Cow Green Geotrail

1:50 000 Geological Sheet 31 Brough-under-Stainmore 31 Sheet Geological 000 1:50

1:50 000 Geological Sheet 25 Alston 25 Sheet Geological 000 1:50

walk you will see evidence of mining for barium minerals. barium for mining of evidence see will you walk

the cracks, building up mineral veins and deposits. On this this On deposits. and veins mineral up building cracks, the Middleton-in-Teesdale

deposition of material elsewhere. material of deposition

cooled, their dissolved minerals crystallised on the walls of of walls the on crystallised minerals dissolved their cooled, 1:25 000 Geological Sheet NY82 and part of NY92 NY92 of part and NY82 Sheet Geological 000 1:25

both through continued erosion of the hills, and through through and hills, the of erosion continued through both

magma known as the old Weardale Granite. As the ﬂ uids uids ﬂ the As Granite. Weardale old the as known magma

British Geological Survey Geological British

Water continues to shape the North Pennines today, today, Pennines North the shape to continues Water old buried intrusion of of intrusion buried old

landscape, littered with the evidence of this glacial period. period. glacial this of evidence the with littered landscape, and Weardale and Granite by a 400 million year year million 400 a by

Weardale The effects of ice and water have left behind a scarred scarred a behind left have water and ice of effects The 1:25 000 Explorer OL31 North Pennines Teesdale Teesdale Pennines North OL31 Explorer 000 1:25 Slate solutions were heated heated were solutions

Pennines to form the rugged landscape we see today. today. see we landscape rugged the form to Pennines underground. These These underground. Ordnance Survey Ordnance

valleys of the North North the of valleys in the rocks deep deep rocks the in

Useful maps: Useful

modiﬁ ed the hills and and hills the ed modiﬁ through cracks cracks through

on 0871 200 2233 (www.traveline.info) 2233 200 0871 on across the land it it land the across rich waters ﬂ owing owing ﬂ waters rich

For timetable information call Traveline Traveline call information timetable For transport: Public As the ice crawled crawled ice the As ago, from mineral- from ago,

the start of this walk. walk. this of start the 290 million years years million 290

of Upper Teesdale can be harsh and unpredictable. unpredictable. and harsh be can Teesdale Upper of

Mineral veins Mineral

which can be seen from from seen be can which These formed about about formed These waterproofs are advised, as even in summer the weather weather the summer in even as advised, are waterproofs

mineral deposits. deposits. mineral area, like Cross Fell, Fell, Cross like area,

surface excavations. Stout boots, warm clothing and good good and clothing warm boots, Stout excavations. surface Shale

is famous for its its for famous is highest peaks in the the in peaks highest

the footpaths and do not attempt to enter old tunnels or or tunnels old enter to attempt not do and footpaths the

Sandstone

The North Pennines Pennines North The spread out from the the from out spread workings, parts of which may be unstable. Please keep to to keep Please unstable. be may which of parts workings,

The ice originated and and originated ice The

to the car park. In places the route passes old mine mine old passes route the places In park. car the to Limestone

Buried treasure Buried

several kilometres thick. thick. kilometres several this, turn around at the top of the waterfall and return return and waterfall the of top the at around turn this,

bottom of Cauldron Snout. If you do not want to negotiate negotiate to want not do you If Snout. Cauldron of bottom a vast ice sheet up to to up sheet ice vast a

roads. At stop stop At roads. there is a steep scramble to reach the the reach to scramble steep a is there

ancient sediment. ancient Europe, was beneath beneath was Europe, 8

This trail uses well-marked footpaths and minor minor and footpaths well-marked uses trail This Terrain: are formed from from formed are with much of northern northern of much with

rocks, because they they because rocks, North Pennines, along along Pennines, North

NY 811 309 811 NY

known as ‘sedimentary’ ‘sedimentary’ as known

20,000 years ago the the ago years 20,000

Limestone Grid reference: Grid Global Geopark Global

Rocks of this kind are are kind this of Rocks

AONB & UNESCO & AONB

Ice Age legacy Age Ice

(Cow Green Reservoir) Green (Cow the rocks we see today. today. see we rocks the North Pennines North

Wheelhead Sike car park park car Sike Wheelhead deltas hardened into into hardened deltas

Park at at Park nish: Start/ﬁ tropical seas and river river and seas tropical

surface in several places. several in surface

in Teesdale in

ooze, sand and mud in in mud and sand ooze,

Middleton - Middleton

Walk start Walk to the Cow Green road. Green Cow the to

of years of erosion the Whin Sill is now exposed at the the at exposed now is Sill Whin the erosion of years of

Shale the equator. Limey Limey equator. the

past Widdy Bank Farm Farm Bank Widdy past

called dolerite (known locally as whinstone). After millions millions After whinstone). as locally (known dolerite called

Pennines lay close to to close lay Pennines

be made by continuing continuing by made be Stanhope

vast, roughly horizontal sheet of a hard, dark, igneous rock rock igneous dark, hard, a of sheet horizontal roughly vast,

become the North North the become Alston

(12km) circular route can can route circular (12km)

cooled and solidiﬁ ed underground to form the Whin Sill, a a Sill, Whin the form to underground ed solidiﬁ and cooled

the area that was to to was that area the

8km (5 miles). A longer longer A miles). (5 8km

the layers of older rocks. It It rocks. older of layers the

300 million years ago, ago, years million 300 Approx. Approx. length: Walk

up and spread out between between out spread and up

Between 360 and and 360 Between

Hexham

Feeder Dyke

rock at over 1000°C to rise rise to 1000°C over at rock the local landscape. landscape. local the

Sandstone

years ago caused molten molten caused ago years

have a big impact on on impact big a have

the River Tees to form a satisfying circular route. route. circular satisfying a form to Tees River the

crust around 295 million million 295 around crust

parts of this trail and and trail this of parts

Whin Sill Whin

the steep descent by Cauldron Snout, or extended further down down further extended or Snout, Cauldron by descent steep the Coal

Stretching of the Earth’s Earth’s the of Stretching be clearly seen along along seen clearly be

11 points of interest along a set route. It can be cut short to avoid avoid to short cut be can It route. set a along interest of points 11

you will see on this walk. walk. this on see will you Layers of limestone can can limestone of Layers

dale a haven for rare and interesting plants. The trail identiﬁ es es identiﬁ trail The plants. interesting and rare for haven a dale

in Upper Teesdale, as as Teesdale, Upper in sandstone and shale. shale. and sandstone

so special for scientists, visitors and industry, and which make the the make which and industry, and visitors scientists, for special so

forms dramatic landscapes landscapes dramatic forms beds of limestone, limestone, of beds

many of the rocks that have made the Upper Teesdale landscape landscape Teesdale Upper the made have that rocks the of many

Limestone

regular alternating alternating regular of the North Pennines and and Pennines North the of

This linear trail starts beside Cow Green Reservoir and introduces introduces and Reservoir Green Cow beside starts trail linear This

Pennines consists of of consists Pennines special geological features features geological special Shale

and thousands of years of human activity. human of years of thousands and

Much of the North North the of Much The Whin Sill is one of the the of one is Sill Whin The Sandstone

...shaped by millions of years of natural processes processes natural of years of millions by ...shaped

Limestone Limestone, sandstone and shale and sandstone Limestone, The Whin Sill Whin The Welcome to a special landscape... special a to Welcome

Cow Green is in the North Pennines Area of Outstanding Natural Beauty (AONB) and UNESCO The North Pennines Area of Outstanding Natural Beauty Cow Green Global Geopark. (AONB) is one of England’s most special places – a stunning, upland landscape of wide open moors, What is a UNESCO Global Geopark? Geotrail ﬂ ower-rich hay meadows, intimate woods, dark night The North Pennines AONB is a UNESCO Global skies, charismatic wildlife, industrial heritage, tumbling Geopark. Geoparks are places with outstanding rivers and dramatic waterfalls. In recognition of its Layers and landscapes geology and landscape, where there are strong local world class Earth heritage and efforts to make the efforts to make the most of Earth heritage through interpretation, education, conservation and tourism. most of this for tourism and education, it is also To ﬁ nd out more visit www.europeangeoparks.org designated as a UNESCO Global Geopark. and www.globalgeopark.org

Find out more about North Pennine geology An 8km (5 mile) walk exploring the spectacular landscape and rocks around Cow Green Reservoir and This leaﬂ et is one of a series of geological trails and Cauldron Snout in Upper Teesdale. publications for the North Pennines. To discover the others and to ﬁ nd out more about our geological heritage, visit www.northpennines.org.uk North Pennines AONB Partnership NorthPenninesAONB www.northpennines.org.uk @NorthPennAONB Moor House-Upper Teesdale National Nature Reserve (NNR) +44 (0)1388 528801 northpennines [email protected] This trail is within the Moor House-Upper Teesdale northpenninesaonb NNR. This large reserve contains an almost complete range of upland habitats typical of the North Pennines, from hay meadows and juniper woods to limestone grassland and blanket bog. For more information contact the reserve base on 01833 622374.

This publication is based on original work by the North Pennines AONB Partnership and British Geological Survey, with thanks given to members of the AONB Partnership’s Geopark Advisory Group for their expertise and input.

North Pennines - Cow Green Geotrail (NF) 2.indd 1 19/08/2019 16:42 Outer Spread 1 Car park viewpoint Follow the road Turn right onto the footpath The road dips and crosses a small Far to the west are(from for around 150m just after this exposure, stream. Just before the top of the left to right) the peaks of south-east to a then turn left where this next rise, look for a shallow trench Great Dun Fell, Little Dun patch of grey joins the single track road on the left. This marks the line of a Fell and Cross Fell. Their rock on the right. to Cauldron Snout. mineral vein, known as Rod’s Vein. distinctive shapes refl ect the almost horizontal layers of sandstone, limestone and shale of which they are formed. Also note the mine entrances on the hillside above the car park. 1 P 2 Tropical seas 2 START 3 The rock exposed here is the Smiddy Limestone. Look for small, white fragments of 4 Continue down shell and crinoids the road, stopping (creatures related at points 5 , 6 and to sea urchins and 7 as indicated on starfi sh) fossilised the map. within the grey Pennine Way limestone. The slightly Widdybank raised part of the Widdybank Fell Farm outcrop furthest from Cow Green the road is a mound Reservoir’ made of corals known as a bioherm. It formed around 330 5 million years ago when the North Pennines sat beneath a shallow, tropical sea. Red Sike Cronkley 6 Scar Just before the bridge, 3 Layers in the rocks turn left off the road and Looking back from the gate an outcrop of the Peghorn follow the Pennine Way Limestone is visible. The narrow area of ground beneath 7 National Trail to the top the outcrop is formed from beds of sandstone and shale. of Cauldron Snout. As you continue through the gate and along the road, notice the sharp contrast between green grass on the 8 N limestones and heather on the sandstones and shales. 9 Falcon Clints 4 Rod’s Vein Pennine 10 Way Optional route Veins are vertical bands extension of mineral that fi ll up 11 fi ssures and faults within Maize 1 km Beck the surrounding rocks. River Tees The old spoil heaps scale contain fragments of the white mineral baryte (barium sulphate) that Follow the very steep footpath down This is the end of the trail. You now have the was mined here. There the side of Cauldron Snout, taking option of turning around and retracing your are also traces of galena, particular care on the rocks, which steps to the car park (approximately 4km) or the main ore of lead. are often slippery. Alternatively, you continuing along the Pennine Way until you Although the veins at Cow can view parts of the next stop from reach Widdy Bank Farm,WhinWhin followingSill Sill the track to Green did not contain enough lead for it to be worth the top, before retracing your steps the Cow Green road, then following the road mining on a commercial scale, baryte was mined here until back to the car park. (left) back to the car park (approximately 7km). 1952 for use in the paint and chemical industries.

5 Sugar limestone The outcrops of rock, Whin Sill most noticeable to the left of the road, are of the Melmerby Scar Limestone. These rocks are white and crystalline and Limestone show a distinctive crumbly weathering, earning them the local name ‘sugar limestone’. Despite its name, the sugar limestone is actually a type of marble, having been altered and recrystallised by intense heat. Such rocks are called metamorphic rocks. 10 Falcon Clints 8 Top of Cauldron Snout Between Cauldron Snout and Widdy Bank Farm the 6 The Great Whin Sill The waterfall at Cauldron Snout is formed as the River river fl ows in a steep-sided valley cut through the Whin Sill on the left. Downstream from the waterfall more The rusty brown rocks in Tees fl ows across a very hard outcrop of the Whin Sill marble (sugar limestone) may be seen beneath the dark the stream at Red Sike are part of the dolerite. Notice the vertical cracks in the rock, which are grey crags of the Whin Sill. Notice the striking vertical Whin Sill (see overleaf). Here in Upper Teesdale known as columnar joints. They formed as the magma contracted during the fi nal stages of cooling. This is columns of dolerite in the cliffs on Falcon Clints, and this layer is almost 75 metres thick. The molten rock that similar to the formation of the famous columns at the further downstream on Cronkley Scar. From Red Sike cooled to become the dolerite of the Whin Sill baked Giant’s Causeway in Northern Ireland and Fingal’s Cave (stop ) to here, you have travelled the full depth the surrounding rocks, creating the sugar limestone in Scotland, although the Whin Sill is considerably older of the Whin Sill. you saw earlier. at 295 million years. 11 7 Conglomerates Cow Green Dam 9 Foot of Cauldron Snout The footpath here crosses small outcrops of a darker, As you round the corner to the front of the dam, The Whin Sill dolerite forms both the lip of the rubbly-looking rock known as a conglomerate. It is notice how it is built in two parts. The closer part waterfall and many small craggy made up of pebbles of older rocks set in mud. These is a solid concrete wall built on the hard Whin outcrops on both banks of the river. older rocks are exposed on the south bank of the river Sill, while the The smooth, grassy western bank at Pencil Mill, about 1km east of Widdy Bank Farm. far side is an Pre-glacial river channel is the old channel of the River Tees, The conglomerate itself dates back to early in the earth bank dating back to before the last glacial Carboniferous Period (around built where period, which began around 115,000 350 million years ago) when the dam years ago. The old valley fi lled up an ancient mountain chain crosses what with boulder clay deposited by the was being eroded. Over time was once the ice. When the ice melted and the river the sea level rose, and the river channel, began to fl ow again it was diverted conglomerate was buried now fi lled with and cut a new channel through the beneath layers of limestone, boulder clay. hard dolerite. shale and sandstone.

North Pennines - Cow Green Geotrail (NF) 2.indd 2 19/08/2019 16:42 Inner Spread