Gawler Ranges

From Wikipedia, the free encyclopedia
For other uses, see Gawler Ranges.
Gawler Ranges
Chaine Gawler Australie.jpg
Columnar jointing in rhyolite at the "Organ Pipes" waterfall in the ranges
Highest point
PeakNukey Bluff
Elevation465 m (1,526 ft)
Geography
CountryAustralia
StateSouth Australia
RegionEyre Peninsula
Range coordinates32°32′S 135°22′E / 32.533°S 135.367°E / -32.533; 135.367Coordinates: 32°32′S 135°22′E / 32.533°S 135.367°E / -32.533; 135.367
Geology
Age of rockMesoproterozoic
Type of rockFelsic Volcanics
Conical Hill Track in the Gawler Range
Acraman Salt Lake with Gawler Range in background
Splendid fairywren in the Gawler Range
Wagon on the Mail road, near Thurlga turnoff, Gawler Ranges

The Gawler Ranges are a range of stoney hills in South Australia to the north of Eyre Peninsula. The Eyre Highway skirts the south of the ranges. The Gawler Ranges National Park is in the ranges north of Kimba and Wudinna. The ranges are covered by the Gawler Ranges Native Title Claim.

History[]

The ranges were named by Edward John Eyre after the Governor of South Australia, George Gawler in 1839.[1] This was on one of Eyre's earlier expeditions before his famous crossing of the Nullarbor Plain further west. And it was on this expedition that Edward John Eyre made the first recorded sighting of South Australia's floral emblem, the Sturt desert pea, in 1839 during an early exploration of the region.[2]

Stephen Hack explored the range in 1856 and in 1857 the first pastoral lease was taken up in the area and more sheep stations were soon established. Two good seasons followed in 1857 and 1858 with pastoralists reporting permanent freshwater lakes on their runs. Stations were required to stock 50 sheep per square mile (19 per square kilometre) but soon properties such as Nonning were shearing flocks of 90,000. The first mail service from Port Augusta to Yardea commenced in 1876, with the telegraph service to Western Australia that passes through the range commencing in 1903[3]

Environment[]

Geology[]

The rocks within the ranges were formed by volcanic activity between ~1595-1592 Ma, when the Gawler Range Volcanics were erupted.[4] Approximately 30 000 km³ of dominantly rhyolitic and dacitic lava were rapidly extruded, and their eroded remnants preserve one of the most voluminous felsic magmatic events preserved on earth. Basaltic and basaltic-andesite comprise a remarkably minor component of the magmatism (<1%). The Gawler Ranges Volcanics were also erupted at remarkably high temperatures (~950-1100 °C) for felsic magmas, and this, coupled with their very high halogen (particularly F and Cl) compositions resulted in highly viscous (runny) magmas when compared to typical rhyolites and dacites which are generally several hundred degrees cooler. This high viscosity resulted in emplacement as a series of lobate flows with a stacked pancake-like morphology which cooled rapidly resulting in porphyritic textures and widespread columnar jointing.The ranges are a small part of the Gawler Craton which is a craton rich in mineral resources, although many are only recently discovered and not yet fully exploited.

At approximately 580Ma the Gawler Ranges were impacted by a large meteorite which excavated the Acraman impact crater, in which the modern Lake Acraman now sits. The original crater was possibly as large as 90 km in diameter and flung fist sized debris several hundred kilometres to the east where it has been preserved in sediments which now comprise the Flinders Ranges.

Geomorphology[]

The highest point is Nukey Bluff at 465 metres (1,526 ft) above sea level. Bornhardts dominate the landscape.[5] Soils are invariably dominated by the weathering products of the volcanics, and are typically red in colour due to abundant oxidised iron weathering in the arid environment. No major rivers drain the ranges, however several internal catchments feed the modern playa lakes Gairdner, Acraman, Everard, McFarlane, Harry and Island Lagoon.

Birds[]

There are some 140 species of birds in the Gawler Ranges, including the emu, wedge-tailed eagle, Major Mitchell's cockatoo and singing honeyeater.[2]

Mammals[]

The Gawler Ranges are home to several larger mammals, like the southern hairy-nosed wombat[6] and the endangered yellow-footed rock wallaby.[7]

See also[]

Notes[]

  1. ^ "Gawler Ranges National Park" (PDF). Department for Environment and Heritage. Archived from the original (PDF) on 2008-07-31. Retrieved 2009-11-12.
  2. ^ Jump up to: a b South Australia - Gawler Ranges
  3. ^ "History of the Gawler Ranges". Mt Ive Station. Archived from the original on 29 March 2012. Retrieved 15 March 2015.
  4. ^ Pankhurst et al., 2011 A Mesoproterozoic continental flood rhyolite province, the Gawler Ranges, Australia: the end member example of the Large Igneous Province clan
  5. ^ Campbell, E.M.; C.R. Twidale (February 1991). "The evolution of bornhardts in silicic volcanic rocks in the Gawler Ranges". Australian Journal of Earth Sciences. Taylor & Francis. 38 (1): 79–83. Bibcode:1991AuJES..38...79C. doi:10.1080/08120099108727957. ISSN 1440-0952.
  6. ^ Deborah Furbank (2010): Briefing note on the Southern Hairy-nosed Wombat. Yorke Peninsula Natural Resource Management Group PDF Archived 2012-03-25 at the Wayback Machine
  7. ^ Informationsbroschüre des Parkverwaltung, engl., pdf Archived 2011-03-14 at the Wayback Machine

Further reading[]

Retrieved from ""