzites are immature to submature and forms flaggy beds 3-6cm in thickness that are separated by layers of sandy shale. Some of the quartzite bands are soft in texture and are composed of quartz and volcanic or tuffaceous material. The shaley layers are predominantly purple in colour and micaceous. The top most beds of the quarry face are sharply bent over from the south-east to the north-west in small recumbent folds. These overturned folds are well presented in Lapworth’s 1882 paper.

In the south-east corner of the quarry, to the left of a small normal fault, it is has been proposed that the boundary between the Lickey Hill Quartzite Formation and the Barnt Green Volcanics Formation can be found (Lapworth, 1882). The amount of volcanic material seems to increase towards the fault; this implies the boundary with the Barnt Green Volcanic Formation is close by. However, from studying the geological map, the Barnt Green Volcanic Formation is found much further to the south. The only way to determine whether the boundary is there is through excavation work.

The age of the formation has been the topic of much discussion, with many early authors like Lapworth, Boulton and Humphries placing the formation in the Cambrian. However since the use of radiometric dating to date rocks the formation has been placed in the Ordovician period, 510 – 439Ma. The Lickey Quartzite Formation itself was not dated as it contains no components used for radiometric dating; however the Barnt Green Volcanic Formation, believed to underlie the Lickey Quartzite Formation has been dated to the Tremadoc, 510Ma, thus giving a rough date for the Lickey Quartzite Formation.

This site is part of the Community Earth Heritage Champions Project.

Terminology

Volcanic Tuff – Consolidated volcanic ash.

Micaceous – A rock composed of a high percentage of the mineral mica (silicates of aluminium and potassium, and with magnesium and iron in the dark varieties).

Fold – A curved or angular shape of an originally planer geological structure.

Axial surface – The imaginary surface within a fold passing through and comprising all the hinges of the folded bedding surfaces.

Radiometric dating – A technique used to accurately date rocks using naturally occurring radioactive elements, such as Uranium.

Photos

 

Diagram showing relationships between hinge line, limbs and axial surface of a recumbent fold. In a recumbent fold, the hinge line and axial surface are both horizontal i.e. the structure is ‘lying down’.

ce of an overturned fold. In an overturned fold, axial surface and both fold limbs dip (tilt) in the same direction.

Diagram showing the relationships between the limbs and axial surface of an overturned fold. In an overturned fold, axial surface and both fold limbs dip (tilt) in the same direction.

Lickey Hills Lower Quarry.

 

 

 

 

 

 

 

 

 

 

 

Quarry face at Lickey Hills Lower Quarry.

Picture taken in the late 19th century (possibly taken by Lapworth) of the overfolding of the quartzite. Courtesy of the Lapworth Museum.

 

 

 

 

 

 

 

 

 

 

References

Boulton, W.S. 1928. The geology of the northern part of the Lickey Hills, near Birmingham. Geology Magazine, 65, 255-266.

British Geological Society (1996) Geology of the country around Birmingham. Sheet 168 (England and Wales), 1:50,000.

Eastwood, T. et al. 1925. The geology of the country around Birmingham. British Geological Survey Memoir.

Hardie, W.G. 1971. Lickey Hills, in Hardie, W.G. et al. Geology of the area around Birmingham (2nd Edition). Geologists Association Guide. (1) 12-15.

Hardie, W.G. 1991. A guide to the rocks and scenery of the Lickey Hills. B’ham: Lickey Hills Society. 27pp.

Humphries, J. 1897. Geology of the Lickey Hills. Transactions of the Worcestershire Naturalists Club, for 1897-9. 50-52.

Humphreys, J. 1922. The Lickey Hills. Transactions of the Worcestershire Naturalists Club, for 1918-1922. 370-373.

Lapworth, C. 1882. On the discovery of Cambrian rocks in the neighbourhood of Birmingham. Geology Magazine, 563-566

Old, R.A. et al. 1991. Geology of the country around Redditch. British Geological Survey Memoir.

Richardson, L. 1906. The geology of the Lickey Hills, near Birmingham. Cotswolds Naturalists Field Club, 7pp.

Tucker, M.E. 1991. Sedimentology Petrology (2nd Edition). Blackwell Scientific Publications.

Woodcock, N and Strachan, R. 2000.Geological History of Britain and Ireland. Blackwell Publishing.

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Warren Lane Quarry

Exposed Units: Lickey Quartzite Formation

Access: Private land

Warren Lane Quarry is a large quarry approximately 75m in length. The rock is exposed on the northern face of the quarry, and reaches approximately 10m in height. At the eastern end of the quarry there are large vehicle bays built into the quarry face.

The Lickey Quartzite Formation seen at the site is a pale grey, generally massive bedded (up to 50cm) sedimentary rock, with occasional thin silty beds occurring within the unit. The quartzite is a medium-grained, crystalline sub-arkose and there appears to be no significant variation in composition throughout the exposure. Freshly exposed faces are a creamy pink/white, with weathered faces a dull-grey.

To the west of the quarry, there is a fault that separates the Lickey Quartzite Formation from the younger red/orange marls of the Late Carboniferous-age Alveley Member (309 million years old). These marls are much softer than the quartzite and therefore erode quicker. This has led to the formation of the valley that separates Bilberry Hill from Beacon Hill. To the east of the quarry, the quartzite is separated by a fault from the Triassic conglomerates and sandstones of the Kidderminster Formation.

This site is part of the Community Earth Heritage Champions Project.

Terminology

Fault – A line of weakness within the Earth’s crust along which movement and displacement occurs.

Photos

Picture of the main rock face along the eastern side of the quarry.

The Lickey Quartzite in thin section. The rock is dominated by grey to black quartz, with rare grains of the mineral feldspar, which are the larger, grey grains in the centre of the image that show faint criss-crossed lines.

 

 

 

 

 

 

 

 

 

 

 

References

Boulton, W.S. 1928. The geology of the northern part of the Lickey Hills, near Birmingham. Geology Magazine, 65, 255-266.

British Geological Society (1996) Geology of the country around Birmingham. Sheet 168 (England and Wales), 1:50,000.

Eastwood, T. et al. 1925. The geology of the country around Birmingham. British Geological Survey Memoir.

Hardie, W.G. 1971. Lickey Hills, in Hardie, W.G. et al. Geology of the area around Birmingham (2nd Edition). Geologists Association Guide. (1) 12-15.

Hardie, W.G. 1991. A guide to the rocks and scenery of the Lickey Hills. B’ham: Lickey Hills Society. 27pp.

Humphries, J. 1897. Geology of the Lickey Hills. Transactions of the Worcestershire Naturalists Club, for 1897-9. 50-52.

Humphreys, J. 1922. The Lickey Hills. Transactions of the Worcestershire Naturalists Club, for 1918-1922. 370-373.

Lapworth, C. 1882. On the discovery of Cambrian rocks in the neighbourhood of Birmingham. Geology Magazine, 563-566

Old, R.A. et al. 1991. Geology of the country around Redditch. British Geological Survey Memoir.

Richardson, L. 1906. The geology of the Lickey Hills, near Birmingham. Cotswolds Naturalists Field Club, 7pp.

Tucker, M.E. 1991. Sedimentary Petrology (2nd Edition). Blackwell Scientific Publications.

Woodcock, N and Strachan, R. 2000.Geological History of Britain and Ireland. Blackwell Publishing.

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Longley Green Quarry

Exposed Rock Units: Aymestry Limestone, Upper Ludlow Shales

Conservation Status: Local Geological Site

The quarry face at Longley Green Quarry is about 15 m high and exposes the boundary between the Aymestry Limestone and the Upper Ludlow Shales. The Aymestry Limestone at this locality occurs at ground level on the east side of the site, where it is dominantly composed of thinly bedded or occasionally nodular silty limestone. Thin beds within the unit contain abundant brachiopod fossils and a number of sedimentary features, such as laminations and wave ripples are preserved.

The Upper Ludow Shales overlie the Aymestry Limestone and are limey siltstones with occasional thin beds of very shelley limestone. A thin bed in the central part of the exposure is made up of dark grey siltstone that is very fissile (flakey) but this gives way above and below to the pale-coloured limey siltstones.

The boundary between the two units is marked by a break in slope that forms a step in the outcrop; however the boundary itself has been buried by rubble that has fallen from further upslope.

One of the more interesting subjects on the Western side is the presence of a small normal fault where a cm-scale displacement cuts the Upper Ludlow Shales on the western side of the quarry. The thinly bedded rocks on either side of this fault show deformation consistent with the downward movement of the north side of the quarry relative to the south.

Terminology

Normal fault – A fault is a fracture in the Earth’s crust along which movement has occurred. A fault with a normal sense of motion formed as a result of being pulled apart but crustal forces.

Photos

General view of quarry face, showing beds of Aymestry Limestone dipping down towards the right of the image.

The change in slope angle that marks the boundary between Aymestry Limestone and the overlying Upper Ludlow Shales.

 

 

 

 

 

 

 

 

 

References

Barclay, W.J., Ambrose, K., Chadwick, R.A., and Pharaoh, T.C., 1997, ‘Geology of the country around Worcester’. Memoirs of the British Geological Survey, British Geological Survey, London.

Penn, J.S.W., 1969, The Silurian rocks of the west Malvern Hills from Clencher’s Mill to Knightsford Bridge, Thesis,  University of London, London, pp. 145.

Phipps, C.B. and Reeve, F.A.E., 1967, ‘Stratigraphy and geological history of the Malvern, Abberley and Ledbury Hills’, Geological Journal, vol. 5, pp. 339-368.

Rathbone, P.A., 1990, Geological structure of the Suckley area, Technical Report, British Geological Survey, London.

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Martley Rock

Exposed Units: Malverns Complex, Malvern Quartzite Formation, Raglan Mudstone Formation, Halesowen Formation

Access: Private land

Martley Pit exposes the most northerly outcrop of the Precambrian Malverns Complex, roughly 15 kilometres north of the main Malverns Complex exposure of the Malvern Hills ridgeline. This inlier of faulted Precambrian Malverns Complex and Cambrian Malvern Quartzite Formation is surrounded by strata of the Halesowen Formation, which unconformably overlies the Silurian Raglan Mudstone Formation.

The site is cut by two trenches. It is within the trenches that the rock units can be observed.

The composition of the Malverns complex rocks vary at the site from acidic to mafic meta-igneous rocks. Most exposures are heavily sheared altered granite/diorites which are also highly weathered.

The Malvern Quartzite is composed of almost wholly rounded grains of the mineral quartz, with some feldspar. The average grain-size is about 0 -5 mm which are bound by quartz cement. The majority of the exposures are stained yellow.

Silurian Raglan Mudstone Formation is seen in the floor of the far western trunk of the trench. It is a dark red-brown mudstone with occasional green spotting.

The Carboniferous Halesowen Formation seen contains a number of layers of wide ranging colours (green-grey, black, dark grey, orange and cream) dipping at a shallow angle to WNW.  The Halesowen Formation lies unconformably on the Raglan Mudstone Formation. Green-grey micacous sandstone has been observed at the site which may Carboniferous in age.

The site is bounded and cross cut by a number of faults. The Cambrian and Precambrian aged rocks have been heavily sheared to varying degrees across the site.

This site is also known locally as White Cottage Coppice, Martley Gravel Pit and Martley Pit.

Terminology

Inlier – An area of older rocks surrounded by younger rocks.

Unconformably –  Where two adjacent rocks units are of markedly different ages, indicating a gap in geological time

Acidic meta-igneous rocks – Rocks comprising more than 10% silica minerals (commonly quartz)

Mafic meta-igneous rocks – Rocks comprising les than 10% silica minerals

Sheared Where a rock is subject to directional stress (i.e. pressure with a directional element), minerals in the rock to realign according to the direction in which the pressure is directed.

Micaceous – A rock composed of a high percentage of the mineral mica (silicates of aluminium and potassium, and with magnesium and iron in the dark varieties

Fault – A line of weakness within the Earth’s crust along which movement and displacement occurs.

Photos

 

Martley pit trench showing Malverns Complex and Malvern Quartzite Formation units.

Near western end of the long trench. Raglan Mudstone Formation in the floor of the trench. Halesowen Formation in a variety of colours in the trench walls.

Malvern Quartzite Formation.

 

 

 

 

 

 

 

 

 

 

A shear zone in a faulted block of Malvern Quartzite Formation rocks.

Malverns Complex; Quartz-plagioclase rock with minor chlorite and white mica minerals.

 

 

 

 

 

 

 

 

 

References

BARCLAY, W.J. and RATHBONE, P.A. 1990, Geology of the Whitbourne district, British Geological Survey Technical Report, WA/90/90.

CALLAWAY, C. 1898, On a quartzite and syenite rock in Worcestershire, Geological Magazine, vol. 4, 5, pp.379.

COLES, C. St. A. 1898, An exposure of Quartzite and Syenite Rock near Martley, Worcestershire, Geological Magazine, vol. 4, 5, pp. 304-5.

EARP, J.R. and HAINS, B.A. 1971, The Welsh Borderland (Third Edition), British Regional Geology. Institute of Geological Sciences.

GROOM, T. 1898, Note on the Martley Quartzite, Geological Magazine, vol. 4, 5, pp. 562-4.

GROOM, T.T. 1900, On the geological structure of portions of the Malvern and Abberley Hills. Quarterly Journal of the Geological Society of London, vol. 56, pp. 138-97.

HOLLINGWORTH, S.E. 1938, In Summary of Progress of the Geological Survey of Great Britain for 1937, Part 1, 34.

MITCHELL, G.H., POCOCK, R.W. and TAYLOR, J.H. 1962, Geology of the country around Droitwich, Abberley and Kidderminster, Memoir of the Geological Survey of Great Britain.

MURCHISON, R.I. 1839, Silurian System. London.

PHILLIPS, J. 1848, The Malvern Hills compared with the Palaeozoic districts of Abberley, Woolhope, May Hill, Tortworth and Usk, Memoir of the Geological Survey of Great Britain, Vol. II, part I.

PHIPPS, C.B. and REEVE, F.A.E. 1969, Structural geology of the Malvern, Abberley and Ledbury hills. Quarterly Journal of the Geological Society, vol. 125, pp. 1-37.

SYMONDS, W.S. 1872, Records of the Rocks. London, John Murray.

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Shavers End Quarry

Exposed Units: Aymestry Limestone, Lower Ludlow Shales

Conservation Status: Local Geological Site

Shavers End Quarry is one of many quarries in the area located on the Abberley Hills, where the limestone is a sought after material for lime kilns, construction and the aggregates industry. Quarrying activity at Shavers End Quarry has sliced through the North West corner of Abberley Hill, providing a geological cross section for people to study the structure of the area in detail. The scale of the site, partnered with the bare rock faces allows visitors to fully appreciate the complex tectonic history of the area. Within the quarry there are two distinct rock formations exposed; the Lower Ludlow Shales Group and the Aymestry Limestone Formation.

The Lower Ludlow Shales Group is the lower of the two units and consists of a series of siltstones and bluish grey mudstones. These rocks can be best seen at the southern end of the quarry, as well as on the eastern banks of the quarry lakes. The Aymestry Limestone is a blue-grey, nodular argillaceous limestone and forms the main rock face that extends along the western side of the quarry. The limestone is shaly and impure and notably contains a thick band of bentonite.

Shavers End Quarry sits variably in the hinge zone and on the overturned limb of a large fold. The Lower Ludlow Shales and Aymestry Limestone at this locality are upside-down, suggested by the wrong-way-up orientation of fossils and other sedimentary structures. The age of folding has been the subject of much debate, with many different interpretations; it may have formed during the Variscan Orogeny (~300 million years ago); others suggested that folding occurred during the earlier Caledonian Orogeny (390 million years ago). However it is generally agreed that folding was instigated by thrust faulting on the East Malvern Fault system.

This site is part of the Community Earth Heritage Champions Project.

Terminology

Argillaceous limestone – limestone containing a small amount of clay minerals.

Bentonitic clay – Volcanic ash that has been chemically altered to form a type of clay.

Fold – Geological structure formed by the flexure of rock units, forming two fold limbs, separated by a hinge zone; rocks are literally folded.

Overturned limb – An arm of a fold that has been turned upside-down.

Orogeny – A period of mountain building.

Photos

View of the back face of Shaver’s End Quarry circa 2004.

Aerial view of Shavers End Quarry.

 

 

 

 

 

 

 

 

References

Mitchell, G.H., Pocock, R.W. and Taylor, J.H., 1962,Geology of the country around Droitwich, Abberley and Kidderminster’, Memoirs of the British Geological Survey, British Geological Survey. London.

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Sling Gravel Pit

Exposed Units: Clent Formation, Kidderminster Formation

Conservation Status: Site of Special Scientific Interest

The disused Sling Gravel Pit exposes the Clent Formation and the Kidderminster Formation; however most of the remaining faces show exposures of the Kidderminster Formation, whilst the Clent Formation is seen in a small faulted inlier.

The Clent Formation at Sling Gravel Pit is a breccia consisting of poorly sorted, angular, locally derived clasts, set in a matrix of sandy mudstone and mudstone. The clasts have been described as a mix of igneous intrusive and volcanic rocks, sandstones and limestones, probably derived from nearby Precambrian volcanics, Silurian sequences and the Lickey Quartzite respectively. The unit also contains derived fossils, most likely from the Silurian sandstones and limestones. The breccias contain rare cross-bedding, indicative of deposition in flowing water. The formation is interpreted as consisting of flash flood deposits.

At Sling Gravel Pit, the Kidderminster Formation lies unconformably over the Clent Formation. The unit here is represented by poorly sorted but well rounded pebbles ranging in size from 0.5-5cm that are thought to be sourced from south of the English Channel. The conglomerate varies from grain- to matrix supported. The clasts themselves are dominated by grey and red-brown quartzites and vein quartz but with minor amounts of Ordovician and Devonian-age sediments, volcanic and metamorphic material and rare grains of the mineral tourmaline. Derived fossils from the Ordovician and Devonian sediments are also present.

Terminology

Breccia – Sedimentary rock consisting of angular rock fragments that have been derived from other rock units and set in a background (or matrix) of fine grained sand, silt or mudstone. Breccias may be formed either by water transport or by shattering along a fault zone. The former interpretation is relevant to the Clent Formation.

Derived fossils – Fossils that have been weathered out of their host sedimentary rock and deposited in a younger rock via weathering, erosion and transport. Derived fossils are common in breccias and conglomerates.

Cross-bedding – Sedimentary structures formed by the formation of sand dunes and current ripples in moving water.

Unconformity (sic unconformably) – A surface between two rock units that represents missing time. An unconformable surface, which is typically an erosive surface, indicates that the deposition of rock units on either side was not continuous.

Photos

General view of lower quarry.

General view of lower quarry.

The step between the lower and upper quarries.

Exposed face showing red Clent Formation.

Detail of exposed face, showing unstructured, red sandstone with grit and pebble-sized clasts.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

King, W.W., 1893, ‘Clent Hill Breccias’, Midland Naturalist, vol. 16, pp.25-37.

Evans, D.H., 1992, Sling gravel pit SSSI: Geological site documentation/management brief, English Nature, London.

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Suckley Quarries

Exposed rock unit: Much Wenlock Limestone

Conservation Status: Local Geological Site

The Suckley Quarries are a line of quarries that run in a north-south direction through the east ridge of the Suckley Hills.  This ridge is defined by the Much Wenlock Limestone Formation, which is more resilient to weathering and erosion than the Upper Ludlow Shales Fomation to the west and therefore forms a well-defined ridge line.  The beds generally dip down towards the west, but this varies in places due to fault movements in the area.

The Much Wenlock Limestone at these sites is a grey, nodular limestone with a yellowish weathering colour. Some beds display lamination and small beds of shaley material commonly separate thicker beds of nodular limestone. Four different varieties of brachiopod fossil have been documented including Atrypa and Leptaena. Crinoid ossicles are common throughout the unit and rare bryozoan fossils are also present.

A variety of features are seen in these quarries, including current bedding, long crinoid stems (which are usually very fragile) and micritic limestone. These indicate a range of depositional environments ranging from energetic currents in shallow water to more placid, deeper water conditions.

These sites have produced stone for a variety of uses, aggregate being the principal product.  The nodular nature of the limestone certainly makes it useful as an aggregate, although more massive beds have been used locally as a building stone. The quarries may have also produced limestone for lime making, however the complete absence of lime kilns in the area suggests that this was not the principal purpose of the quarry.

Terminology

Crinoid ossicle – Small circular discs with a hole through the middle that represent a single segment in the stalk of a sea lily animal.

Bryozoa – Colonial filter feeding animals more commonly known as ‘moss animals’

Micritic limestone – Type of limestone formed from limey mud (micrite).

Photos

The Suckley Quarries are a series of steep-sided, linear trenches dug into the Much Wenlock Limestone.

Beds of steeply dipping limestone and nodular limestone in the Much Wenlock Formation.

Piles of overburden (unusable soil and rock that was removed during quarrying) at one of the Suckley sites.

Detail of the nodular limestone that is predominant at the quarry.

Brachiopod fossil.

Brachiopod fossil.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

Barclay, W.J., Ambrose, K., Chadwick, R.A., and Pharaoh, T.C., 1997, ‘Geology of the country around Worcester’, Memoirs of the British Geological Survey, British Geological Survey, London.

Penn, J.S.W., 1969, ‘The Silurian rocks of the west Malvern Hills from Clencher’s Mill to Knightsford Bridge’, Thesis, University of London, London, pp. 145.

Rathbone, P.A., 1990, Geological structure of the Suckley area, BGS Technical report, British Geological Survey, London.

Ray, D.C., and Thomas, A.T., 2007, ‘Carbonate depositional environments, sequence stratigraphy and exceptional skeletal preservation in the Much Wenlock Limestone Formation (Silurain) of Dudley, England’, Palaeontology, vol. 50, pp. 197-220.

Reeve, F.A.E., 1953, ‘The structure of the Silurain rocks of the Malvern and Abberley hills Worcestershire’, PhD thesis, University of Birmingham, Birmingham, pp. 286.

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Tarmac Quarries

Exposed Units: Post-Anglian Deposits (Worcester Member)

Conservation Status: Active quarry complexes – no public access

Two quarries operated by Tarmac Ltd. expose good sections of the post-Anglian Worcester Member, a sand and gravel terrace deposited by and around the ancient River Severn.

The terrace deposits at both sites are dominated by sand, with lesser amounts of gravel, silt and clay. Sand and gravel typically occur as well-bedded sequences, but gravel tends to be more common towards the base of the unit and is seen lying directly on the Triassic bedrock in places. The gravel beds are seen to truncate underlying sedimentary layers, suggesting that these layers have an erosive base. Imbrication and cross bedding is apparent in places, also indicating deposition in moving water. Individual beds also tend to get finer grained moving vertically upwards and may also be separated by a fine layer of silt or clay.

The features seen at these quarries suggest that the Worcester Member represents both river channel fill and sand/gravel bars that were laid down by a braided river system at the end of the Last Ice Age (the Devensian).

Terminology

Well-bedded – A rock unit that contains prominent sedimentary bedding (layering).

Imbrication – vertical stacking of clasts in a sedimentary rock formed by currents.

Photos

General view of one of the Tarmac quarries.

General view of extraction at one of the Tarmac quarries.

Active quarry face displaying alternating layers of sand and gravel.

Layers of sand and gravel containing a marked horizon of black peat, indicating that the sediments had been exposed at the surface long enough for vegetation to become established.

Sedimentary layering in a sand and clay succession within the sand and gravel unit.

Detail of the sedimentary layering in a sand and clay succession. The dark grey layer represents a band of organic material.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

Dawson, M.R. 1989, ‘The Severn Valley north of Bridgnorth’, In: Keen, D.H. (eds), The Pleistocene of the West Midlands Field Guide; Quaternary Research Association, Cambridge, pp. 78-100.

Maddy, D. & Lewis, S.G., 2005, ‘The Lower Severn Valley’, In: Lewis, C.A. and Richards, A.E. (eds), The glaciations of Wales and adjacent areas, 6, Logaston Press, Almeley, pp. 73-84.

Wills, L.J., 1938, ‘The Pleistocene development of the Severn from Bridgnorth to the sea‘,y Journal of the Geological Society, vol. 94, pp. 161-242.

Barclay, W.J., Ambrose, K., Chadwick, R.A., and Pharaoh, T.C., 1997, ‘Geology of the country around Worcester’, Memoirs of the British Geological Survey, London, pp. 156.

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Westminster Bank Quarry

Exposed Units: Malverns Complex

Conservation Status: Local Geological Site, SSSI

Westminster Bank Quarry is a large quarry on the western side of the Malvern Hills. The rock face runs along the eastern side of the site and is approximately 60m in length, and 20m high. The best exposure is found in the middle of the quarry face, the northern and southern parts of the quarry face are obscured by vegetation.

A narrow 2m band of diorite is present in the southernmost part of the quarry face, where it is faulted against granite. The diorites have undergone regional metamorphism, which means they have been subject to high temperatures and pressures in the past. During metamorphism, chemical reactions occur to create new minerals, and the minerals also elongate to produce the schistose fabric. Due to this alteration the diorite has a rotted appearance, with the chlorite and clay minerals developed from the breakdown of the minerals hornblende feldspar respectively.

Faulted against the diorite is coarse grained granite comprised of the minerals orthoclase feldspar and quartz; this is the dominant rock type at the site. These coarse grained granites vary throughout the 60m exposure; the northernmost granites are strongly foliated, with an 8m section where the granite has a gneissic appearance. In the southern half of the quarry, normal faulting introduces a complex sequence of granites and diorites, both of which have been extensively altered.

Westminster Bank Quarry affords views out across Herefordshire to Wales enabling people to view the changes in landscape and therefore the changes in geology. The undulating hills made of Silurian shales and limestones level out onto the Herefordshire plain, made of Devonian sandstones and mudstones. The Woolhope Dome rises out of this plain and forms a prominent feature in the landscape. On days when the weather is clear the Welsh Mountains can be seen.

This site is part of the Community Earth Heritage Champions Project.

Terminology

Fault – A line of weakness within the Earth’s crust along which movement and displacement occurs.

Normal Fault – Movement along a line of weakness in the Earth’s crust where the handing wall is displaced downwards relative to the footwall.

Schistose Fabric – A foliation produced by deformation in which tabular and platy minerals, coarse enough to be visible to the unaided eye, have a preferred orientation.

Gneissic appearance – A foliation of compositional layering, formed during deformation and metamorphism.

Dyke – A sheet like, near vertical minor intrusion.

Sheared – Where a rock is subject to directional stress (i.e. pressure with a directional element), minerals in the rock to realign according to the direction in which the pressure is directed.

Relative dating – Dating of rock units in relationship to each other e.g. rock A is younger than B but older than rock C.

Photos

Coarse granite in the centre of the quarry (Facing NE).

Close up of coarse granite from Westminster quarry.

Foliated granite with fault (Facing NE).

 

 

 

 

 

 

 

 

References

Barclay W.J. et al. (1997) Geology of the county around Worcester. British Geological Society Memoir. London.

British Geological Survey (1993) Geology of the country around Worcester. Sheet 199: 1:50,000

Bullard D.W. (1989) Malvern Hills; A student’s guide to the geology of the Malverns. Nature Conservancy Council. Peterborough.

Butcher N.E. (1962) The Tectonic Structure of the Malvern Hills. Proc. Geol. Soc. 73 pp.103-123.

Falcon N.L (1947) Major Clues in the Tectonic History of the Malverns.

Fitch F.J. (1966) Isotopic age determinations on rocks from Wales and the Welsh Borderland. pp. 22-45 in Pre-Cambrian and Lower Palaeozoic rocks of Wales. Wood, A (Editor). University of Wales Press.

Kellaway G.A. and Hancock P.L. (1983) Structure of the Bristol District, Forest of Dean and the Malvern Fault Zone. in The Variscan Fold Belt in the British Isles. Hancock P.L. (Editor). Adam Hilger LTD. Bristol.

Lambert R. St J. and Holland J.G. (1971) The Petrography and Chemistry of the Igneous Complex of the Malvern Hills, England. Proc. Geol. Ass. 82. pp. 323-352.

Penn J.S.W. and French J. (1971) No 4: The Malvern Hills. Geologists Association Guides.

Pharoah T.C. et al. (1987) Geochemical Evidence of the Tectonic Setting of Late Proterozoic Volcanic Suites in central England. Geol. Soc. Special Publication No. 33. pp. 541-552.

Pharoah T.C and Gibbons W. (1994) Chapter 10: Precambrian rocks in England and Wales south of the Menai Strait Fault System. from Gibbons W. and Harris A.L: A revised correlation of Precambrian rocks in the British Isles. Geol. Soc. Special Report No. 22.

Phipps C.B. and Reeve F.A.E. (1967) Stratigraphy and Geological History of Malvern, Abberley and Ledbury. Geological Journal. 5 (2).

Timins Rev J.H. (1867). On the Chemical Geology of the Malvern Hills. Proc. Geol. Soc.

Thorpe R.S. (1972) Possible subduction zone origin for two calc-alkaline plutonic complexes from Southern Britain. Bulletin of the Geological Society of America. 83 pp. 115-120.

Thorpe R.S. (1987) Psuedotachylite from a Precambrian shear zone in the Malvern Hills. Proc. Geol. Ass. 98 (3) pp. 205-210.

Tucker R.D. and Pharoah T.C. (1991) U-Pb zircon ages for Late Precambrian igneous rocks in Southern Britain. Journal of the Geological Society. 148 pp. 435-443.

Woodcock, N and Strachan, R. 2000.Geological History of Britain and Ireland. Blackwell Publishing.

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Whiteleaved Oak Quarry

Exposed rock units: Malverns Complex, Malvern Quartzite, Hollybush Sandstone

Conservation Status: Local Geological Site

This quarry exposes a wide range of intensely faulted Precambrian and Cambrian rocks, including distinctive blue-grey very fine grained schist that is defined by chlorite. In the northern part of the quarry, the boundary between the Malvern Complex granites and the Malvern Quartzite is exposed.   Along the western edge of the quarry, the Hollybush Sandstone is in contact with the Malvern Complex.

The Precambrian Malvern Complex at Whiteleaved Oak Quarry consists of intensely sheared granite in the form of bands of chlorite schist which wraps around eyes of coarser-grained granite pegmatite. The formation of the chlorite schist may be the result of shearing along the boundary with the Hollybush Sandstone.

The Cambrian Malvern Quartzite is a quartz-rich basal conglomerate that directly overlies the Malverns Complex granite. The conglomerate here is matrix-supported and contains clasts of quartz, minor feldspar and fragments of the Malverns Complex that may measure up to 15mm in diameter.

The Cambrian Hollybush Sandstone here is more impure than the Malvern Quartzite, containing higher proportions of feldspar and clay minerals. Brachiopod and trilobite fossils have been recorded in this unit. The Hollybush Sandstone in the north part of the quarry forms planar beds that have been subject to bending and minor fracturing. This deformation has been attributed to minor faulting in the area, which is also the likely cause of schist formation in the Malverns Complex.

The boundary between the three units in this quarry represents an onlap unconformity, which resulted from a sea level rise during the Cambrian. The Malvern Quartzite and Hollybush Sandstone were deposited on top of Malverns Complex, which were exposed at the surface or on the sea floor. The unconformity and the presence of Malvern Complex pebbles in the conglomerates proved in part that the Malvern Complex rocks were older than the Cambrian sequence. Until then, it was thought that the Malvern rocks had intruded into the Cambrian sequence and so were younger.

Terminology

Schist – A rock fabric formed by deformation that is planar in geometry and defined by platy (sheet-like) minerals, such as biotite, muscovite and chlorite.

Unconformity – A surface between two rock units that represents missing time. An unconformable surface, which is typically an erosive surface, indicates that the deposition of rock units on either side was not continuous.

Photos

General view of Malverns Complex granite at Whiteleaved Oak Quarry.

The unconformable contact between the Malverns Complex and overlying Malvern Quartzite.

The unconformable contact between the Malverns Complex and overlying Malvern Quartzite.

Detail of the basal conglomerate in the Malvern Quartzite, containing clasts of quartz, feldspar and fragments of Malverns Complex material.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

Bennett, A.G., 1942, ‘The Geology of Malvernia’, Transactions of the Malvern Naturalists’ Field Club, vol. 2, pp.73.

Bullard, D.W., 1989, Malvern Hills – A student’s guide to the geology of the Malverns, Joint Nature Conservancy Council, Peterborough.

Groom, T.T., 1899, ‘The geological structure of the southern Malvern Hills and of the adjacent district to the west’, Journal of the Geological Society, vol. 55, 1, pp. 129-169.

Holl, H.B., 1865, ‘On the geological structure of the Malvern Hills and adjacent districts’, Journal of the Geological Society, vol. 21, 1, pp. 72-102.

Metcalfe, H.F., 1913, ‘Cambrian rocks of the southern Malverns’, Transactions of Malvern Naturalists Field Club, for 1909-1915, pp. 75-84.

Penn, J.S.W., and French, J., 1971, The Malvern Hills, Geologists’ Association Guides, Geologists’ Association

Roberts, G.E., 1860. The rocks of Worcestershire: their mineral character and fossil contents, Joseph Masters, London, pp. 247.

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Witnell’s End Quarries

Exposed Units: Shatterford Dyke, Etruria Formation

The intrusion is widely known as the ‘Shatterford Dyke’, however the structure is apparently intruded parallel to the grain of the country rock, meaning that it is technically a sill.

The Witnell’s End Quarries are a series of at least six disused quarries scattered in woodland along a prominent ridge. It is bounded in the west by a stream and in the east by the eastward sloping ridge-side. There is evidence of significant quarrying with some good exposures, plenty of quarry waste and scree. There are also good natural outcrops in the stream bed.

The intrusion is well exposed in two of the quarries, where it has a dolerite composition. It is a hard, dark grey, fine-grained rock with well defined jointing that dips steeply to the east. Spheroidal weathering is present in some of the exposures and where it has been intensely weathered, the rock takes on a brown colouring and is more prone to erosion – this eroded material forms the scree deposits.

The Shatterford Dyke is intruded into the Etruria Formation, which consist of grey, brown and red clays and are seen towards the north end of the area of interest. It is possible that the contact between the dolerite intrusion and the host sedimentary rocks may be exposed in a stream bed but this has not yet been located.

Terminology

Dyke/sill – A body of igneous rock that has been intruded into the surrounding rocks and has a ‘sheeted’ geometry. In a dyke, this ‘sheet’, cuts across the sedimentary layering in the surrounding rocks. In a sill, the sheet is intruded parallel to layering in the surrounding rock.

Spheroidal weathering – A weathering process, whereby shells of surface material on a rock face flake off, leaving ‘spherical’ bulges on the rock face (see picture).

Photos

General view of the exposure at Witnell’s End Quarries.

General view of the exposure at Witnell’s End Quarries.

Spheroidal weathering in the dolerite dyke.

 

 

 

 

 

 

 

 

Exposures of dolerite in the path near to the Witnell’s End Quarries.

 

 

 

 

 

 

 

 

References

Anon, 1990, Special wildlife sites in Hereford and Worcester with geological interest, Worcestershire Nature Conservation Trust, pp. 13.

Fitch F.J. and Williams, S.C., 1970, ‘Isotopic ages of British Carboniferous rocks’, Conference Report, 6th Congress of International Stratigraphy, Sheffield, vol. 2, pp.771-789.

King, W.W., 1921, ‘The geology of Trimpley’, Transactions of the Worcestershire Naturalists’ Club, vol. 7, 4, pp. 319-322.

Whitehead, T.H. and Pocock, R.W., 1947, ‘Dudley and Bridgnorth, Sheet 167’, Memoir of the Geological Survey of Great Britain, London, pp.  226.

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Woodbury Quarry

Exposed Rock units: Lower Ludlow Shales, Aymestry Limestone, Upper Ludlow Shales, Anglian Deposits (Wolston Formation)

Conservation Status: Site of Special Scientific Interes, Local Geological Site

Woodbury Quarry exposes a complete succession through the Ludlow Shales and Aymestry Limestone Formations.  It is a unique site and one of the finest Silurian sections in the Welsh Borderlands.  This active quarry provides extensive and continuous exposure through much of the Mid-Silurian and the whole of the Upper Silurian succession of the Abberley area.  The highly fossiliferous rocks, coupled with the interesting sedimentology, make this locality a very important site for continuing research into Silurian palaeontology and palaeoenvironments.

The Lower Ludlow Shales at this site comprises buff coloured shales with thin limestone bands and nodules.  Towards the top of the succession, a 35cm thick, bentonitic clay is present. The fauna is rich and varied with brachiopods, trilobites, cephalopods and ostracods being commonly found.  Rare corals, bivalves and gastropods also occur.

The Aymestry Limestone Formation at Woodbury Quarry is variably made up of silty limestones and nodular limestones, with a poor fossil content that includes brachiopods and rare bivalves, gastropods and corals.

The entire succession of the Upper Ludlow Shales is preserved, encompassing the Mocktree Shale Member, the Woodbury Shale Member and the Whitcliffe Flags Member.  These three units are dominated by calcareous siltstones, although limestones are more common in the Mocktree Shale Member. The units are defined in the quarry by their differing faunal successions, which contain varying species of brachiopods, bivalves, cephalopods, gastropods, ostracods, corals and trilobites.

A rare exposure of Anglian-age deposits rests unconformably on rocks of the Aymestry Limestone Formation.  The unconformity is well displayed on an extensive quarry bench. The basal bed of the sequence is a till that contains fragments of Devonian- and Silurian-age material.  This is overlain by red-brown fluvio-glacial silts, sands and gravels showing current bedding, imbrication and channels.  Part of the exposure shows yellow sands with coal clasts and derived fossils are common.

Other rock units are also present at Woodbury Quarry, such as the World-famous Ludlow Bone Bed and Downton Castle Sandstone which sequentially overlie the Whitcliffe Flags Member. These are not extracted for aggregate and so are not considered further.

Terminology

Fossiliferous – Containing fossils.

Bentonitic (sic bentonite) – Clay layers formed from the alteration of volcanic ash.

Imbrication – vertical stacking of clasts in a sedimentary rock formed by currents.

Photos

View of the main face of Woodbury Quarry looking northeast. Beds dip steeply to the east and are almost vertical in places. The Lower Ludlow Shales are exposed in the right hand side of the photo as a buff-coloured rock. To the left of this is the pale-grey Aymestry Limestone.

View of Woodbury looking east. This image shows the buff-coloured Lower Ludlow Shales overlain by the Anglian-age Wolston Formation. A bench forms directly on top of the cliff face and the Wolston Formation lies on top of this bench, where it forms a thick layer of pale brown sediments.

Active quarrying at Woodbury Quarry during the late 1990’s.

 

 

 

 

 

 

 

 

 

 

 

 

References

Cottle, R., 1993, Woodbury quarry SSSI: Geological site documentation/management brief, English Nature, London.

Lawson, J.D., 1956,The Ludlovian rocks of the Welsh Borderland’, The Advancement of Science, vol. 12, pp. 563-570.

Holland, C.H., Lawson, J.D., and Walmsley, V.G.A., 1959, ‘Revised classification of the Ludlovian succession at Ludlow’, Nature, vol. 184, pp. 1037.

Phipps, C.B., 1957, ‘The structure and Stratigraphy of the Silurian rocks West of the South Malvern Hills’, PhD Thesis, University of Birmingham, Birmingham, pp. 235.

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