20°S 145°E Great Basalt Wall – Queensland by Degrees

THE POINT

Degree confluence 20°S 145°E, Google Earth

site

n

Looking north

e

Looking east

s

Looking south

w

Looking west

 

Location: This confluence point is on the property called Glencoe Station. Getting to the site was from Nulla Nulla Road, then 1km on quad bikes across tracks and bushland, and our intrepid GPS trackers got as far as 6.5km to the point where the quad bikes broke down. This point is located in the Charter Towers Regional Council with Pentland 72km to the south-east the closest populated area.

The Landscape: The Basalt River is the main drainage catchment for the point. The landscape is a flat plain. The elevation is 700m above sea level. Black cracking clay and Cainozoic age (less than 66 million years) basalt parent material dot the landscape. Only some scattered Eucalypts, Gum Topped box and Ironbark can be found in this area. Fauna in the form of macropods and feral pigs can be found in this region. The land use is mainly cattle grazing. (Data and photos for 19°56' 494" 145°00'192")

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GPS

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Some points are just not meant to be reached! (Mary Nowill, 2010)

 

Point information and photos: T Hiller, N O' Connor and J & M Nowill  23/5/2010

WITHIN THE DEGREE SQUARE

The Country: This square sits astride the Great Dividing Range with streams such as the Flinders River flowing west to the Gulf of Carpentaria; and the Clark, Basalt and Cape Rivers flowing east to join the Burdekin River which flows to the Coral Sea. The highest point in the square is 981m ASL on the crest of the Range. The lowest elevation is around 350m ASL along the eastern side and south-eastern corner.

The geology of the square is dominated by igneous types including basalt, granite and granodiorite ranging in age from Silurian (444 to 416 million years) along the crest of the Great Dividing Range, to the Cainozoic age (less than 66 million years) Nulla Basalt that makes up most of the north-east quadrant of the square. The youngest basalt however is the Toomba Basalt Flow of the Great Basalt Wall National Park which has been dated at 13,000 years old. It is the youngest basalt flow in Queensland. By contrast the oldest rocks in the square are sandstone, schist and gneiss of Neoproterozoic age (1600 to 1000 million years). These basement rocks are found within the Great Dividing Range with the largest area to the south and west of the Lolworth Range (along the Cape River). The rocks in the White Mountain National Park along the southern side of the square are Triassic age (251 to 200 million years) sandstone.

Vegetation across the square is mainly grassland or open savannah woodland except in the Great Basalt Wall National park which carries a dense mid height forest. A wide range of birds, mammals and reptiles are found across the area. Land use is predominantly cattle grazing.

 

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Typical woodland (Mary Nowill, 2010)

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Curious cattle (Mary Nowill, 2010)

 

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Great Basalt Wall National Park contrasts with the surrounding country (Google Earth image)

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The Climate: The climate of the area is classified as being grassland with a winter drought. The closest representative Bureau of Meteorology climate is the Hughenden Post Office, which is approximately 125 km to the south-west of the degree confluence, and has an elevation of 324 m. The station has been recording data since 1884.

 

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Year

Mean max
(ºC)

35.8

34.7

33.7

31.4

27.9

25.0

25.0

27.5

31.1

34.5

36.1

36.9

31.6

Mean min
(ºC)

22.5

22.1

20.5

17.0

13.2

9.8

8.8

10.4

14.0

18.0

20.5

22.0

16.6

Mean rain
(mm)

114.5

98.0

58.2

26.0

17.8

18.6

11.6

7.9

9.0

22.3

36.0

71.1

492.4

The highest temperature to be recorded was 44.0°C in December 1996, and the lowest was -2.0°C in July 1984. The greatest rainfall recorded in any year was 1 085.1 mm in 1891, and the least was 150 mm in 1926.

Extremes of Nature: The area is subject to the impact of tropical cyclones. The database maintained by the Bureau of Meteorology shows that 27 cyclones have passed within 200 km of the confluence, although only two have passed within 50 km (TC Althea in 1971, and TC Aivu in 1989). These and more distant cyclones bring with them potentially destructive winds that can cause widespread damage and intense rainfall that can produce severe flooding.

 

Cyclone tracks within 200 km of point 1906 to 2006 (Bureau of Meteorology web site)

On average the area experiences around 20 to 30 thunder days each year. Severe thunderstorms bring with them potentially destructive winds, intense rainfall and lightning strike. The intense rainfall can lead to flash flooding and the lightning can spark bushfires if there is sufficient fuel to sustain spread.

Bushfires can cover very large areas in this region in the dry winter and autumn months. Such fires may be deliberately lit to manage vegetation and to promote pasture growth or they may be wildfires.

Extreme heat is also a serious issue. The climate records for Hughenden show that on average the area experiences 101 days a year with temperatures over 35oC and nine days with temperatures of 40oC or more. Such extreme temperatures can cause heat stroke and death if appropriate measures are not taken such as avoiding strenuous physical effort, keeping as cool as possible and drinking lots of water. Heat waves kill more people in Australia than all other natural hazards combined. 

There are no earthquake epicentres within the degree square recorded in the National Earthquake Database maintained by Geoscience Australia.

The Indigenous Story: Most of the land within the square is the traditional country of the Gugu-Badhun people.

MORE INFORMATION WELCOME

European Exploration and Settlement: The first European explorer to pass through this area was Ludwig Leichhardt on his epic expedition from the Darling Downs to Port Essington in 1844. Augustus Gregory also followed through the area in 1855 and the Jardine brothers Frank and Alexander drove their heard of cattle through the area on their way to Somerset at the tip of Cape York in 1864. The area was also crossed by two expeditions searching for Burke and Wills in 1861, they were led by John McKinlay and Frederick Walker.

Pastoralists followed these expeditions with cattle and sheep.

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Today:

The total population of the degree square at the 2011 national Census was 525, though a proportion of this population were very likely located in neighbouring degree squares. This is because of changes to census boundaries.

MEASURE

1996

2001

2006

2011

Total population

302

219

181

525

Total males

185

123

92

287

Total females

117

96

89

238

Under 5 years

24

18

11

37

65 years and over

42

17

14

95

Indigenous

6

10

7

18

The steady decline in the size of the population over the past three censuses can probably be related to the impact of drought on the pastoral industry.

The major land use across the area is cattle grazing. This industry is supported by a network of 960km of public roads and a comparable network of private roads and tracks on the station properties. Most stations also have their own small airstrip.

The area falls mostly within the Charters Towers Regional Council; there is a section of Flinders Shire in the south-west corner of the square. There are two national parks within the square - Great Basalt Wall NP and the northern section of White Mountain NP.

MORE INFORMATION WELCOME

Site Summary:

Location

On Glencoe Station 10km west of the Great Basalt Wall NP

Access

By quad bike on station tracks and cross country (point not reached)

Nearest settlement

Pentland is 72 km south-east

Terrain

Low undulating country

Catchment

Basalt River which is a tributary of the Burdekin River

Geology & soils

Basalt of Cainozoic age

Vegetation

Grassland and open savannah

Land use

Cattle grazing

Climate

Grassland with a winter drought

Population in degree square

181 at the 2006 census

Infrastructure

960km of public roads, private station roads and tracks, station airstrips

National Parks

Great Basalt Wall NP and Mt White NP

Compilers: Jo Grant and ken Granger, 2010

Edited by: Hayley Freemantle

References: various web sites including local governments and Bureau of Meteorology.

EPA 2001: Heritage trails of the Queensland outback, Queensland Environmental Protection Agency, Brisbane.

Google Earth