Brisbane tuff is a type of rock, formed as a result of a volcanic eruption. As the name suggests, it is a type of

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock ...

found in

Brisbane Brisbane ( ) is the capital and most populous city of the Australian state of Queensland, and the third-most populous city in Australia and Oceania, with a population of approximately 2.6 million. Brisbane lies at the centre of the South ...

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , establishe ...

, Australia. It is a form of welded ignimbrite. Brisbane tuff comes in a variety of colours: pink, green, blue (grey) and purple. The different colours are due to the extent of oxidation of iron and

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

. It is often incorrectly described as porphyry.

History

Brisbane tuff began to be used during the period when Captain

Patrick Logan Captain Patrick Logan (1791 – October 1830) was the commandant of the Moreton Bay Penal Settlement from 1826 until his death in 1830 at the hands of Aboriginal Australians who objected to him entering their lands. As he had been hated by co ...

was the commandant of the

Moreton Bay penal colony The Moreton Bay Penal Settlement operated from 1825 to 1842. It became the city of Brisbane, Queensland, Australia. History The Moreton Bay Penal Settlement was established on the Redcliffe Peninsula on Moreton Bay in 1824, under the instruct ...

. Brisbane tuff is found in various parts of Brisbane and was quarried extensively in the early history of Brisbane at the

Kangaroo Point Cliffs The Kangaroo Point Cliffs are heritage-listed cliffs located at Kangaroo Point just across the Brisbane River from the Brisbane CBD in Queensland, Australia. A popular recreation spot, especially for climbing and running, they are convenient ...

and the (now) Windsor Town Quarry Park for use in construction of Brisbane's earliest buildings.

Geology

Brisbane tuff was formed by the welding and compaction of

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, created during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to refer ...

more than 226 million years ago. It displays

pyroclastic flows A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of b ...

of rock fragments deposited as the volcanic ash was forming. Layers of Brisbane tuff can be over thick. It is a form of welded ignimbrite. Brisbane tuff comes in a variety of colours: pink, green, blue (grey) and purple. The different colours are due to the extent of oxidation of iron and

Construction

Brisbane tuff has been used in the construction of the following Brisbane buildings, many of them now heritage-listed: * Commissariat Store, William Street * Cathedral of St Stephen, Elizabeth Street * Old Bishopsbourne Chapel (also known as Chapel of the Holy Spirit), Milton Road * St Martin's House, Ann Street * St Mary's Anglican Church, Kangaroo Point *

Manor Apartment Hotel Manor Apartment Hotel is a heritage-listed former office building and now apartment hotel at 289 Queen Street, Brisbane City, City of Brisbane, Queensland, Australia. It was designed by Hennessey, Hennessey & Co and built from 1930 to 193 ...

, Queen Street (former Colonial Mutual Life building) using Benedict stone * Shell House, Ann Street File:Commissariat Store, Brisbane 10.jpg, Commissariat Store File:St Stephen's cathedral, Brisbane.jpg, St Stephen's Cathedral File:Old Bishopsbourne Chapel.jpg, Old Bishopsbourne Chapel File:St Martin's House, Brisbane, Australia 02.jpg, St Martin's House File:St Mary's Anglican Church, Kangaroo Point, Brisbane, West Front (2009-01-29).JPG, St Mary's Anglican Church, Kangaroo Point File:The Manor Apartment Hotel, Brisbane, Queensland, 2020.jpg, Manor Apartment Hotel File:Shell House, Brisbane, Queensland 02.jpg, Shell House

Benedict stone

Benedict stone is a mixture of cement and crushed Brisbane tuff used on building facades as an alternative to full stone construction. It was manufactured by Benedict Stone (Qld) Pty Ltd which was established by

Roman Catholic Archbishop of Brisbane Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *''Epistle to the Romans'', shortened to ''Romans'', a letter ...

James Duhig Sir James Duhig KCMG (2 September 187110 April 1965) was an Irish-born Australian Roman Catholic religious leader. He was the Archbishop of Brisbane for 48 years from 1917 until his death in 1965. At the time of his death he was the longest-s ...

, to manufacture the stone required for the Holy Name Cathedral,

Fortitude Valley Fortitude Valley (often called "The Valley" by local residents) is an inner suburb of the City of Brisbane, the state capital of Queensland, Australia. In the , Fortitude Valley had a population of 9,708 people. The suburb features two pedestr ...

. The product was developed at the turn of the twentieth century by American manufacturer, Benedict. Duhig obtained a licence from America and opened the Benedict Stone works at

Bowen Hills Bowen Hills is an inner north-eastern suburb in the City of Brisbane, Queensland, Australia. In the Bowen Hills had a population of 3,226 people. Geography Bowen Hills is by road from the Brisbane CBD. Mayne is a neighbourhood within the s ...

on 9 August 1929. In February 1930

Colonial Mutual Life The Colonial Mutual Life Assurance Society Limited, later Colonial Limited, and commonly known as Colonial Mutual, Colonial Mutual Life, and/or CML, was a diverse international financial services company headquartered in Melbourne, Australia. Co ...

(CML) advanced Duhig a mortgage on his properties which included the stone works. A mutually-dependent relationship developed between CML, Duhig and Jack Hennessey, architect. CML used Benedict stone to build a number of their Australian offices, ensuring some of their mortgage was repaid and employed Hennessey and Concrete Constructions (Qld) Ltd, Brisbane (Duhig's architect and contractor for the Holy Name Cathedral).

Tunnelling

The extent and hardness of Brisbane tuff deposits has often been a barrier to building tunnels in Brisbane due to its 100–150

megapascal The pascal (symbol: Pa) is the unit of pressure in the International System of Units (SI), and is also used to quantify internal pressure, stress, Young's modulus, and ultimate tensile strength. The unit, named after Blaise Pascal, is define ...

strength. However, since 2007, advances in tunnel-boring equipment with tungsten carbide cutting heads has enabled a number of major tunnels to be constructed in Brisbane, e.g. the

Clem Jones Tunnel The M7 Clem Jones Tunnel (CLEM7), known during its development as the North-South Bypass Tunnel (NSBT), is a A$3.2 billion motorway grade toll road under the Brisbane River, between Woolloongabba and Bowen Hills in Brisbane, Queensland. ...

which passes through the Kangaroo Point area.

References

External links

*{{Commons category-inline, Brisbane tuff Volcanic rocks Brisbane Geology of Queensland Volcanism of Australia