The Ercall
Encyclopedia
The Ercall, sometimes known as Ercall Hill, is a small hill in the ceremonial county
of Shropshire
, England
. It is located between The Wrekin
and Wellington
, in the Telford & Wrekin borough. It is regarded as an internationally important geological site, which is part of The Wrekin and The Ercall Site of Special Scientific Interest (SSSI). The hill is managed by Shropshire Wildlife Trust
. The site includes 540 million year old ripple beds and ancient pre-Cambrian lava flows in exposed quarries. http://www.shropshirewildlifetrust.org.uk/wp_22_ercall.html Quartzite
from the neighbouring Wrekin is also visible. The Ercall bears the marks of extensive quarrying, although the quarries are now disused, safe and open to the public. When the M54 motorway
was constructed in 1974, the road was built through the northern end of the hill.
species. In the summer, the Ercall Woods which line the hill are a favourite habitat for the Speckled Wood
and during spring when the forest is laden with bluebells
, the Dingy Skipper
can arrive in great numbers. The exposed quarries are popular with other butterfly species, including the Green Hairstreak
and Wall, which like to bask in sheltered spots.
On the upper slopes of the hill tall oak
trees predominate. Acidic soils support such plants as bilberry
, climbing corydalis
and heath bedstraw. The Green woodpecker
is also present in the woods.http://www.shropshirewildlifetrust.org.uk/pdfs/ercall_walks.pdf
nearby; exit the M54 motorway
at J7 (last exit) or the last junction of the A5 from Shrewsbury
before it becomes the M54. From there The Wrekin is signposted; follow this road until you reach The Wrekin, then follow the sign for the Buckatree Hotel. There is a small car park across the road from this pub/hotel, and the entrance is clearly visible.
one encounters an old quarry with many distinctive geological features evident. http://www.shropshiregeology.org.uk
This is the first quarry that is apparent in the Ercall, it comprises Uriconian
Volcanic deposits of Precambrian
age. Such volcanic deposits are noted to have been bimodal and potentially intraplate possibly induced by (and therefore close to a) subduction zone and possibly in an island arc setting. The flow banding and fine to medium grained appearance of the deposit suggests a fairly rapid cooling event and appears to have been deposited in a submerged environment. In all likelihood, during such events the depositional environment would fluctuate between submarine and subaerial as sea-floor levels will have fluctuated as well as eustatic sea-levels.
On the right had side of the picture (running vertical) a dark grey doleritic dyke is evident. The dyke trends at approximately 65 degrees. Dolerite is intrusive and is relative to basalt
(extrusive). There is a significant alteration about the contact between the two rocks. The dolerite dyke was emplaced into the Uriconian
Rhyolite
. The rhyolitic rocks themselves are representative of explosive volcanic centres to the west of this site and beyond the Church Stretton
lineament.
There is a clear distinction between the tuffaceous rocks of the Uriconican Volcanics (dark brown/black/grey) and the intrusive granophyre
which is pink. The relationship between the Ercall Granophyre and the Uriconian is also clearly evident as the Granophyre intrudes the Volcanic rocks and is therefore younger.
The Ercall Granophyre is overlain by shallow dipping Cambrian
rocks (in relation to the steeply dipping Uriconian
volcanics) which contain Atdabanian fossils. The Granophyre
is dated at 560+/-1Ma and is thought to be related to the volcanic events in the area. The thermal expansion of the area is likely to have assisted the formation of a sedimentary basin in which such volcaniclastic sediments accrued and were later folded. This has given rise to the steeply dipping sequences exposed at places such as the Forest Glen car park. The folding event is thought to be contemporaneous with uplift and a date of 526+/-28Ma has been put forward for this.
Ceremonial counties of England
The ceremonial counties are areas of England to which are appointed a Lord Lieutenant, and are defined by the government as counties and areas for the purposes of the Lieutenancies Act 1997 with reference to the metropolitan and non-metropolitan counties of England and Lieutenancies Act 1997...
of Shropshire
Shropshire
Shropshire is a county in the West Midlands region of England. For Eurostat purposes, the county is a NUTS 3 region and is one of four counties or unitary districts that comprise the "Shropshire and Staffordshire" NUTS 2 region. It borders Wales to the west...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. It is located between The Wrekin
The Wrekin
The Wrekin is a hill in east Shropshire, England. It is located some west of Telford, on the border between the unitary authorities of Shropshire and Telford and Wrekin. Rising to a height of above the Shropshire Plain, it is a prominent and well-known landmark, marking the entrance to Shropshire...
and Wellington
Wellington, Shropshire
Wellington is a town in the unitary authority of Telford and Wrekin and ceremonial county of Shropshire, England and now forms part of the new town of Telford. The population of the parish of Wellington was recorded as 20,430 in the 2001 census, making it the third largest town in Shropshire if...
, in the Telford & Wrekin borough. It is regarded as an internationally important geological site, which is part of The Wrekin and The Ercall Site of Special Scientific Interest (SSSI). The hill is managed by Shropshire Wildlife Trust
Shropshire Wildlife Trust
The Shropshire Wildlife Trust is a wildlife trust covering the geographic county of Shropshire, England.-Nature reserves:The trust cares for, or is associated with, 42 nature reserves in the county:...
. The site includes 540 million year old ripple beds and ancient pre-Cambrian lava flows in exposed quarries. http://www.shropshirewildlifetrust.org.uk/wp_22_ercall.html Quartzite
Quartzite
Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...
from the neighbouring Wrekin is also visible. The Ercall bears the marks of extensive quarrying, although the quarries are now disused, safe and open to the public. When the M54 motorway
M54 motorway
The M54 is a 23 mile east-west motorway in the English counties of Shropshire and Staffordshire. It is also referred to as the Telford Motorway, after the road's primary westbound destination, the new town of Telford...
was constructed in 1974, the road was built through the northern end of the hill.
Flora and fauna
The woods of the forest are important for various butterflyButterfly
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...
species. In the summer, the Ercall Woods which line the hill are a favourite habitat for the Speckled Wood
Speckled Wood
The Speckled Wood is a butterfly found in and on the borders of woodland throughout much of the Palearctic ecozone.In North Europe, Central Europe , Asia Minor, Syria, Russia and Central Asia where subspecies P. a. tircis occurs it is brown with pale yellow or cream spots and darker upperwing...
and during spring when the forest is laden with bluebells
Common Bluebell
Hyacinthoides non-scripta, commonly known as the common bluebell, is a spring-flowering bulbous perennial plant. -Taxonomy:...
, the Dingy Skipper
Dingy Skipper
The Dingy Skipper, Erynnis tages, is a butterfly of the Hesperiidae family. It ranges from Europe across Asia Minor and Central Asia to the Amur region.Erynnis tages favours open grassy habitats up to 2,000 metres above sea level...
can arrive in great numbers. The exposed quarries are popular with other butterfly species, including the Green Hairstreak
Green Hairstreak
The Green Hairstreak, Callophrys rubi, is a butterfly in the family Lycaenidae.Callophrys rubi is found in Europe, North Africa, Russia, Asia Minor, Siberia, Amurland , Baluchistan and Chitral....
and Wall, which like to bask in sheltered spots.
On the upper slopes of the hill tall oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
trees predominate. Acidic soils support such plants as bilberry
Bilberry
Bilberry is any of several species of low-growing shrubs in the genus Vaccinium , bearing edible berries. The species most often referred to is Vaccinium myrtillus L., but there are several other closely related species....
, climbing corydalis
Corydalis
Corydalis is a genus of about 470 species of annual and perennial herbaceous plants in the fumewort family , native to the temperate Northern Hemisphere and the high mountains of tropical eastern Africa...
and heath bedstraw. The Green woodpecker
Green Woodpecker
The European Green Woodpecker is a member of the woodpecker family Picidae. There are four subspecies and it occurs in most parts of Europe and in western Asia...
is also present in the woods.http://www.shropshirewildlifetrust.org.uk/pdfs/ercall_walks.pdf
Access
The hill is accessed in much the same way as The WrekinThe Wrekin
The Wrekin is a hill in east Shropshire, England. It is located some west of Telford, on the border between the unitary authorities of Shropshire and Telford and Wrekin. Rising to a height of above the Shropshire Plain, it is a prominent and well-known landmark, marking the entrance to Shropshire...
nearby; exit the M54 motorway
M54 motorway
The M54 is a 23 mile east-west motorway in the English counties of Shropshire and Staffordshire. It is also referred to as the Telford Motorway, after the road's primary westbound destination, the new town of Telford...
at J7 (last exit) or the last junction of the A5 from Shrewsbury
Shrewsbury
Shrewsbury is the county town of Shropshire, in the West Midlands region of England. Lying on the River Severn, it is a civil parish home to some 70,000 inhabitants, and is the primary settlement and headquarters of Shropshire Council...
before it becomes the M54. From there The Wrekin is signposted; follow this road until you reach The Wrekin, then follow the sign for the Buckatree Hotel. There is a small car park across the road from this pub/hotel, and the entrance is clearly visible.
Geology
The Ercall Quarries are a SSSI and therefore care needs to be exercised when investigating this area. Upon entering the quarry from the main entrance near The WrekinThe Wrekin
The Wrekin is a hill in east Shropshire, England. It is located some west of Telford, on the border between the unitary authorities of Shropshire and Telford and Wrekin. Rising to a height of above the Shropshire Plain, it is a prominent and well-known landmark, marking the entrance to Shropshire...
one encounters an old quarry with many distinctive geological features evident. http://www.shropshiregeology.org.uk
This is the first quarry that is apparent in the Ercall, it comprises Uriconian
Uriconian
The Uriconian rocks of Shropshire are thought to be potentially related to the Longmyndian Supergroup of the Stretton Hills, Shropshire, United Kingdom. Current geological profiling of the terranes suggests that the Uriconian rocks are of Precambrian age...
Volcanic deposits of Precambrian
Precambrian
The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...
age. Such volcanic deposits are noted to have been bimodal and potentially intraplate possibly induced by (and therefore close to a) subduction zone and possibly in an island arc setting. The flow banding and fine to medium grained appearance of the deposit suggests a fairly rapid cooling event and appears to have been deposited in a submerged environment. In all likelihood, during such events the depositional environment would fluctuate between submarine and subaerial as sea-floor levels will have fluctuated as well as eustatic sea-levels.
On the right had side of the picture (running vertical) a dark grey doleritic dyke is evident. The dyke trends at approximately 65 degrees. Dolerite is intrusive and is relative to basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...
(extrusive). There is a significant alteration about the contact between the two rocks. The dolerite dyke was emplaced into the Uriconian
Uriconian
The Uriconian rocks of Shropshire are thought to be potentially related to the Longmyndian Supergroup of the Stretton Hills, Shropshire, United Kingdom. Current geological profiling of the terranes suggests that the Uriconian rocks are of Precambrian age...
Rhyolite
Rhyolite
This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...
. The rhyolitic rocks themselves are representative of explosive volcanic centres to the west of this site and beyond the Church Stretton
Church Stretton
Church Stretton is a small town and civil parish in Shropshire, England. The population of the town was recorded as 2,789 in 2001, whilst the population of the wider parish was recorded as 4,186...
lineament.
There is a clear distinction between the tuffaceous rocks of the Uriconican Volcanics (dark brown/black/grey) and the intrusive granophyre
Granophyre
Granophyre is a subvolcanic rock that contains quartz and alkali feldspar in characteristic angular intergrowths such as those in the accompanying image....
which is pink. The relationship between the Ercall Granophyre and the Uriconian is also clearly evident as the Granophyre intrudes the Volcanic rocks and is therefore younger.
The Ercall Granophyre is overlain by shallow dipping Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
rocks (in relation to the steeply dipping Uriconian
Uriconian
The Uriconian rocks of Shropshire are thought to be potentially related to the Longmyndian Supergroup of the Stretton Hills, Shropshire, United Kingdom. Current geological profiling of the terranes suggests that the Uriconian rocks are of Precambrian age...
volcanics) which contain Atdabanian fossils. The Granophyre
Granophyre
Granophyre is a subvolcanic rock that contains quartz and alkali feldspar in characteristic angular intergrowths such as those in the accompanying image....
is dated at 560+/-1Ma and is thought to be related to the volcanic events in the area. The thermal expansion of the area is likely to have assisted the formation of a sedimentary basin in which such volcaniclastic sediments accrued and were later folded. This has given rise to the steeply dipping sequences exposed at places such as the Forest Glen car park. The folding event is thought to be contemporaneous with uplift and a date of 526+/-28Ma has been put forward for this.