North Dock Tufa
Encyclopedia
The North Dock Tufa is a small dome-shaped petrified well, with stalactites and stalagmites, tucked away behind the Marine Activities Centre at Sunderland marina
. It is notable for being the best example of its kind in the North of England.
began work on developing Sunderland marina. Geologists from Sunderland Museum and Sunderland University were called in to take a look and identified it as a “calcareous
tufa dome.”
Tufa is the name given by geologist
s to deposits of calcium carbonate
, a chemical compound which is a common ingredient of seashell
s, eggshells and rock. The water which flows through the North Dock Tufa is full of dissolved calcite
– a mineral which makes up calcium carbonate.
The Tufa built up over several decades as the calcite water covered roots and grasses, forming stalactites and stalagmites. Eventually, everything became petrified. The wall to which the Tufu is attached is part of the original North Dock, which was opened in 1837, so it can only date back to this time.
The water trickling through the Tufa has been traced to just below Harbour View Road, where it can be seen to seep out of the ground. No-one, however, has yet discovered where this water is coming from. Geologists believe it must be filtering through the local Permian Limestone
, picking up calcium carbonate along its route. It is possible that this process starts as far away as Fulwell Quarries, which is two miles away.
It is thought that the water could be channelled here through a buried valley
, or by the original route of the old railway line, which used to enter the dock at about this point. To preserve the Tufa, the design of the Marine Activities Centre was modified and conservation began at the site in 1993.
The conservation work included removing material from the base of the dome, to make way for a concrete foundation. Bore holes were made through the back of the formation, and steel rods - known as stitch anchors - were placed in the holes, to support the Tufa and stop it coming away from the wall. The Marine Centre was then built around the Tufa.
In 1995 the North Dock Tufa was designated as a Regionally Important Geological Site
by Sunderland Council. It was the first such site in Tyne and Wear
to receive this status. Today the Tufa, which is still growing and becoming heavier each year, is used by geologists for teaching purposes.
Marina
A marina is a dock or basin with moorings and supplies for yachts and small boats.A marina differs from a port in that a marina does not handle large passenger ships or cargo from freighters....
. It is notable for being the best example of its kind in the North of England.
History of the Tufa
The North Dock Tufa was discovered behind some old huts in 1992, when Tyne and Wear Development CorporationTyne and Wear Development Corporation
The Tyne and Wear Development Corporation was established in 1987 to develop land on the banks of the River Tyne and the River Wear in England. Its flagship developments included the regeneration of the East Quayside in Newcastle, Royal Quays in North Tyneside and St Peter's in Sunderland. During...
began work on developing Sunderland marina. Geologists from Sunderland Museum and Sunderland University were called in to take a look and identified it as a “calcareous
Calcareous
Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.-In zoology:...
tufa dome.”
Tufa is the name given by geologist
Geologist
A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that has shaped it. Geologists usually engage in studying geology. Geologists, studying more of an applied science than a theoretical one, must approach Geology using...
s to deposits of calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
, a chemical compound which is a common ingredient of seashell
Seashell
A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer created by an animal that lives in the sea. The shell is part of the body of the animal. Empty seashells are often found washed up on beaches by beachcombers...
s, eggshells and rock. The water which flows through the North Dock Tufa is full of dissolved calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
– a mineral which makes up calcium carbonate.
The Tufa built up over several decades as the calcite water covered roots and grasses, forming stalactites and stalagmites. Eventually, everything became petrified. The wall to which the Tufu is attached is part of the original North Dock, which was opened in 1837, so it can only date back to this time.
The water trickling through the Tufa has been traced to just below Harbour View Road, where it can be seen to seep out of the ground. No-one, however, has yet discovered where this water is coming from. Geologists believe it must be filtering through the local Permian Limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
, picking up calcium carbonate along its route. It is possible that this process starts as far away as Fulwell Quarries, which is two miles away.
It is thought that the water could be channelled here through a buried valley
Buried valley
A buried valley is an ancient river or stream valley that since has been filled with glacial or unconsolidated sediment. This sediment is made up of gravel, sand, silt, and clay. These types of sediment can often store and transmit large amounts of ground water....
, or by the original route of the old railway line, which used to enter the dock at about this point. To preserve the Tufa, the design of the Marine Activities Centre was modified and conservation began at the site in 1993.
The conservation work included removing material from the base of the dome, to make way for a concrete foundation. Bore holes were made through the back of the formation, and steel rods - known as stitch anchors - were placed in the holes, to support the Tufa and stop it coming away from the wall. The Marine Centre was then built around the Tufa.
In 1995 the North Dock Tufa was designated as a Regionally Important Geological Site
Regionally Important Geological Site
Regionally Important Geological and Geomorphological Sites are locally designated sites of local, national and regional importance for geodiversity in the United Kingdom. RIGS may be designated for their value to Earth Science, and to Earth heritage in general, and may include cultural,...
by Sunderland Council. It was the first such site in Tyne and Wear
Tyne and Wear
Tyne and Wear is a metropolitan county in north east England around the mouths of the Rivers Tyne and Wear. It came into existence as a metropolitan county in 1974 after the passage of the Local Government Act 1972...
to receive this status. Today the Tufa, which is still growing and becoming heavier each year, is used by geologists for teaching purposes.