User:Moizbu/East Australia Hot Spot

East Australia Hotspot
The East Australia hotspot is a volcanic province in southeast Australia which includes the Peak Range in central Queensland, the Main Range on the Queensland-New South Wales border, Tweed Volcano in New South Wales, and the Newer Volcanics Province (NVP) in Victoria and South Australia. A number of the volcanoes in the province have erupted since Aboriginal settlement (46,000 BP). The most recent eruptions were about 5,600 years ago, and memories of them survive in Aboriginal folklore. These eruptions formed the volcanoes Mount Schank and Mount Gambier in the NVP. There have been no eruptions on the Australian mainland since European settlement.

Unlike most hotspots, the East Australia hotspot has explosive eruptions similar to the runny lava flows of the Hawaii hotspot, the Iceland hotspot and the Réunion hotspot. The hotspot is thought to be explosive because basaltic magma interacts with groundwater in aquifers below the surface producing violent phreatomagmatic eruptions.

The cause of volcanism in the area is uncertain. Theories typically fall into one of two categories: the mantle plume theory and the plate theory. On the basis of the long duration of volcanic activity, its vast lateral extent, geochemistry of lavas, and seismic data, it has been proposed that the region is underlain by one or more deep mantle plumes which have forced magma up through points of weakness in the Indo-Australian Plate as it has moved northward over the source.

The lack of clear age progression across the province and the orientation of the NVP, which is orthogonal to plate motion, are inconsistent with plume models. Furthermore, seismic anomalies terminate at a depth of around 200 km, making the presence of a mantle plume unlikely.

Various tectonic causes have been proposed. Some studies have argued that volcanic activity results from a combination of edge-driven convection (small-scale, shallow mantle convection caused by a change in lithospheric thickness at the continental margin where thick continental lithosphere meets thinner oceanic lithosphere) and decompression of the crust from normal faulting caused by plate stresses. Another view is that extension from stresses brought about by changes in plate boundary configurations has caused severe lithospheric thinning resulting in decompression melting of the asthenosphere. Both of these models invoke shallow processes closely related to the operation of plate tectonics and so fall under the plate theory. Other models combine both plume and plate-tectonic processes.

Aboriginal Folklore Connections
 History 

Aboriginal Australians migrated to Australia more than 60,000 years ago, and reached south-east Australia by 40,000 BP. The Aboriginals had strong oral traditions that were passed down through generations by story, song, dance, material culture, and art. Specifically, the myths told can act as records of natural events, and they can then be utilized by modern scientists to understand historical geological events.

In the NVP, there were three groups of Aboriginal people. The Kulin nation in central and western Victoria, and the Maar nation on the southwest coast of Victoria and the Bunganditj nation at the South Australian border with Victoria.

Stories told by aboriginals accurately depict the creation of the Eacham, Barrine, and Euramoo crater lakes in Queensland in 10,000 BP. Furthermore, the Gugu Badhun people of North Queensland tell stories that describe the lava flows that occurred around 7,000 years ago, and the toxic ash clouds that spread across a wide area, asphyxiating many.

Aboriginal people who liked in the NVP were the Kulin nation in central and western Victoria, and the Maar nation on the southwest coast of Victoria and the Bunganditj nation at the South Australian border with Victoria.

 Budj Bim 

Budj Bim is dormant volcano in southwestern Victoria, it is a part of the NVP. Budj Bim, also known as the Budj Bim Cultural Landscape, is a Gunditjmara which means "high head" It formed around 37,000 years ago through a series of rapid eruptions. The Gunditjmara people retell the story of their people who witnessed the creation of an important being, he was known as Budj Bim, one of four giant beings who arrived in southeast Australia. While three of them strode out to other parts of the continent, one stayed in place; that was Budj Bim. His body transformed into the volcano later given the same name, and his teeth became the lava that transformed the landscape.

 Theories and Disagreements 

In 1878, Robert B. Smyth, a mining engineer and geologist raised a question on how Aboriginal Australians get fire, he agreed that there were active volcanoes in Victoria, however he claimed that there was a large uncertainty on whether or not people actually inhabited that land. However it was later proven that Smyth had an incomplete idea of Australia's geological past.