Tweed Volcano
Coordinates: 28 ° 23 ′ 44.7 ″ S , 153 ° 16 ′ 0.2 ″ E
The Tweed Volcano was a shield volcano from the early Miocene . It is located in northeastern New South Wales in Australia and was formed 23 million years ago. It is one of the largest volcanoes on earth and the largest eroded volcano in the southern hemisphere.
For a period of three million years, the Tweed Volcano was fed by the East Australia Hotspot when it was below the Australian continent. There have been no eruptions or pyroclastic currents for about 20 million years as the hotspot moved outside of the Australian continent due to continental drift.
The Tweed Volcano eruptions formed numerous layers of lava and volcanic ash and spread over an area from Byron Bay in the southeast, Lismore in the southwest in New South Wales and to Mount Tamborine in northern Queensland . Mount Warning , Lamington Plateau and the Border Ranges between New South Wales and Queensland are the most significant visible relics of this volcano, which originally stretched over an area of 100 km in diameter. The volcano used to have a height of about 2000 m, while today's widely visible Mount Warning rises 1156 m above the terrain. Despite its size, the Tweed Volcano was not a super volcano .
In the 20 million years after the eruptions ended, severe erosion took place, exposing the remains of the caldera around the volcanic plug of Mount Warning and creating numerous rivers such as the Rous and Oxley Rivers that flow into the Tweed River . The caldera of the volcano descends over 1000 m and has a diameter of 40 km.
The Tweed Volcano's lava has been stratigraphically determined to be part of the Lamington Volcanics . The volcanic stratigraphy of this volcano is comparable to many other hotspot volcanoes on earth that produced eruptions of tholeiitic and other alkaline basalts .
Individual evidence
- ↑ a b c bigvolcano.com.au : The Caldera of the Tweed Volcano , in English, accessed November 27, 2011.
- ↑ Knesel KM, Cohen BE, Vasconcelos PM, Thiede DS (2008): Rapid change in drift of the Australian plate records collision with Ontong Java Plateau , Nature Vol 454, pp. 754–757 (English)
- ↑ dbforms.ga.gov.au : Geoscience Australia Lamington Volcanics Stratigraphy , in English, accessed November 27, 2011