The Green Bridge of Wales (Welsh : Pont Werdd Cymru) is a natural arch formed from Carboniferous Limestone within the Pembrokeshire Coast National Park, Pembrokeshire, Wales. It is located in the Castlemartin military training area just beyond the car park at Stack Rocks (Creigiau Elegig) and beside the Pembrokeshire Coast Path. [1]
The geology of the area in which the Green Bridge of Wales is located is composed of a very thick layer of Carboniferous Limestone, including a certain amount of chert. Erosion has occurred over time as storm winds have battered the coast, pebbles have been dashed against the rocks, sand particles have worn away the surface, and chemical erosion has dissolved the limestone. The weakest parts of the cliff are the first to be worn away, usually the folds and small faults that are present in the rocks. This has resulted over many millennia in the creation of many unusual landforms. In the case of the Green Bridge of Wales, erosion has taken place on both sides of a small headland, caves have been formed which extended further and further until they met, forming the arch that can be seen today. The bridge is about 24 m (80 ft) high with a span of more than 20 m (66 ft). Its outer edge rests on a more durable rock pedestal and its upper surface is clad in vegetation. [2] The Green Bridge lost a considerable amount of rock to damage during Storm Ophelia in October 2017. [3]
Like the nearby Elegug Stacks and Huntsman's Leap further to the east it is a popular visitor attraction and can be accessed by walkers from the Pembrokeshire Coast Path. Images of it appear frequently both in tourism publications and in geography textbooks. With a height of around 80 ft, the Natural Arch and Bridge Society describe it as 'probably the most spectacular arch in the United Kingdom'. [4]
The site lies at the extreme west of the eastern sector of the Ministry of Defence's Castlemartin military training area but access for the public is normally available. [1]
A natural arch, natural bridge, or rock arch is a natural landform where an arch has formed with an opening underneath. Natural arches commonly form where inland cliffs, coastal cliffs, fins or stacks are subject to erosion from the sea, rivers or weathering.
The Pembrokeshire Coast Path, often called the Pembrokeshire Coastal Path, is a designated National Trail in Pembrokeshire, southwest Wales. Established in 1970, it is a 186-mile (299 km) long-distance walking route, mostly at cliff-top level, with a total of 35,000 feet (11,000 m) of ascent and descent. At its highest point – Pen yr afr, on Cemaes Head – it reaches a height of 574 feet (175 m), and at its lowest point – Sandy Haven crossing, near Milford Haven – it is just 6 feet (2 m) above low water. Whilst most of the coastline faces west, it offers – at varying points – coastal views in every direction of the compass.
A stack or sea stack is a geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast, formed by wave erosion. Stacks are formed over time by wind and water, processes of coastal geomorphology. They are formed when part of a headland is eroded by hydraulic action, which is the force of the sea or water crashing against the rock. The force of the water weakens cracks in the headland, causing them to later collapse, forming free-standing stacks and even a small island. Without the constant presence of water, stacks also form when a natural arch collapses under gravity, due to sub-aerial processes like wind erosion. Erosion causes the arch to collapse, leaving the pillar of hard rock standing away from the coast—the stack. Eventually, erosion will cause the stack to collapse, leaving a stump. Stacks can provide important nesting locations for seabirds, and many are popular for rock climbing.
Durdle Door is a natural limestone arch on the Jurassic Coast near Lulworth in Dorset, England. It is privately owned by the Weld family, who own the Lulworth Estate, but it is also open to the public.
Pembrokeshire Coast National Park is a national park along the Pembrokeshire coast in west Wales.
Ogmore-by-Sea is a seaside village in St Brides Major community in the Vale of Glamorgan, Wales. It lies on the western limit of the Glamorgan Heritage Coast of south Wales. The population in 2011 was 878.
The Stackpole Estate is located between the villages of Stackpole and Bosherston in Pembrokeshire, Wales, within the Pembrokeshire Coast National Park. It is situated within the community of Stackpole and Castlemartin.
Carboniferous Limestone is a collective term for the succession of limestones occurring widely throughout Great Britain and Ireland that were deposited during the Dinantian Epoch of the Carboniferous Period. These rocks formed between 363 and 325 million years ago. Within England and Wales, the entire limestone succession, which includes subordinate mudstones and some thin sandstones, is known as the Carboniferous Limestone Supergroup.
Southerndown is a village in the Vale of Glamorgan, in south Wales. It is southwest of Bridgend, and within the St Brides Major community, close to Llantwit Major and Ogmore-by-Sea. It is mostly known for its beach which backs Dunraven Bay, which is a popular tourist destination during the summer months and since 1972 has been part of a Heritage Coast and is part of the Southerndown Coast SSSI. When the tide is out there is an expanse of sand and pools. The cliffs are an obvious example of sedimentary rock.
South Wales is an area with many features of outstanding interest to geologists, who have for long used the area for University field trips.
Barafundle Bay is a remote, slightly curved, east-facing sandy beach, near Stackpole Quay in Pembrokeshire, Wales, in Stackpole and Castlemartin Community. It is part of the Stackpole Estate, managed by The National Trust. The beach was once owned by the Cawdor family of Stackpole Court. On the northern approach to the beach are steps and a wall, which were built by the owners to ease their access to what was then their private beach.
The geology of Wales is complex and varied; its study has been of considerable historical significance in the development of geology as a science. All geological periods from the Cryogenian to the Jurassic are represented at outcrop, whilst younger sedimentary rocks occur beneath the seas immediately off the Welsh coast. The effects of two mountain-building episodes have left their mark in the faulting and folding of much of the Palaeozoic rock sequence. Superficial deposits and landforms created during the present Quaternary period by water and ice are also plentiful and contribute to a remarkably diverse landscape of mountains, hills and coastal plains.
Castlemartin is a village and parish in the community of Stackpole and Castlemartin, Pembrokeshire, Wales, in the Pembrokeshire Coast National Park.
Castlemartin Training Area is a British Army military training area and armoured fighting vehicle range located in the Welsh county of Pembrokeshire. It was originally established for tank training by the Royal Armoured Corps in 1938. The training area is located within the Pembrokeshire Coast National Park, on the South Pembrokeshire coast.
Southerndown Coast is a Site of Special Scientific Interest (SSSI) in St Brides Major community, in the Vale of Glamorgan, South Wales. It forms part of the Glamorgan Heritage Coast, bordered by the Monknash Coast to the southeast. The nearby villages are Southerndown and Ogmore-by-Sea. The SSSI extends over 5 kilometres of south-west facing coastline, with rocky limestone cliffs, broad beaches and deeply fissured wave-cut platforms.
Stackpole and Castlemartin is a community in Pembrokeshire, Wales, 4 miles (6.4 km) south of Pembroke.
Huntsman's Leap is a deep, narrow and sheer-sided coastal chasm or geo developed in the Carboniferous Limestone of the Pembrokeshire Coast National Park, Pembrokeshire, Wales. Like the nearby Green Bridge of Wales and St Govan's Chapel, it is a popular visitor attraction which lies beside the Pembrokeshire Coast Path. The site lies within the eastern sector of the Ministry of Defence's Castlemartin military training area, but access for the public is normally available.
The geology of the Gower Peninsula in South Wales is central to the area's character and to its appeal to visitors. The peninsula is formed almost entirely from a faulted and folded sequence of Carboniferous rocks though both the earlier Old Red Sandstone and later New Red Sandstone are also present. Gower lay on the southern margin of the last ice sheet and has been a focus of interest for researchers and students in that respect too. Cave development and the use of some for early human occupation is a further significant aspect of the peninsula's scientific and cultural interest.
The coastline of Wales extends from the English border at Chepstow westwards to Pembrokeshire then north to Anglesey and back eastwards to the English border once again near Flint. Its character is determined by multiple factors, including the local geology and geological processes active during and subsequent to the last ice age, its relative exposure to or shelter from waves, tidal variation and the history of human settlement and development which varies considerably from one place to another. The majority of the coast east of Cardiff in the south, and of Llandudno in the north, is flat whilst that to the west is more typically backed by cliffs. The cliffs are a mix of sandstones, shales and limestones, the erosion of which provides material for beach deposits. Of the twenty-two principal areas which deliver local government in Wales, sixteen have a coastline, though that of Powys consists only of a short section of tidal river some distance from the open sea. Its length has been estimated at 1,680 miles (2,700 km).
The geology of Pembrokeshire in Wales inevitably includes the geology of the Pembrokeshire Coast National Park which extends around the larger part of the county's coastline and where the majority of rock outcrops are to be seen. Pembrokeshire's bedrock geology is largely formed from a sequence of sedimentary and igneous rocks originating during the late Precambrian and the Palaeozoic era, namely the Ediacaran, Cambrian, Ordovician, Silurian, Devonian and Carboniferous periods, i.e. between 635 and 299 Ma. The older rocks in the north of the county display patterns of faulting and folding associated with the Caledonian Orogeny. On the other hand, the late Palaeozoic rocks to the south owe their fold patterns and deformation to the later Variscan Orogeny.