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Tower Hill
*(Koroitj)*
Tower Hill; (Koroitj)
	Tower Hill; (Koroitj) Victoria, Australia
Highest point
Elevation	103 m (338 ft)
Coordinates	38°19′17″S 142°21′35″E / 38.3213°S 142.3597°E
Geography
Location	Victoria, Australia
Geology
Last eruption	34,000 BP

Tower Hill is an inactive volcano on the south-west coast of Victoria, Australia, approximately 275 kilometres (171 mi) west of Melbourne, and 15 kilometres (9 mi) north-west of Warrnambool. The Tower Hill crater is roughly 3 kilometres (2 mi) wide and 80 metres (260 ft) high, with a gradient of between 10% and 80% at the higher points. Within the crater, a series of later volcanic explosions formed a number of scoria cones and spheres, surrounded by a crater lake. Being a giant nested maar, Tower Hill is of international geological significance. The Dhauwurdwurrung name for the volcano is Koroitj.^[1]

History

Aboriginal Australian kitchen middens at Tower Hill contain 5000-year-old Tasmanian devil bones.^[2] Greenstone axe heads and other artefacts excavated from the tuff indicate that Aboriginal people were resident in the area when the volcano erupted. A basalt tool dubbed the "Bushfield Axe", found buried under volcanic ash near Tower Hill in 1947, was particularly significant. The archaeological evidence aligns with local people's oral histories of volcanic eruptions, indicating the longevity and truth of those histories.^[3] The Koroitgundidj people long inhabited this region of Australia, and their descendants retain special links with the area.^[4]

In 1990, the most recent eruption was dated to c.25,000 BP.^[5] However, in February 2020, a study was carried out by the University of Melbourne's School of Earth Sciences' David Phillips and three other researchers, using a more sophisticated form of radiometric dating known as argon-argon dating, showed that both the Budj Bim and Tower Hill volcanoes erupted at least 34,000 years ago.^[3] Specifically, the Tower Hill eruption was dated at within 3,800 years either side of 36,800 years BP. Significantly, that is a "minimum age constraint for human presence in Victoria", and also could be interpreted as evidence for the Gunditjmara oral histories which tell of volcanic eruptions being some of the oldest oral traditions in existence.^[6]

The first confirmed sighting of Tower Hill by Europeans was in 1802, by French explorers sailing with Nicolas Baudin on Géographe. Matthew Flinders sailed east along the southern coast of Australia and, on 20 April 1802, referred in the ship's log to "Peaked Hill Position uncertain", which may refer to Tower Hill.^[7]

In 1855, the Hill was painted by the artist Eugene von Guerard, the foremost landscape artist in the colonies at the time. The painting Tower Hill, 1855^[8] is now in the Warrnambool Art Gallery.^[9] The painting was used as a source of information of local native vegetation when an extensive revegetation project was undertaken in the Tower Hill Wildlife Reserve from 1961.^[10]

Naming

The origin of the English name, Tower Hill, is not certain. One source suggests that it arose in the 1840s owing to its resemblance to a castle, while another credits a sailor from Glasgow with "naming the site after Tower Hill in Scotland".^[11]

Location

The town of Koroit is on the north rim of Tower Hill, within easy reach of both Warrnambool and Port Fairy. The volcano is located about 275 kilometres (171 mi) west of Melbourne and 15 kilometres (9.3 mi) north-west of Warrnambool.^[12]

Description

Tower Hill's formation is known as a "nested maar", the largest of its type in Victoria. It was created by molten lava pushing its way up through the Earth's crust, before hitting a layer of water-bearing rock, which led to huge explosions. A shallow crater was left, later becoming a lake after it filled with rainwater. Subsequent to this, later eruptions occurred in the centre of this crater-lake, pushing up islands and cone-shaped hills,^[12] known as scoria cones.^[13]

It is "one of the largest eruption points of the Pleistocene Newer Volcanics Province of Victoria". The main crater is 3.2 kilometres (2.0 mi) by 2.4 kilometres (1.5 mi). Within the steep-walled tuff ring is a crater with a depth of over 90 metres (300 ft). Because of the complex nature of its formation and structure, and as one of the largest maars in the world, it is of great geological significance both nationally and internationally.^[13]^[12]

Tower Hill volcano is roughly 4 kilometres (2.5 mi) wide and 80 metres (260 ft) high, and as a giant maar (volcanic explosion crater), it is of international and national geological significance. It has a gradient of between 10% and 80% at the higher points.^{[citation needed]}

Reserve

Now part of the state park system as the Tower Hill Wildlife Reserve, the area had been used since European settlement for farming and stone quarrying. The area has been reforested with native flora, and repopulated with native fauna since 1961.^[14]^[15]^[10]

Brown's Quarry

Brown's Quarry, on the southern side, was created in about 1951, but since around 1977 has only been used for dumping clean landfill. As of 2021^[update] there is debate about what to do with the site next. The owners of the quarry would like to fill the quarry and restore the vegetation, arguing that this would make the perimeter of the volcano safer and allow a walking track to be built around it (which is part of the Tower Hill master plan), but geologists say that the wall of the quarry is very important for scientific analysis and understanding of the geology of the area and volcanoes in general, which is evolving all the time.^[16]

Gallery

Large panorama of crater, from the south, looking north.
Visible are the scoria cones forming the 'islands' in the middle of the crater, and the lake and far rims of the larger crater.
Note the layering in the far right-hand side of the image.

Notes

^ Ian Clark, 'Reconstruction of Aboriginal microtoponymy in western and central Victoria' in Harold Koch and Luise Hercus (eds), Aboriginal Placenames: Naming and Re-naming the Australian Landscape (ANU E Press and Aboriginal History Incorporated, 2009) <http://press-files.anu.edu.au/downloads/press/p17331/html/ch08.xhtml?referer=xxxxxx&page=17>
^ Owen, David; Pemberton, David (2005). Tasmanian Devil: A unique and threatened animal. Allen & Unwin. ISBN 978-1-74114-368-3. p. 41.
^ ^a ^b Johnson, Sian (26 February 2020). "Study dates Victorian volcano that buried a human-made axe". ABC News. Retrieved 9 March 2020.
^ "Victorian Heritage Database". VHD. Retrieved 9 March 2020.
^ Orth, K.; King, R. (1990). The Geology of Tower Hill. Department of Industry, Victoria. ISBN 0 7241 9733 8. p. 3.
^ Matchan, Erin L.; Phillips, David; Jourdan, Fred; Oostingh, Korien (2020). "Early human occupation of southeastern Australia: New insights from 40Ar/39Ar dating of young volcanoes". Geology. 48 (4): 390–394. doi:10.1130/G47166.1. ISSN 0091-7613. S2CID 214357121.
^ "Site: Tower Hill (Vic)". Matthew Flinders and the Coastal Landforms of Southeastern Australia (website). Archived from the original on 23 July 2008. Retrieved 24 June 2008.
^ Tower Hill
^ "Site: Artist's Footsteps". Department of Education, Training and Youth Affairs (website). Retrieved 11 September 2015.
^ ^a ^b "Tower Hill Reserve: History and Heritage". worngundidj.org.au. Retrieved 9 March 2020.
^ "Tower Hill Reserve – History and Heritage" (PDF). Parks Victoria. Retrieved 9 March 2020.
^ ^a ^b ^c "History & Heritage". Tower Hill (Worn Gundidj Corporation). Retrieved 9 March 2020.
^ ^a ^b "Tower Hill". Victorian Resources Online. Retrieved 9 March 2020. This information has been obtained from the report: Eruption Points of the Newer Volcanic Province of Victoria by Neville Rosengren. This report was published in 1994 and was prepared for the National Trust of Australia (Victoria) and the Geological Society of Australia (Victorian Division). The review of eruption points was based on an earlier unpublished manuscript Catalogue of the post-Miocene volcanoes of Victoria compiled by O P Singleton and E B Joyce (Geology Department, University of Melbourne 1970).
^ "Tower Hill Wildlife Reserve, Attraction, Great Ocean Road, Victoria, Australia". Visit Victoria home. 13 February 2018. Retrieved 8 March 2020.
^ "Tower Hill State Game Reserve". Parks Victoria. Archived from the original on 21 July 2006. Retrieved 8 March 2020.
^ Lee, Jeremy (9 May 2021). "Ancient volcano secrets revealed by old Tower Hill quarry could be reburied". ABC News (Australian Broadcasting Corporation). Retrieved 10 May 2021.