Northern Australia
Encyclopedia
The term northern Australia is generally known to include two State and Territories
, being Queensland
and the Northern Territory
(NT). The part of Western Australia
(WA) north of latitude
26° south
—a definition widely used in law and State government
policy
—is also usually included. The 26th Parallel also defines the southern border of the NT, whereas much of the southern border of Queensland is defined by 29° south
.
Although it comprises about half of the total area of Australia
, northern Australia includes only about one quarter of the Australian population and only one city of more than one million people (Brisbane
). However, it includes several sources of Australian exports, being coal
from the Great Dividing Range
in Queensland/New South Wales
and the natural gas
and iron ore of the Pilbara region in WA. It also includes major natural tourist
attractions, such as Uluru
(Ayers Rock), the Great Barrier Reef
and the Kakadu National Park
.
that has not experienced geological upheaval since the end of the Precambrian
. the only exception to this generalisation is the Wet Tropics
of northern Queensland, where active volcano
es have been present as recently as the Pleistocene
.
The vast craton in the north and west contains a number of quite rugged mountain ranges, of which the highest are the MacDonnell
and Musgrave Ranges
on the southern border of the Northern Territory. These rise to over 1500 metres (4,921.3 ft), but the most spectacular features are the deep gorges of rivers such as the Finke
. Most of the craton, however, is distinctly flat and generally low-lying with an average elevation of around 400 metres (1,312.3 ft), whilst in the Lake Eyre Basin
most of the land is not far above sea level.
The climate of the north of Australia ranges from arid
(Köppen
BWh) in the south to monsoon
al (Köppen Aw) in the Top End and Kimberley. On the eastern coast, however, the climate is much more humid and ranges from humid sub-tropical (Köppen Cfa around Brisbane and Cwa further north) to humid tropical (Köppen Am and Af) in the Wet Tropics. Except in the western part of the Pilbara and Gascoyne where the heaviest rain often occurs from May to July under northwest cloudbands, rainfall is heavily concentrated in the "summer" months from November to March. For instance, in Burketown
, the months May to September are rainless in over fifty percent of years, with over eighty percent of Augusts having no rain.
Temperatures in summer are generally unpleasantly hot apart from the eastern coastal belt. Maximum temperatures elsewhere between October and April range from 30 °C (86 °F) in the south in April to around 40 °C (104 °F) in the inland Pilbara and Kimberley before the wet season breaks. Further north, maxima are consistently around 32 °C (89.6 °F) but extreme humidity makes conditions very unpleasant. On the coast, maxima in January range from 29 °C (84.2 °F) in the south to 32 °C (89.6 °F), with minima generally around 21 °C (69.8 °F).
In July, temperatures show a wider range, from 31 °C (87.8 °F) in the north to around 19 °C (66.2 °F) in the south, where minima can be as low as 5 °C (41 °F) in Alice Springs in June and July.
, the rainfall over the wet season can vary from less than 100 millimetres (3.9 in) in 1901/1902 to over 2000 millimetres (78.7 in) in 1973/1974. The chief cause of this very high variability is erratic tropical cyclones, which occur from December to April and in many places can deliver as much as 350 millimetres (13.8 in) of rain over a day or two, causing extremely large floods in the region's rivers. For example, in April 1898, a tropical cyclone gave 740 millimetres (29.1 in) in one day at Whim Creek in the Pilbara, but for the whole of 1924 that same station recorded only 4 millimetre (0.15748031496063 in) for the whole year. Tropical cyclones may cross the coast anywhere in Northern Australia but are most frequent between Derby
and Onslow
on the west side and between Cooktown
and Rockhampton
on the east. Inland, variability of rainfall is related to the penetration of the summer monsoon, with high rainfall in seasons like 1973/1974, 1975/1976 and from 1998 to 2001 when the monsoon is most powerful.
Climate change
has seen increases of up to fifty percent in annual rainfall since 1967 over the western half of Australia's tropics, but has not seen any increase over the east. The increase over the west is sometimes attributed to aerosol
pollution
over industrialising areas of China
and India
, but may be related to global warming
.
Frost
s are common in the southern inland during the winter, but in some years, such as 1998, they are much less frequent due to warm pools in the Indian Ocean
.
and adjacent areas to the east, the soils of Northern Australia are quite remarkable in global terms for their low fertility and difficulty of working. Most of them consist chiefly of hard laterite
developed during period of climate much more humid than even that of Darwin
today. Since there has been no mountain building in the region since the Precambrian and no glaciation since the Carboniferous
, the region's soils have generally been under continuous weathering without renewal for over 250 million years, as against less than ten thousand for most soils in Europe
, Asia
, North America
and New Zealand
which have been formed from recent mountain building or glacial scouring of the land.
This immensely long weathering time means that nutrient levels in northern Australian soils are exceptionally low because practically all soluble minerals have long been weathered out. The major constituents of most soils in northern Australia are iron
and aluminium oxide
s, both of which are not only very insoluble but also serve to reduce the soil pH
and remove phosphorus
from the soil as insoluble iron and aluminium phosphate
s. The insolubility of these metal oxides also serves, under the extremely harsh conditions during the dry season in the north and generally in the south, to create massive sheets which are impossible to plough.
In the Lake Eyre Basin, deposition from volcanic regions to the east has produce cracking clay soils
of quite high fertility which are still often fairly low in phophorus but have very good levels of potassium
, calcium
and sulfur
. These soils provide the best grassland for grazing in the region. The youthful, volcanic Wet Tropics has a number of areas of fertile alluvial soils that support intensive horticulture.
to the better power in the dry grasslands since they cannot digest the extreme poor fodder from the northern monsoonal regions. However, the frequency of fires during the desiccating dry season from May to September means that forests cannot establish themselves except in sheltered places. This has created a unique type of tropical savanna environment in which fires play a crucial role in elevating the extremely low nutrient levels and aiding growth during the wet season.
The many large rivers of the region such as the Mitchell, Gilbert-Einasleigh, South and East Alligator, Daly, Ord and Fitzroy support populations of the saltwater
and freshwater crocodile
s, which are by far the best-known animals of the region. There are also a number of species of python. Further south, where rivers are not adequate to support crocodiles, there exist a number of quite unique lizard
species.
The Wet Tropics, like all tropical rainforests, is very rich in unique species, and importantly contains some of the most primitive flowering plants in the world.
growing is a major industry, and the Lake Eyre Basin and surrounding areas where the dominant activity is rearing of sheep and beef cattle
on extremely large properties. Despite the relatively fertile soils, land values owing to the extremely variable climate are very low. Beef cattle are raised elsewhere in the Northern Territory and Kimberley, but the quality of meat is very low because animals are slaughtered at quite an old age compared to cattle elsewhere in the world.
The geological factors that make Northern Australia's soils so unsuited to traditional agriculture, however, make it extremely rich in ores of abundant, insoluble lithophile metals such as aluminium
, iron
and uranium
. It has the world's largest deposits of all these metals, and as less reactive chalcophile metals have been depleted Northern Australia has become very important to the economies of mineral-poor Asian nations. It was Northern Australian iron ore that fed the Japanese post-war economic miracle
and the Four Tigers of South Korea
, Taiwan
, Hong Kong
and Singapore
.
During the 1950s and 1960s, the government of Robert Menzies
attempted to develop farming in Northern Australia, but pests made this impossible even when varieties of rice
suited to the soils were developed. Today, however, sugar cane growing has expanded into the Ord River basin without surpassing cattle and tourism as the main industries of the region.
States and territories of Australia
The Commonwealth of Australia is a union of six states and various territories. The Australian mainland is made up of five states and three territories, with the sixth state of Tasmania being made up of islands. In addition there are six island territories, known as external territories, and a...
, being Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
and the Northern Territory
Northern Territory
The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...
(NT). The part of Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
(WA) north of latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
26° south
26th parallel south
The 26th parallel south is a circle of latitude that is 26 degrees south of the Earth's equatorial plane. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Australasia, the Pacific Ocean and South America....
—a definition widely used in law and State government
Government
Government refers to the legislators, administrators, and arbitrators in the administrative bureaucracy who control a state at a given time, and to the system of government by which they are organized...
policy
Policy
A policy is typically described as a principle or rule to guide decisions and achieve rational outcome. The term is not normally used to denote what is actually done, this is normally referred to as either procedure or protocol...
—is also usually included. The 26th Parallel also defines the southern border of the NT, whereas much of the southern border of Queensland is defined by 29° south
29th parallel south
The 29th parallel south is a circle of latitude that is 29 degrees south of the Earth's equatorial plane. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Australasia, the Pacific Ocean and South America....
.
Although it comprises about half of the total area of Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, northern Australia includes only about one quarter of the Australian population and only one city of more than one million people (Brisbane
Brisbane
Brisbane is the capital and most populous city in the Australian state of Queensland and the third most populous city in Australia. Brisbane's metropolitan area has a population of over 2 million, and the South East Queensland urban conurbation, centred around Brisbane, encompasses a population of...
). However, it includes several sources of Australian exports, being coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
from the Great Dividing Range
Great Dividing Range
The Great Dividing Range, or the Eastern Highlands, is Australia's most substantial mountain range and the third longest in the world. The range stretches more than 3,500 km from Dauan Island off the northeastern tip of Queensland, running the entire length of the eastern coastline through...
in Queensland/New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
and the natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
and iron ore of the Pilbara region in WA. It also includes major natural tourist
Tourism
Tourism is travel for recreational, leisure or business purposes. The World Tourism Organization defines tourists as people "traveling to and staying in places outside their usual environment for not more than one consecutive year for leisure, business and other purposes".Tourism has become a...
attractions, such as Uluru
Uluru
Uluru , also known as Ayers Rock, is a large sandstone rock formation in the southern part of the Northern Territory, central Australia. It lies south west of the nearest large town, Alice Springs; by road. Kata Tjuta and Uluru are the two major features of the Uluṟu-Kata Tjuṯa National Park....
(Ayers Rock), the Great Barrier Reef
Great Barrier Reef
The Great Barrier Reef is the world'slargest reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,600 kilometres over an area of approximately...
and the Kakadu National Park
Kakadu National Park
Kakadu National Park is in the Northern Territory of Australia, 171 km southeast of Darwin.Kakadu National Park is located within the Alligator Rivers Region of the Northern Territory of Australia. It covers an area of , extending nearly 200 kilometres from north to south and over 100 kilometres...
.
Geography and climate
Almost all of northern Australia is a huge ancient cratonCraton
A craton is an old and stable part of the continental lithosphere. Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates. They are characteristically composed of ancient crystalline basement rock, which may be covered by...
that has not experienced geological upheaval since the end of the Precambrian
Precambrian
The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...
. the only exception to this generalisation is the Wet Tropics
Wet Tropics of Queensland
The Wet Tropics of Queensland World Heritage Site consists of approximately 8,940 km² of Australian wet tropical forests growing along the north-east Queensland portion of the Great Dividing Range, stretching from Townsville to Cooktown, running in close parallel to the Great Barrier Reef...
of northern Queensland, where active volcano
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
es have been present as recently as the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
.
The vast craton in the north and west contains a number of quite rugged mountain ranges, of which the highest are the MacDonnell
MacDonnell Ranges
The MacDonnell Ranges of the Northern Territory, are a long series of mountain ranges located in the centre of Australia , and consist of parallel ridges running to the east and west of Alice Springs...
and Musgrave Ranges
Musgrave Ranges
Musgrave Ranges is a mountain range in Central Australia, straddling the boundary of South Australia and the Northern Territory , extending into Western Australia. It is between the Great Victoria Desert to the south and the Gibson Desert to the north...
on the southern border of the Northern Territory. These rise to over 1500 metres (4,921.3 ft), but the most spectacular features are the deep gorges of rivers such as the Finke
Finke River
The Finke River is one of the largest rivers in central Australia. Its source is in the Northern Territory's MacDonnell Ranges, and the name Finke River is first applied at the confluence of the Davenport and Ormiston Creeks, just north of Glen Helen. From here the river meanders for approximately...
. Most of the craton, however, is distinctly flat and generally low-lying with an average elevation of around 400 metres (1,312.3 ft), whilst in the Lake Eyre Basin
Lake Eyre Basin
The Lake Eyre basin is a drainage basin that covers just under one-sixth of all Australia. The Lake Eyre Basin is the largest endorheic basin in Australia and amongst the largest in the world, covering about 1,200,000 square kilometres, including much of inland Queensland, large portions of South...
most of the land is not far above sea level.
The climate of the north of Australia ranges from arid
Arid
A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...
(Köppen
Köppen climate classification
The Köppen climate classification is one of the most widely used climate classification systems. It was first published by Crimea German climatologist Wladimir Köppen in 1884, with several later modifications by Köppen himself, notably in 1918 and 1936...
BWh) in the south to monsoon
Monsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...
al (Köppen Aw) in the Top End and Kimberley. On the eastern coast, however, the climate is much more humid and ranges from humid sub-tropical (Köppen Cfa around Brisbane and Cwa further north) to humid tropical (Köppen Am and Af) in the Wet Tropics. Except in the western part of the Pilbara and Gascoyne where the heaviest rain often occurs from May to July under northwest cloudbands, rainfall is heavily concentrated in the "summer" months from November to March. For instance, in Burketown
Burketown, Queensland
- Morning glory cloud :From the months of August to November, a rare meteorological phenomenon known as "Morning Glory" - long, tubular clouds, some up to 1000 km in length - is often observed in the skies above Burketown.....
, the months May to September are rainless in over fifty percent of years, with over eighty percent of Augusts having no rain.
Temperatures in summer are generally unpleasantly hot apart from the eastern coastal belt. Maximum temperatures elsewhere between October and April range from 30 °C (86 °F) in the south in April to around 40 °C (104 °F) in the inland Pilbara and Kimberley before the wet season breaks. Further north, maxima are consistently around 32 °C (89.6 °F) but extreme humidity makes conditions very unpleasant. On the coast, maxima in January range from 29 °C (84.2 °F) in the south to 32 °C (89.6 °F), with minima generally around 21 °C (69.8 °F).
In July, temperatures show a wider range, from 31 °C (87.8 °F) in the north to around 19 °C (66.2 °F) in the south, where minima can be as low as 5 °C (41 °F) in Alice Springs in June and July.
Climate variability
The above generalisations, however, mask the immense variability of the climate throughout the whole region. With the exception of the extreme north of the Northern Territory, rainfall variability throughout Northern Australia is quite markedly higher than most comparable climates in other continents. For example, at Charters TowersCharters Towers, Queensland
Charters Towers is a city in northern Queensland, Australia. It is located 137 kilometres inland from Townsville on the Flinders Highway. In 2006 the population was 7,979 people, some 450 fewer than in the 2001 census. During the last quarter of the 19th century the town boomed as the rich gold...
, the rainfall over the wet season can vary from less than 100 millimetres (3.9 in) in 1901/1902 to over 2000 millimetres (78.7 in) in 1973/1974. The chief cause of this very high variability is erratic tropical cyclones, which occur from December to April and in many places can deliver as much as 350 millimetres (13.8 in) of rain over a day or two, causing extremely large floods in the region's rivers. For example, in April 1898, a tropical cyclone gave 740 millimetres (29.1 in) in one day at Whim Creek in the Pilbara, but for the whole of 1924 that same station recorded only 4 millimetre (0.15748031496063 in) for the whole year. Tropical cyclones may cross the coast anywhere in Northern Australia but are most frequent between Derby
Derby, Western Australia
Derby is a town in the Kimberley region of Western Australia. At the 2006 census, Derby had a population of 3,093. Along with Broome and Kununurra, it is one of only three towns in the Kimberley to have a population over 2,000...
and Onslow
Onslow, Western Australia
Onslow is a coastal town in the Pilbara region of Western Australia, north of Perth. It currently has a population of around 573 people and is in the Shire of Ashburton Local Government Area....
on the west side and between Cooktown
Cooktown, Queensland
Cooktown is a small town located at the mouth of the Endeavour River, on Cape York Peninsula in Far North Queensland where James Cook beached his ship, the Endeavour, for repairs in 1770. At the 2006 census, Cooktown had a population of 1,336...
and Rockhampton
Rockhampton, Queensland
Rockhampton is a city and local government area in Queensland, Australia. The city lies on the Fitzroy River, approximately from the river mouth, and some north of the state capital, Brisbane....
on the east. Inland, variability of rainfall is related to the penetration of the summer monsoon, with high rainfall in seasons like 1973/1974, 1975/1976 and from 1998 to 2001 when the monsoon is most powerful.
Climate change
Climate change in Australia
Climate change has become a major issue in Australia due to drastic climate events since the turn of the 21st century that have focused government and public attention. Rainfall in Australia has increased slightly over the past century, although there is little or no trend in rainfall in northeast...
has seen increases of up to fifty percent in annual rainfall since 1967 over the western half of Australia's tropics, but has not seen any increase over the east. The increase over the west is sometimes attributed to aerosol
Aerosol
Technically, an aerosol is a suspension of fine solid particles or liquid droplets in a gas. Examples are clouds, and air pollution such as smog and smoke. In general conversation, aerosol usually refers to an aerosol spray can or the output of such a can...
pollution
Air pollution
Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere....
over industrialising areas of China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
and India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, but may be related to global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
.
Frost
Frost
Frost is the solid deposition of water vapor from saturated air. It is formed when solid surfaces are cooled to below the dew point of the adjacent air as well as below the freezing point of water. Frost crystals' size differ depending on time and water vapour available. Frost is also usually...
s are common in the southern inland during the winter, but in some years, such as 1998, they are much less frequent due to warm pools in the Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
.
Soils
Except in the Lake Eyre BasinLake Eyre Basin
The Lake Eyre basin is a drainage basin that covers just under one-sixth of all Australia. The Lake Eyre Basin is the largest endorheic basin in Australia and amongst the largest in the world, covering about 1,200,000 square kilometres, including much of inland Queensland, large portions of South...
and adjacent areas to the east, the soils of Northern Australia are quite remarkable in global terms for their low fertility and difficulty of working. Most of them consist chiefly of hard laterite
Laterite
Laterites are soil types rich in iron and aluminium, formed in hot and wet tropical areas. Nearly all laterites are rusty-red because of iron oxides. They develop by intensive and long-lasting weathering of the underlying parent rock...
developed during period of climate much more humid than even that of Darwin
Darwin, Northern Territory
Darwin is the capital city of the Northern Territory, Australia. Situated on the Timor Sea, Darwin has a population of 127,500, making it by far the largest and most populated city in the sparsely populated Northern Territory, but the least populous of all Australia's capital cities...
today. Since there has been no mountain building in the region since the Precambrian and no glaciation since the Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
, the region's soils have generally been under continuous weathering without renewal for over 250 million years, as against less than ten thousand for most soils in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
which have been formed from recent mountain building or glacial scouring of the land.
This immensely long weathering time means that nutrient levels in northern Australian soils are exceptionally low because practically all soluble minerals have long been weathered out. The major constituents of most soils in northern Australia are iron
Iron oxide
Iron oxides are chemical compounds composed of iron and oxygen. All together, there are sixteen known iron oxides and oxyhydroxides.Iron oxides and oxide-hydroxides are widespread in nature, play an important role in many geological and biological processes, and are widely utilized by humans, e.g.,...
and aluminium oxide
Aluminium oxide
Aluminium oxide is an amphoteric oxide with the chemical formula 23. It is commonly referred to as alumina, or corundum in its crystalline form, as well as many other names, reflecting its widespread occurrence in nature and industry...
s, both of which are not only very insoluble but also serve to reduce the soil pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
and remove phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
from the soil as insoluble iron and aluminium phosphate
Aluminium phosphate
Aluminium phosphate is a chemical compound. It is used in cake mixes and in some baking powders as a leavening agent to help baked goods rise. Medicinally it is used as adsorbent for toxoid.-Uses:...
s. The insolubility of these metal oxides also serves, under the extremely harsh conditions during the dry season in the north and generally in the south, to create massive sheets which are impossible to plough.
In the Lake Eyre Basin, deposition from volcanic regions to the east has produce cracking clay soils
Vertisol
In both the FAO and USA soil taxonomy, a vertisol is a soil in which there is a high content of expansive clay known as montmorillonite that forms deep cracks in drier seasons or years. Alternate shrinking and swelling causes self-mulching, where the soil material consistently mixes itself, causing...
of quite high fertility which are still often fairly low in phophorus but have very good levels of potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
, calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
and sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
. These soils provide the best grassland for grazing in the region. The youthful, volcanic Wet Tropics has a number of areas of fertile alluvial soils that support intensive horticulture.
Flora and fauna
The extreme power poverty of most of Northern Australia has the effect of confining large herbivores such as the kangarooKangaroo
A kangaroo is a marsupial from the family Macropodidae . In common use the term is used to describe the largest species from this family, especially those of the genus Macropus, Red Kangaroo, Antilopine Kangaroo, Eastern Grey Kangaroo and Western Grey Kangaroo. Kangaroos are endemic to the country...
to the better power in the dry grasslands since they cannot digest the extreme poor fodder from the northern monsoonal regions. However, the frequency of fires during the desiccating dry season from May to September means that forests cannot establish themselves except in sheltered places. This has created a unique type of tropical savanna environment in which fires play a crucial role in elevating the extremely low nutrient levels and aiding growth during the wet season.
The many large rivers of the region such as the Mitchell, Gilbert-Einasleigh, South and East Alligator, Daly, Ord and Fitzroy support populations of the saltwater
Saltwater Crocodile
The saltwater crocodile, also known as estuarine or Indo-Pacific crocodile, is the largest of all living reptiles...
and freshwater crocodile
Freshwater Crocodile
The freshwater crocodile , also known as the Australian freshwater crocodile, Johnston's crocodile or colloquially as freshie, is a species of reptile endemic to the northern regions of Australia...
s, which are by far the best-known animals of the region. There are also a number of species of python. Further south, where rivers are not adequate to support crocodiles, there exist a number of quite unique lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
species.
The Wet Tropics, like all tropical rainforests, is very rich in unique species, and importantly contains some of the most primitive flowering plants in the world.
Economy
The erratic climate and extreme soil poverty have defied all attempts to develop large-scale agriculture in any part of Northern Australia apart from the Wet Tropics, where sugar cane and bananaBanana
Banana is the common name for herbaceous plants of the genus Musa and for the fruit they produce. Bananas come in a variety of sizes and colors when ripe, including yellow, purple, and red....
growing is a major industry, and the Lake Eyre Basin and surrounding areas where the dominant activity is rearing of sheep and beef cattle
Beef cattle
Beef cattle are cattle raised for meat production . The meat of cattle is known as beef. When raised in a feedlot cattle are known as feeder cattle. Many such feeder cattle are born in cow-calf operations specifically designed to produce beef calves...
on extremely large properties. Despite the relatively fertile soils, land values owing to the extremely variable climate are very low. Beef cattle are raised elsewhere in the Northern Territory and Kimberley, but the quality of meat is very low because animals are slaughtered at quite an old age compared to cattle elsewhere in the world.
The geological factors that make Northern Australia's soils so unsuited to traditional agriculture, however, make it extremely rich in ores of abundant, insoluble lithophile metals such as aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
, iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
and uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
. It has the world's largest deposits of all these metals, and as less reactive chalcophile metals have been depleted Northern Australia has become very important to the economies of mineral-poor Asian nations. It was Northern Australian iron ore that fed the Japanese post-war economic miracle
Japanese post-war economic miracle
The Japanese post-war economic miracle is the name given to the historical phenomenon of Japan's record period of economic growth following World War II, spurred mainly by Japanese economic policy, in particular through the Ministry of International Trade and Industry...
and the Four Tigers of South Korea
South Korea
The Republic of Korea , , is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China to the south...
, Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
, Hong Kong
Hong Kong
Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...
and Singapore
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
.
During the 1950s and 1960s, the government of Robert Menzies
Robert Menzies
Sir Robert Gordon Menzies, , Australian politician, was the 12th and longest-serving Prime Minister of Australia....
attempted to develop farming in Northern Australia, but pests made this impossible even when varieties of rice
Rice
Rice is the seed of the monocot plants Oryza sativa or Oryza glaberrima . As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in East Asia, Southeast Asia, South Asia, the Middle East, and the West Indies...
suited to the soils were developed. Today, however, sugar cane growing has expanded into the Ord River basin without surpassing cattle and tourism as the main industries of the region.
Further reading
- Richards, Leslie P.(2007) A guide to cruising Northern Australia : anchorages Darwin to Carnarvon Malak, N.T. : Adventure Yarns. ISBN 9780975185742