Features of the relief and mineral resources of Australia. Geology and minerals of Australia

Australia is the most controversial continent on our planet. Due to its remoteness, it was opened later than the others. Even ancient scientists spoke about the continent located in the southern hemisphere. But it was discovered only in 1770 by James Cook. Today we will look at the topography of mainland Australia and the minerals that the continent is rich in.

What do we know about Australia?

Australia was once part of the supercontinent Gondwana. 15 million years ago Gondwana split into 2 parts - western and eastern. The western one is represented by Africa, Saudi Arabia and South America, and the eastern one - by Madagascar, Hindustan, Australia and Antarctica. 90 million years ago, the division of Hindustan and Madagascar occurred, and 50 million years later Australia and Antarctica “diverged.”

However, according to another scientific version, Australia was the first to separate from Gondwana. This explains its unique flora and fauna. Some examples of plants and animals have not undergone significant changes over thousands of years.

The name of the continent comes from australis, which means "southern". After all, Australia is located in the southern hemisphere of the planet. This is the smallest continent. Its area is almost the same size as the United States (if you do not take Alaska into account).

History of the continent from the Aborigines to the British

Despite the fact that Cook is called the discoverer of Australia, before that it was visited several times by the Spaniards and the Dutch. However, the local aborigines greeted them very hostilely, and the sailors hastened to leave the uncharted lands. Today, indigenous people who belong to the Australoid racial type make up only 1% of the continent's population. Most of the inhabitants of Australia are descendants of settlers (including convicts who served sentences in Australia).

The aborigines themselves appeared on the mainland 40-60 thousand years ago. They were engaged in fishing and hunting, but after the discovery of the mainland, the idyll ended. Great Britain laid its hand on the continent. The British conquered more and more land until they drove the Aborigines inland, where they died of starvation and diseases brought by the whites. Even today, Australia's central regions are considered less habitable. Most cities are concentrated along the coast.

Relief of Australia

Australia's topography is dominated by 95% plains. The types of its structure can be divided into several parts.

1. Eastern.

2. Western.

These are the largest landforms in Australia. We'll look at each of them in more detail later.

At the heart of Australia is an ancient platform of the Precambrian period. Therefore, the predominant landform of Australia is flat. It is covered with a thick layer of sedimentary rocks of continental and marine origin. In some areas, the slab comes to the surface, forming shields. The shield is a part of the Precambrian plate that comes to the surface, forming relatively flat areas. After the end of the Cambrian period in Australia, shields, as a form of relief, are not subject to tectonic phenomena.

It is noteworthy that in Australia there are no active volcanoes (unlike the islands of Oceania) and icy mountain peaks. There are no earthquakes here either.

The waters washing the continent (mainly the Indian Ocean) are always warm. Their temperature does not fall below +20 degrees. This is why coral reefs are growing so actively around the mainland. The Great Barrier Reef, which is 347,800 km long. sq., is the largest in the world. However, in 2016 it became known that corals were dying in huge quantities due to the influence on them carbon dioxide. All this is the result of human activity.

Australia is the lowest continent. Therefore, the relief of Australia is represented mainly by plains, elevated at the edges. This is especially noticeable in its eastern region. Let's look at the main landforms of Australia.

Western Australian Tablelands

The western part of the continent is represented by the Western Australian Plateau. It has a height of up to 400-500 m. The edges are elevated. It occupies the entire western region of the continent and is adjacent to the Central Lowland.

Highest points:

• in the north - the Kimberley massif, highest point - 936 m;
• on the east - Musgrave Ridge, 1140 m, and MacDonell - 1510 m;
• in the west - Hamersley Ridge, 1226 m;
• in the southwest - the Dargling ridge, 582 m.

The Western Australian Tablelands lies on an ancient platform. It is represented mainly by semi-desert and desert plains. Ancient gneisses and granites crop out in the southwest.

Central lowland

The Central Lowlands are another landform of Australia. Covered with thick sedimentary rocks. Most of it is depressed (from the Latin depressio - decrease, depression). The highest points do not exceed 100 m in height. Its lowest point is the salt lake Eyre (in honor of the explorer Edward Eyre who discovered it). Its depth reaches 15 m. It is noteworthy that the lake is practically devoid of water. It is covered with a salty crust 4 m thick. Its surroundings are covered with clay and salt. That’s why there are practically no living creatures on the lake. Once a season, the lake comes to life (the result of precipitation and seasonal water flows), but it is completely filled with water only once every 80 years.

The sedimentary rocks covering the central lowland were formed at a time when marine and lacustrine regimes dominated here. Today the central lowland is almost entirely represented by semi-desert. The flora and fauna are sparse. However, in the north you can find a greater variety - kangaroos, ostriches, parrots, lizards and snakes.

The highest point of the Central Lowlands is the Flinders Mount Lofty Range. The height of Mount Lofti is 727 m.

Great Dividing Range

Great Dividing Range - mountain system, the length of which is more than 4,000 km. Maximum width - 1500 km. Scientists suggest that the formation of the ridge began 300-500 million years ago. But it acquired its modern shape only 25 million years ago.

The mountains consist of limestone, gneiss, granite. It is also known about deposits of gas, oil, gold, and copper. Most of them are located in the central region of the mountains - the Sydney-Bowen Trough. Later we will look at the minerals that the continent is rich in in more detail.

Australia's largest river, the Murray, originates on the western slopes of the Great Dividing Range.

Aboriginal tribes lived here for a long time. In the caves you can find mysterious drawings that were made thousands of years ago. The huge mountain system inspired them with special respect. Thus, the Gundungur tribes believed that the mountains were formed as a result of a battle between two opponents, whose appearance was a mixture of fish and reptiles. Also, the culture of tribes is rich in legends about people who knew how to take on an animal form.

In addition, one of the highest parts of the Dividing Range is the Australian Alps in southern region New Wales. They include nature reserves and national parks. There is snow here for six months. The abundance of ski resorts makes the Alps incredibly popular among tourists.

The highest point in all of Australia is Mount Kosciuszko, 2,228 meters above sea level. Climbing this mountain is the most popular route among tourists.

Minerals of Australia

Australia's topography and mineral resources are of great interest to geologists. Ancient rocks (the main component of the continent) with an abundance of minerals make the continent one of the largest raw material powers in the world. So, there are gold deposits throughout the territory. Most of them are concentrated in the west, near the town of Coolgardie.

On the mainland there are reserves of polymetallic and uranium ores, as well as bauxite ( bauxite). The Hamersley Range (western Australia) is rich in iron and iron ore. A large deposit has been discovered in the desert western regions of New Wales, where polymetallic ores, lead, zinc, copper and silver are mined. There are also chromium deposits in the west.

However, this does not mean that the state is experiencing a shortage of non-metallic minerals.

In the east of the continent there are large quantities of coal deposits. Oil and gas deposits have been discovered in the Great Artesian Basin, Lake Victoria and the Amadies Trough. Geologists are confident that there are a lot of natural gas deposits in the bowels of the continent and on the shelf.

In addition, in addition to non-metallic minerals, clay, limestone, sand, asbestos, mica and other building materials are mined in Australia.

Climate of Australia

The continent's climate is mostly arid. However, 6 climate zones make it incredibly diverse - from the heat of the deserts to the snow-capped peaks of the Australian Alps.

The temperature remains above zero almost all year round. But June is considered the coldest month. It even snowed here in June 2016. This is due to the fact that Australia is a southern continent. When it is winter in the Northern Hemisphere, it is summer here. The hottest months are from November to January. Temperatures range from +20 to +42. However, in the evenings it drops sharply to +10. In general, Australia's climate is mild, with hot summers and damp, warm winters. There are no sharp changes in temperature throughout the year.

Conclusion

So, today we described the relief of Australia. This is the most controversial and interesting continent to study. It is incredibly diverse and unusual. This explains the popularity of the mainland among tourists. Unique flora and fauna, modern cities And warm weather- what else is needed for happiness?

The relief of Australia is unique. 95% of the continent has an altitude of no more than 600 meters above sea level. These are mostly plains. Mountains occupy only 5% of the entire continent.

Forms and main indicators of heights

The topography of Australia has remained virtually unchanged since Precambrian times; there have been no serious tectonic movements.

Australia, like Africa, was once part of big continent Gondwana. The separation of Austria from Gondwana occurred in the Mesozoic.

The relief of the continent was greatly influenced by a process such as denduation - this is the process of transfer, demolition (under the influence of natural forces) of the products of crushing rocks into low-lying areas. It was during this process that the peneplain appeared - spacious plains with low island mountains.

Fig 1. Relief map of Australia

The basis for the relatively flat relief was the Precambrian Australian platform, which, in turn, is part of the Indo-Australian lithospheric plate, and the relatively young Epihercynian platform. Some experts note that the basis for the flat relief of the continent is also the Hindustan Platform (it is also part of the Indo-Australian lithosphene plate).

A table can be used to briefly describe all forms of Australian relief, indicating heights.

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Region	Relief	Average altitudes (above sea level)	Maximum/minimum altitudes (above sea level)
Western Australia	Western Australian Tablelands	400 - 500 meters	Mount Woodroffe (Musgrave Range) -1440 meters; Mount Zil (McDonnell Range - 1510 meters
Central Australia	Central Lowlands (Lake Eyre region)	100 meters	12 meters (in the Lake Eyre area)
Eastern Australia	Plains (deserts and semi-deserts of Victoria, Great Sandy and Great Artesian Basin), foothills and mountains (Australian Alps and Great Dividing Range)	300 -600 meters	Mount Kosciuszko (Australian Alps) - 2230 meters. This is the highest point of the entire continent.

Fig 2. Mount Kosciuszko in Australia

Australia has no active volcanoes or manifestations of modern glaciation. In some places, cones of ancient extinct volcanoes have been preserved, but no tectonic activity has been observed, although, most likely, in the past this continent was one of the centers of tectonic activity on the planet.

Landforms and minerals of Australia

The relief of the continent and, especially, its peculiar formation, influenced the amount of minerals found here. The Australian mainland is very rich in minerals and is one of the largest raw materials “pools” on the planet.

The regional link of certain resources is clearly visible on the map of Australia's mineral resources. In a condensed form, this can be presented as a table from which you can understand which Australian mineral resources are concentrated in a particular region of the mainland:

Region of Australia	Minerals
Western Australia	gold (it should be noted that there are gold deposits throughout the continent, but compared to the western ones they are much poorer); polymetallic ores; uranium ores; bauxite (deposits on the Arnhem Land and Cape York peninsulas, and near the Darling Ridge; iron (large iron deposits are also found in South Australia; the largest ore deposit, Iron Knob, is located here);
Central Australia	polymetallic ores; manganese; Opal deposits are being actively mined in the Lake Eyre area.
Eastern Australia	coal deposits (brown and hard coal; Australia contains more than 9% of the world's total coal reserves);

Fig 3. Map of Australia's mineral resources

Many deposits in Australia lie at shallow depths, which is why they are mined using open-pit mining.

Australia currently ranks:

• 1st place in iron ore mining;
• 1st place in the extraction of bauxite, lead and zinc;
• 2nd place in uranium production;
• 6th place in coal production.

It should be noted that Australia currently ranks first in the world in diamond mining. The country's largest deposit is located in the Lake Argyle region.

Among other things, Australia is actively working to develop deposits of clay, sand and limestone.

What have we learned?

The characteristics of the relief of Australia are simple. There are practically no high mountains on this continent; in area this continent is more like a large island, the coastline is quite flat, and a large area of ​​the continent is occupied by plains and plateaus. But despite this, Australia is the world leader in raw materials.

Test on the topic

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Goals and objectives of the lesson:

To form in students an idea of ​​the physical-geographical position and relief of Australia.

Continue the formation of a method for determining the mainland's GP.

Introduce the history of the discovery and exploration of the continent.

Develop the ability to work with geographical maps and textbook text.

Equipment: “Physical map of Australia”, “Structure of the earth’s crust”, computer, projector, presentation, cards.

Lesson type : learning new material.

During the classes

1.Organizational.

Student definition topics, lesson objectives (slides with images of Australian animals, corals are shown)

? It is located below us.
They're obviously walking upside down there,
It's a year turned inside out.
The gardens there bloom in October,
It's summer there in January, not in July,
Rivers flow there without water
(They disappear somewhere in the desert).
There are traces of wingless birds in the thickets,
There cats get snakes for food,
Animals are born from eggs,
And there dogs don’t know how to bark.
The trees themselves climb out of the bark,
There rabbits are worse than a flood,
Saves the south from the northern heat,
The capital has no population.

? - the country is the opposite.
Its source is on the London pier:
The road was cleared for predators
Exiles and convict people.
? - the country is the opposite.

II. Activation of knowledge and skills.

1. According to what plan are we exploring the mainland?

2.Remember the FGP characteristics plan

3. What phenomena occur at the boundaries of lithospheric plates?

4.What is the platform?

5.What is relief?

6.What landforms do you know?

7.What are the heights of plains? What color are they indicated on the map?

8.How are mountains divided by height?

Ill. Learning new material.

Teacher's opening speech.

Australia is one of the most unique continents. After all, in fact, Australia is indeed the very, very, very continent. For example this:

the smallest continent. Australia's area is 9 million km 2 , several times smaller than Eurasia (54 million km. 2 )

the most remote continent, which is why Australia was discovered later than all other continents.

lowest continent. On 95% of its surface the altitude does not exceed 600 m above sea level.

the calmest continent. There are no active volcanoes here.

the driest continent, because most of its territory is occupied by deserts

the most amazing continent in terms of its organic world, because many species of animals and plants live there that cannot be found anywhere else on the globe.

The most sparsely populated continent, the population of the continent is comparable to the number of the largest cities in the world: 17 million people live in Australia,

Australia is the only country in the world that occupies an entire continent!

Physico-geographical location of the continent.

Exercise 1. Using the plan “Characteristics of the FGP of the continent” (see appendix p. 311) and the physical map of Australia, describe the FGP of the continent.

History of the discovery and exploration of the mainland

Task 2 . Read the text and complete the tasks.

History of discovery Andcontinental exploration. E Even ancient geographers suggested the existence of an unknown southern land south of the equator. Yes, still on the mapPtolemy ( IIV. n. BC) a vast area was mapped in the southern hemisphere, which was called“Terra Australian incognito”- “Unknown South Land" The first Europeans to visit the unknown continent were the Dutch. navigatorWillem Janszon crossed without noticing the Strait, later called Torres Strait.1606 HispanicLuis Vaez de Torres discovered the northernmost tip of the Australian Cape York Peninsula, and named the Torres Strait separating New Guinea from Cape York.In 1642Abel Tasman explored the northern and northwestern shores of the mainland and discovered in 1642. the island later named after him - Tasmania. Subsequently, A. Tasman walked around Australia from the south and east and established that it was an independent continent. For a long time, the Dutch kept their discoveries secret. Only in 1770 did the English navigatorJames Cook explored the eastern coast of Australia and finally rejected the legend about the existence of a large southern continent and declared it an English possession. Australia dates back to January 26, 1788, when a “penal colony” for criminals was organized here. PAn army of 1,000 English settlers, most of whom were convicts, descended on the deserted wild coast and founded the first settlement - Sydney.Subsequently, free settlers appeared on the mainland. The conquest of the mainland began, accompanied by the extermination of the indigenous population. A hundred years later, most of the aborigines were exterminated. The remaining indigenous people were driven to the interior desert territories of the mainland.INXIXV. More than a dozen expeditions were equipped to explore the interior desert regions of the continent. For the first time in 1860, an Englishman managed to cross Australia from south to northR. Berk . The expedition went from the city of Adelaide to the Gulf of Carpentaria.When deposits of silver and gold were found on the mainland, England declared Australia its colony.The development of Australia was also facilitated by the presence of convenient pastures on the mainland for cattle breeding. By the endXIXV. basically the exploration of the mainland was completed.Currently, Australia is a federal state, the capital is Canberra, the official language is English.

1. fill out the table:

Traveler name

Years

What is done

K. Ptolemy

2nd century AD

Mappedit has a vast territoryin the southern hemisphere under the name "Unknown Southern Land"

Willem Janszoon

1605

Crossed the Strait, later called Torres Strait, without noticing.

Luis Vaez de Torres

1606g

He discovered the northernmost tip of the Australian Peninsula, Cape York, and named the Torres Strait separating New Guinea from Cape York.

Abel Tasman

1642

He explored the northern and northwestern shores of the mainland and discovered it in 1642. the island later named after him - Tasmania. ZThen, he walked around Australia from the south and east, and established that it is an independent continent

James Cook

1770

Explored the eastern coast of Australia and declared it an English possession.

R. Burke

1860

Crossed Australia from south to north for the first time

2. Find geographical names on the map associated with the names of explorers and travelers.

Relief and minerals of Australia.

At the base of the continent lies the ancient Australian Plate. The East Australian fold belt adjoins it from the east. This geological structure is reflected in the topography of the continent. Most of it is occupied by plains. The flat part of the continent is divided into two parts - the Western Plateau and the Central Lowland. Maximum height western lowland part - Mount Liebig (1524 m), and in the area of ​​Lake Eyre there is the lowest point of the mainland with an altitude of 12 m below sea level.IN share east coast within the folded region stretches the low, heavily destroyed Great Dividing Range. The eastern slopes of the mountain ranges are very steep, while the western slopes descend in steps towards the Central Plains. The highest point in Australia is Mount Kosciuszko (2228 m). Also along the eastern coast of Australia is an amazing and beautiful creation of nature - the Great Barrier Reef. James Cook's sailing ship Endeavor became the first ship to navigate the narrow strait between the Great Barrier Reef and the mainland coast.

Task 3. Using the physical map of the continent and the map of the structure of the earth's crust, compare the western and eastern parts of the continent

Table Comparative characteristics of the western and eastern parts of the continent

Signs of comparison

Western part of the mainland

Eastern part of the mainland

Tectonic areas

Nature of the relief

Minerals

Highest point

IV. Fastening:

Guys, today we met another continent - Australia.

Let's remember what epithets with the word “most” can be applied to Australia?

Name the researchers of Australia.

Name the main features of the relief of Australia.

Exercise 4 . Work with contour maps (lists of nomenclature are distributed to students along the coastline of the mainland, it is proposed to mark objects on the map)

Seas - Tasman, Timor, Coral, Arafura.

Straits – Torres, Basov, Cook

Gulfs – Great Australian, Carpentaria.

Islands: Tasmania, New Zealand, New Guinea.

Peninsulas – Cape York, Arnhem Land,

Capes: York10*, 41` S, South East Point (South-East) 39* 11` S,

Stip – Point 113*, 05`E, Byron153*, 39`E

Summing up the lesson, grading.

V. Homework: paragraph 35, task 2 page 150

A little over 200 years ago, Australia was sparsely populated by Aboriginal people. In 1788, the first European settlers arrived in Australia with the First Fleet, created in 1786 by order of Lord Sydney to transport 750 prisoners. In total, there were 1,487 people on the ships, of whom 1,030 remained in Australia. The country's population is now about 19 million.

The capital of Australia is Canberra. Australia is divided into 6 states, two internal territories and 7 external ones: Victoria (VIC) capital Melbourne (Melbourne) New South Wales (NSW) capital Sydney (Sydney) South Australia (South Australia) , SA) capital Adelaide Queensland (Queensland, QLD) capital Brisbane Western Australia (WA) capital Perth Tasmania (TAS) capital Hobart Federal Capital Territory , ACT) capital Canberra Northern Territory (NT) capital Darwin External territories: Norfolk Island, Cocos Islands, Christmas Island, etc. POPULATION Indigenous people aborigines, equatorial and europioid races.

Anthropologists classify them as the Australoid race. The indigenous population is small, accounting for about 1% of the mainland's inhabitants. IN ethnically The aborigines are divided into numerous tribes that speak different languages. The main modern population is Anglo-Australian, descendants of colonists from Great Britain and Ireland, as well as emigrants from Europe and Asia who moved here. Official language Australian English. The population is about 17 million people. The average population density is 2 people per km. sq. Most of the population lives in large cities in the southeast of the continent (Melbourne, Sydney, Canberra, etc.). The Commonwealth of Australia is the only state in the world that occupies an entire continent. The capital of the state is Canberra, the cultural and administrative center of Australia. The 1996 census showed that there were 17,892,423 people living in Australia at that time, an increase of 6.2% since 1991.

Australia's population is aging; the average age is 34 years old, and 12.1% of the total population is aged 65 years or older. Of the total population, 73.9% were born in Australia, and of the rest, 36.2% came from England. There are immigrants from New Zealand and Ireland, but the majority (after England) are from Italy, Vietnam, Greece, China and Germany. The number of Aboriginal people rose by a third from 265,458 in 1991 to 352,970 in 1996. Of these, 55.8% were counted in the states of New South Wales and Queensland. Among the population of the Northern Territory, Aboriginal people make up 23.7%. Everywhere except the Northern Territory, women (50.5%) outnumber men (49.5%). LANGUAGE English (official). Due to big amount immigrants, you can hear all varieties and accents of English, as well as Chinese, Italian, Russian, Greek... plus many dialects of Australia's indigenous Aboriginal people. CLIMATE The seasons are opposite to European ones: the hottest time is in December and January, the Australian winter in June and August THE HIGHEST, LOWEST, BIGGEST IN AUSTRALIA... The highest mountain is Mount Kosciuszko 2,229 meters. The highest point of Heard Island's Mawson Peak is 2,754 m. Australia is the lowest continent in the world, with an average height of only 330 meters.

The lowest point is Lake Eyre, 15 meters below sea level. The southernmost point of the mainland is South Point, Wilson's Promontory, south of Melbourne. South East Point in Tasmania is the southernmost point of the continent with the exception of Antarctica. The longest river Murray (Murray River) and its tributary river. Darling River. Together they stretch for 3,370 km, and their basin covers more than a million square kilometers, that is, 14% of the entire territory of Australia. The largest state is Western Australia, with an area of ​​more than 2.5 million square meters. km. The largest island is Australia itself, followed by Tasmnia, and Melville Island, located near Darwin and occupying 5,786 square meters. km The smallest state is Tasmania. The highest temperature, +53 C, was recorded in the state of Queensland in 1889.

Geology of Australia

Australia is the smallest continent. Its area is 7631.5 thousand km2, which is about 2/3 of the area of ​​Europe. The northernmost point of the continent, Cape York, is located at 10°41" S, the southernmost point is Cape South-East at 39°11" S. w. The continent extends from west to east for 4100 km (from Cape Steep Point at 113°05" E to Cape Byron at 153°34" E), from north to south the greatest length of land is only 3200 km. The coastline is poorly dissected. There are only two large bays: Carpentaria and Great Australian. The Bass Strait separates the island of Tasmania from the mainland.

Australia, the island of Tasmania and other small islands in the Pacific and Indian Oceans form the territory of the Commonwealth of Australia. The east coast of Australia is accompanied by the Great Barrier Reef, which stretches almost 2000 km from Cape York to the tropics. Its width in the north is about 2 km, in the south it increases to 150 km. It is separated from the shore by a lagoon, up to 50 m deep, also expanding to the south. The Great Barrier Reef is cut with narrow passages that allow ocean-going steamships to enter from open ocean into quiet coastal waters. The relief of Australia is simple and resembles that of Africa. The western half of the continent is occupied by the Western Plateau, adjacent to it is a wide strip of the Central Lowland, stretching from the Gulf of Carpentaria to the Indian Ocean. On the eastern edge of the continent there is a narrow strip of mountains called the East Australian Mountains. The nature of Australia has many features that distinguish it from other parts of the globe. Australia is, first of all, a continent of relics. Relic species plants and animals are characterized by high endemism, extreme antiquity and have been preserved on the Australian landmass due to its long-term isolation. On the continent, vast ancient leveling surfaces, armored with lateritic crusts and causing the flat nature of the relief, remained undivided by erosion. Traces of the former watering of the now desert and semi-desert areas have not disappeared. On the other hand, Australia has no young folded mountains, no active volcanoes and no modern glaciation. All this is in connection with the geological history of the continent and with climate fluctuations in the geological past and gives the nature of the continent a deep originality. Geographical location and modern features climate determine the widespread distribution of tropical desert landscapes within Australia. The northern edge of the continent is occupied by savannas and woodlands, the southern by landscapes of the subtropical type: forests on the humid southwestern and southeastern edges and landscapes of savannas, steppes and semi-deserts in the drier inland areas.

The mountains stretching along the eastern edge of the continent trap moist winds from the Pacific Ocean and limit the spread of damp-forest landscapes to a narrow strip of coastal lowland and windward slopes.

Minerals of Australia

The geological structure of Australia is the simplest compared to other continents. It contains the Precambrian platform and the Hercynian fold belt. The Precambrian platform makes up 2/3 of the continent's Western Plateau and almost the entire Central Lowland. The western part of the platform represents the anteclise of the ancient basement, where Precambrian crystalline rocks and, to a lesser extent, Proterozoic and younger sedimentary formations are exposed. The eastern part of the syneclise platform of the ancient foundation. The Precambrian basement here is lowered and covered by a thickness of Mesozoic (mainly Cretaceous), Paleogene and Neogene marine and lacustrine sediments. Hercynian folded structures make up the eastern mountain belt of the continent. In addition to Paleozoic folded-sedimentary formations, volcanic and intrusive rocks of all ages take part in its structure. The Australian platform was subject to faulting and oscillatory movements that occurred in connection with tectonic movements in the geosynclines that framed it from the west and east. The Western Australian geosyncline, which formed in the Precambrian, was part of a huge geosynclinal zone that framed the Archean and Proterozoic land cores in the southern hemisphere. Lower Paleozoic folding and oscillatory movements that occurred in this zone created land connections between the Precambrian platforms of Australia, Southeast Asia and Africa, which were preserved in Paleozoic era and in the first half of the Mesozoic. The splits that led to the separation of Australia from Africa and Southeast Asia occurred only in the Cretaceous period.

In the East Australian, or Tasmanian geosyncline, the Lower Paleozoic folding formed a mountainous country, which in the west adjoined the leveled Australian platform, and in the east went beyond the modern contours of the continent. However main role In the formation of the mountains, the Upper Paleozoic folding took place, as a result of which a huge section of the mountainous land of the Tasmantis, stretching in place of the Tasman and Coral Seas, was raised from under sea level. Since the end of the Paleozoic, the landmass of Tasmantis has experienced slow fluctuations; at the beginning of the Mesozoic, troughs captured the Central Lowland. They led to the ingression of the seas and to the formation of vast lake basins in which limestone and clayey-sandy strata were deposited. Seas and lakes have long isolated Australia's western flattened landmass from its eastern mountainous country. The general uplift of the continent at the end of the Cretaceous caused the retreat of the seas and the shallowing and drying out of lakes. The northern and eastern margins of the Precambrian structures of Australia and the Hercynian structures of Tasmantis were framed by an Alpine geosyncline.

Tectonic movements in it led at the end of the Cretaceous to the loss of land connections with Southeast Asia and the New Zealand structures that survived the submersion. Powerful folding in the Alpine geosyncline occurred in the Neogene. Were erected high mountains New Guinea, New Zealand and the mountainous archipelagos of islands in between. On the hard bases of Australia and Tasmantis, folding was reflected by faults, movements of blocks along them, intrusions, volcanic activity, slow flexures and uplifts. The western fault edge of the continent rose; On the Tasman Land, the Kimberley horst massif outlined by faults stood out. The Flinders Lofty horst ranges were separated from the southwestern edge of the Western Plateau by the Lake Torrens graben. The most significant changes in topography, as well as in the size and shape of the continent, occurred in the east. Along fault lines, a significant part of Tasmantis sank to the bottom of the Pacific Ocean, its western edge, preserved from immersion, rose high, which determined the orographic expression of the East Australian Mountains. Their ancient rocks were overlaid with basalt covers, occupying especially large areas in the central and southern ridges. During the Quaternary period, the marginal parts of the continent continued to slowly fluctuate. The final separation of Tasmania and New Guinea from the mainland took place; the subsidence of individual mountainous sections of the coast created finely indented rias coasts on the island of Tasmania, in the northwest and in the east of the mainland. The nature of the relief of Australia is determined by the antiquity of its constituent structures and long-term peneplanation. The latter led to the leveling of vast territories, so that the relief, first of all, is struck by its amazing monotony: the continent is a plateau with average height 350 m, i.e. It is the lowest part of the land after Europe. From the previous higher levels, flat-topped island mountains (in places where sedimentary formations occur) and peaked massifs (in places where crystalline rocks occur) have been preserved. The largest area is occupied by the leveling surface created during the period from the end of the Cretaceous to the Neogene, the so-called Great Australian Peneplain. It has a height of 300-500 m on the Western Plateau, does not rise above 200 m in the Central Lowlands and rises to 700-1500 m in the East Australian Mountains, where it can be traced in the same levels of flat-topped massifs. The wide distribution and good preservation of planation surfaces and, in particular, the Australian peneplain, are explained by the slowness of vertical land movements and the weak degree of dissection of the relief in a predominantly desert climate, as well as the armoring effect of protective crusts.

Ferrous and siliceous protective crusts have been preserved mainly since the Neogene, when the necessary climatic conditions for their emergence were very hot and seasonally humid conditions. The formation of limestone, gypsum and sulfate protective crusts began at the end of the Neogene in a dry and hot climate and continues now in the interior of Australia. Short-term humidification and cooling during the pluvial epochs of the Quaternary period led to the formation of erosional relief forms (river valleys, lake basins, etc.), preserved in modern desert areas. Glacial sculptural forms, as well as the relief of glacial accumulation, are characteristic only of the Australian Alps, the only region where, in addition to the island of Tasmania, there was Quaternary glaciation. The peculiarities of the tectonic structure of Australia make it possible to distinguish three structural and morphological provinces on the mainland: the Western Plateau, the Central Lowland and the East Australian Mountains. The western plateau, which generally coincides in its outline with the anteclise of the Precambrian basement, represents a weakly dissected surface of the Great Australian peneplain with an average height of 300-500 m. On its eastern edge rise the crystalline ridges of the MacDonnell and Musgrave ranges, prepared by denudation (Mount Widroff, 1594 m, the highest point of the Western Plateau). At the western edge there are extensive flat-topped remnant massifs (Hamersley Ridge, etc.). The southwestern edge of the plateau, steeply falling to a narrow coastal lowland along the fault line, is called the Darling Ridge. In the north-west the plateau is framed by the Kimberley horst massif, in the north it ends on the Arnhem Land Peninsula.

Huge areas in the interior are occupied by sandy and rocky deserts. Sandy deserts The Great Sandy and Great Victoria Deserts lie on the northern and southern slopes of the Western Plateau and are separated by the rocky Gibson Desert. In the southwest, lake basins have been preserved as evidence of the wet eras of the Quaternary period. In the south, the Nullarbor Karst Plain stands out. Central lowland. The prerequisite for its formation was the trough of the eastern margin of the ancient Australian platform, the subsidence of part of the Caledonian folded structure, as well as subsequent marine and lacustrine regimes. Thicknesses of marine and lacustrine sediments hid the unevenness of the ancient relief, which appears only in the form of weakly expressed hills on the outskirts of the lowland. Its middle part, the so-called Central Basin, lies in the area of ​​Lake Eyre, 12 m below sea level. This is the lowest place in Australia. In the western half of the basin there are deserts that continue the desert belt of the Western Plateau.

The south-eastern part of the Central Lowlands is occupied by aggradational plains crossed by Australia's largest rivers, the Murray and Darling. In the lower reaches of the Murray, to the west of the river, the area of ​​the Flinders Lofty horst-block ridges stands out. East Australian Mountains. For a long time they were called the Australian Cordilleras, however, in terms of the type of relief they differ sharply from the Cordilleras of both North and South America. These are ancient (mostly Hercynian in age) horst-block mountains, already heavily destroyed, with average heights of about 1000 m, mostly flat-topped. Paleogene and Neogene faults and faults split them into separate ridges and massifs. Faulting along the east coast of Australia has caused the eastern slopes to become steep; the gentler western slopes descend into the Central Lowlands in rolling foothills (downs). The outpourings of basalts that accompanied the splits left their mark on the shapes of the ridges in many places. Stepped plateaus are associated with linear eruptions, volcanic cones are associated with eruptions of the central type. In the highest mountain range, in the Australian Alps (Kosciuszko Peak 2234 m), traces of Quaternary glaciation have been preserved: cirques, troughs, glacial lakes. Karst is developed in the limestones that make up the peaks of the Blue Mountains and some others. Minerals. Due to the weak development of sedimentary covers, Australia is characterized by a significant predominance of ore minerals over nonmetallic ones. The areas of the most active metallogeny are concentrated along the western margin of the continent and in the southeast, in the contact zones of platform Precambrian and geosynclinal Paleozoic structures, as well as in the East Australian Mountains, in folded Caledonian and Hercynian structures. Australia has significant reserves of gold, non-ferrous metals and iron ores. The leading role among ore minerals is played by gold, the main deposits and mining areas of which are concentrated in the southwest of Western Australia (Kalgoorlie, Coolgardie, etc.), in the state of Victoria (Bendigo, Ballarat) and in the northeast of Queensland (Charters Towers to the south). -west of Townsville, etc.). The most significant mining and reserves area is in the southwest, covering a wide area between the Murchison River and the city of Dundas. Non-ferrous metal ores are concentrated mainly in eastern Australia. The largest deposit (and main mining area) of copper ore is located on the island of Tasmania (Mount Lyell); large deposits copper ores available and developed in Queensland (Mount Morgan, Mount Isa). Australia has very large reserves of polymetallic ores, zinc and lead, as well as silver.

New South Wales ranks first in reserves and production of polymetallic ores. The state's Broken Hill deposit is one of the largest in the world. Significant amounts of silver and zinc are mined in the north-east of Australia in Queensland (Mount Isa), as well as on the island of Tasmania. It is also necessary to mention the very large reserves of tantalum and niobium, the industrial deposits of which are concentrated in Western Australia (Pilbarra). Deposits of uranium ore ores have been explored and exploited in South Australia (Mount Painter and Radium Hill) and in the Northern Territory (Rum Jungle, etc.). The main mining area for iron ore deposits is near Iron Knob in South Australia, although larger reserves than at Iron Knob are found on the islands of Coolen and Coatoo in Yampi Bay (north of the Fitzroy River mouth), as well as in the Murchison River basin. There is little or no mining in these areas at present due to the difficulty of transporting ore to the New South Wales smelters. By reserves coal Australia ranks first among countries southern hemisphere. The largest coal basin (Permian age) is located in New South Wales and occupies a very advantageous geographical position, stretching in a strip of 250 km along the coast of the Tasman Sea. The thickest seams of high-quality coal are concentrated in the area of ​​the cities of Newcastle (mainly) and Sydney. The second largest basin is located in Queensland (in the Brisbane and Claremont areas). The coals of this basin are Permocarbonic in age. Brown coals (Tertiary age) are mined by open pit mining in the state of Victoria, in the vicinity of Melbourne; There is information about the discovery of new brown coal reserves near Adelaide. Oil exploration, which is currently being intensively carried out, has not yet yielded practical results. The main reason for the lack of oil on the mainland is the paucity of basins with sufficient thickness of marine sedimentary rocks in which oil could accumulate.

Climate of Australia

Australia lies in latitudes ranging from subequatorial in the north to subtropical in the south, and only the island of Tasmania lies almost entirely in the temperate zone. In accordance with this geographical location One of the main factors influencing the climate of the continent is the high total solar radiation, reaching 140 k/cal per cm2 per year in the north-west. Compared to South Africa and South America, south of the equator, Australia is more sprawling from west to east. With a weakly dissected coastline, this causes constantly high temperatures in the interior and gives the right to consider it the hottest part of the land in the southern hemisphere. The climate of most of the continent is continental.

Sea air, which sometimes penetrates far into the deep regions from the north and south (favored by the absence of orographic barriers), quickly warms up and loses moisture. The East Australian Mountains trap moist winds from the Pacific Ocean flowing from the western periphery of the South Pacific High and separate the oceanic from the continental sectors. The climate of these narrow coastal sectors is influenced by the warm East Australian Current. The Darling Ridge also limits the narrow oceanic sector of the Mediterranean climate to the southwest. The coastal strip in front of it is somewhat cooled by the weakly expressed cold Western Australian Current. The coast north of the Darling Range is exposed to winds flowing from the eastern periphery of the South Indian High and the summer monsoon. The latter, along with winter cyclones, bring with them a small amount of precipitation, so the deserts on the western edge of Australia are replaced by semi-deserts. From December to February, the continent warms up greatly, especially its northern and northwestern parts; This is the hot season of the year. In the north of the Western Plateau and almost the entire northern half of the Central Lowland, the average air temperature is above 30°C. In the extreme south there is an isotherm of 20°C. Due to the strong heating of the land above it, low atmospheric pressure is established - the Australian minimum. Areas of high pressure over the Indian and Pacific oceans at this time of year move south and, connecting, capture the southern edge of the continent. From the northwest to the interior low pressure humid equatorial air is drawn in, releasing heavy precipitation only on the coast. The Arnhem Land and York peninsulas receive more than 1000 mm of rainfall per year. In the inland regions, these rains, although they determine the summer maximum precipitation north of the Cape line of the North-Western city of Sydney, are generally not very effective South of 19-20° S. w. precipitation falls no more than 300 mm, and semi-deserts and deserts dominate.

Southeast and southern winds are drawn from the south into the low pressure area. But they come from higher latitudes (from an area of ​​high pressure) and do not produce precipitation. Therefore, the summer in southern Australia is very dry: in Perth (in the southwest), out of 850 mm of annual precipitation, only 32 mm falls in the summer, i.e., about 4% of the total. Passing over the hot land, winds from the ocean quickly warm up; the southern deserts of the Western Plateau and the southern Central Lowlands experience hot weather (the average temperature of the hottest month in Coolgardie is 25.3 ° C). The coastal strip is naturally somewhat cooler: in Perth, the average temperature of the hottest month is 23.3°C. A special weather regime is established at this time of year on the east coast of the mainland. Winds from the Pacific Ocean (carrying equatorial air north of 19° S, tropical air to the south, but both are humid and warm), encountering a mountain barrier, produce abundant orographic rains. In Mackay, for example, out of 1910 mm of annual precipitation in December, February falls 820 mm (43%), in Sydney, out of 1230 mm of annual precipitation, 250 mm (20%). The weather is hot and humid. The average summer temperature in Sydney is 22°C, in Brisbane 25°C, in Mackay 28°C. During the cool season of the year (June-August), the mainland cools noticeably. On the northern coast, average monthly temperatures decrease by 5-6°C; in other parts of the mainland by 10-12°C. The 15°C isotherm passes this season slightly north of the southern tropic, and the 10°C isotherm runs along the Bass Strait, separating Tasmania from Australia. High pressure is established over the mainland, the Australian High. The northern coast is influenced by dry and hot southeasterly winds of the northern periphery of the Australian High and receives almost no precipitation. There is also no rain in the interior parts of the continent. Along the south coast and over Tasmania, westerly transport of sea air dominates this season temperate latitudes. In the zone of the polar front, which forms between temperate and tropical air, unstable weather occurs with cyclonic rains, therefore, south of 32° S. there is a winter maximum precipitation. In Perth in June-August 470 mm (55%) of 850 mm of annual precipitation falls. The only exception is the south-eastern edge of the mainland, where in winter relatively cold south-westerly winds blow along the eastern periphery of the Australian High. In this regard, even in Sydney in winter there is slightly less rainfall than in summer. From 32° south w. to the southern tropic along the eastern coast the winds blow south, and north of the tropic southeasterly winds blow.

They reduce temperatures in Brisbane to 14°C and in Mackay to 16°C and bring relatively little moisture: Mackay receives only 130mm of rain from June to August. Depending on the annual cycle of humidification, thermal characteristics and distribution of baric systems and air masses in Australia, the following climatic zones and regions are distinguished: the subequatorial climate belt of Northern Australia (up to 20° S) with constantly high and even temperatures throughout the year (about 25° C) and the alternation of wet summer and dry winter seasons; zone of tropical (trade wind) climate (between 20° and 30° S) with two regions. The first region of continental desert and semi-desert climate stretches from the East Australian Mountains to the Indian Ocean; The second region of the maritime trade wind climate occupies a narrow strip of the Pacific coast and is characterized by hot and very humid summers and a warm and less humid subtropical climate. southern part Australia and the northern coast of Tasmania. Several regions are also distinguished in this belt: the southwest is characterized by a Mediterranean-type climate with hot and dry summers and cool, wet winters; for the southeast, a subtropical monsoon climate with a summer maximum precipitation; Between them there is a region of continental subtropical climate with a winter maximum of precipitation and rare summer convective rains. The mountain climate of the Australian Alps with the most fully developed altitudinal zonation should be distinguished as a special subregion; The temperate climate zone includes only Tasmania, which is characterized by a strong oceanic influence - large amounts of precipitation brought by the prevailing westerly winds during the year, and moderate temperatures.

Vegetation, soils and fauna of Australia

Australia, separated since the Cretaceous from southern continents and Southeast Asia, has an extremely unique composition of flora and fauna. Its flora is very poor in species (in total there are up to 1200 species higher plants ) and is highly endemic (up to 75% of plant species are endemic). In view of this, Australia, together with Tasmania, is designated as an independent Australian Floristic Region. The Australian flora contains representatives of the Antarctic flora, common to those that currently live in South America and New Zealand (southern beeches Nothofagus spp., some conifers) and with the Cape flora of South Africa (representatives of the family Proteaceae, etc.). This is explained by the existence of pre-Cretaceous land connections, passing, in particular, between Australia, South America and Africa through the Antarctic continent. In the Neogene, the Australian land was twice connected with the Malay Archipelago and New Guinea, had periodic connections with New Zealand, the Bismarck Archipelago, the Solomon and other islands of Oceania, as a result of which representatives of the Malesian flora migrated to the mainland, its more ancient Melanesian elements (from the small archipelagos of Oceania) and more young (from New Guinea). The flora of Malesia includes species of ficus, pandanus, some palms, vines, the so-called candle tree (Aleurites moluccana); its distribution is limited mainly to the northern and eastern regions of Australia. The endemic flora of the mainland developed from the mid-Cretaceous period in two centers - the southwest and southeast. It is most characterized by eucalyptus trees (Eucalyptus, more than 600 species and subspecies), phylloid acacias (Acacia, 280 species), and banksias (Banksia spp.) , narrow-leaved casuarinas (Casuarina spp.) and grass trees (Xanth-orrhoea preisii). Both formation centers were separated by sea and lake basins until the Quaternary period, and currently an ecological barrier of inland deserts lies between them. The xerophytic flora of the deserts arose from hygro- and mesophytes mainly of northern and eastern Australia, which migrated into the interior during the pluvial epochs of the Quaternary period. The vegetation cover of the continent reflects both the paleogeographical features of its formation and modern hydrothermal conditions. The largest area of ​​the vast interior desert regions is occupied by the formation of grasslands. Based on the predominance of turf grasses spinifex (Spinifex spp.) and triodia (Triodia spp.), the eastern inland desert is called spinifex, and the western desert is called triodic. In the north of Australia, grasslands are replaced first by mulga-scrub thickets of thorny acacias (Acacia aneura), and then by savannas with umbrella acacias, single succulent Gregory baobab (Adansonia gregorii) trees and eucalyptus trees.

On the northern coast, which receives not only regular but also fairly abundant summer precipitation, savannas alternate with eucalyptus woodlands, and along the river valleys there are dense gallery forests, very rich in species composition. In the south of the mainland, the grass desert gives way to a wide strip of mulga-scrub, and where it is wetter, thickets of mally-scrub bush eucalyptus (Eucalyptus dumosa), etc. In the south-west of Australia, which receives regular winter rainfall, the mally-scrub gradually turns into dry eucalyptus forests covering windward slopes of the Darling Range. The windward Pacific slopes of the East Australian Mountains are covered with dense forests; the dry western slopes are covered with open forests with patches of savannahs. To the north of 19° S, on the windward slopes, subequatorial permanently moist forests grow, similar to the gallery forests of the northern coast. There are many palm trees, ficuses, laurel trees, At altitudes above 1000 m, araucarias and tall bamboos appear. Between 19° and 30° S, tropical forests are common, dominated by eucalyptus trees, and the number of species of Malesian flora decreases sharply. South of 30° S. w. the mountain slopes are dressed in monsoon subtropical forests Their lower zone is dominated by tall-stemmed eucalyptus trees, higher in the undergrowth of eucalyptus trees tree ferns appear, the upper forest boundary (in the Australian Alps) is formed by evergreen beeches (Nothofagus Cunninghami) and snow gum eucalyptus (Eucalyptus coriacea). The woodlands of the western slopes of the East Australian Mountains consist of eucalypts, without undergrowth, with a dense ground cover of grasses and dicotyledons and callitris cupressiformis. Since the beginning of colonization in Australia, huge tracts of forests have been destroyed and destroyed by fires. This greatly deteriorated the natural water supply of many vital areas.

Many pasture lands have been trampled and depleted, retaining only cereals of low nutritional value. The destruction of vegetation contributes to soil erosion and drift. In Australia, all types of soils characteristic of the subequatorial, tropical and subtropical zones are distinguished in a regular sequence. In the interior desert regions, primitive rocky and clayey soils are widely developed. Large areas are covered by sands, mostly fixed. To the north, primitive soils are surrounded by a semi-ring of tropical semi-desert reddish-brown soils, clayey and loamy. In the west they are distributed all the way to the coast of the Indian Ocean, in the north and east they turn into red-brown soils of deserted savannas.

The latter give way to the red soils of tall grass savannas with their mountain varieties on the Kimberley Plateau and the Arnhem Land Peninsula. Along the northern coast of the mainland in places of high standing groundwater There are swamp soils and patches of podzolized laterites, and at the mouths of tidal rivers there are soils of mangrove swamps. In the south, in the subtropical frame of the interior deserts of the continent, from the coast of the Indian Ocean to the middle reaches of the Murray and Darling, mainly gray soils and gray-brown soils of subtropical semi-deserts and steppes are developed. As climate humidity increases, they become zonal for Mediterranean conditions brown soils, but in the southwest near the Indian Ocean coast brown soils give way to relict red soils and yellow soils, preserved from the more humid and warm climate of the Neogene, under which lateritic crusts are widespread. On the Murray-Darling plains, where the winter maximum precipitation is still pronounced, there is also a strip of brown soils, turning closer to the foothills into the red soils of subtropical savannas. In the East Australian Mountains north of 28° S. w. Mountain forest brown soils are developed; to the south they give way to podzolized red soils and yellow soils and mountain forest brown soils, giving way (at the tops of the Australian Alps) to mountain meadow soils. Even greater endemism and relictness compared to the flora are manifested in the fauna of Australia and adjacent New Guinea and Tasmania, which constitute the Australian zoogeographic region. Representatives of the Mesozoic and Tertiary fauna have survived to this day (for example, the majority of marsupials living on Earth) and, on the contrary, higher mammals are almost absent. It is believed that marsupials and other lowly organized animals entered Australia in the Cretaceous period before its separation from Eurasia through land connections through the Malay Archipelago. These connections ceased by the time of the appearance of highly organized animals, in particular carnivores. The absence of predators contributed to the unhindered evolution of marsupials, which reached their highest development in the Neogene and at the beginning of the Quaternary period. It was at this time that a suborder of two-incisor marsupials, characteristic only of Australia, appeared (the family of kangaroos, wombats, cuscus, etc.), standing at a higher level of development compared to their multi-incisor ancestors. The development of marsupials proceeded along the line of convergence with higher mammals, that is, along the line of producing something similar to them life forms. Therefore, marsupials have developed common life types with higher mammals living in the same environmental conditions.

The most numerous family of kangaroos is an analogue of artiodactyls, the wombat family is close to rodents, the cuscus family is similar to flying squirrels, etc. Kangaroos, wombats, cuscuses different types live throughout Australia. The predatory marsupials wolf and devil live only on the island of Tasmania, where the marsupial koala bear is also found. In Australia, monotreme oviparous mammals have been preserved - the echidna (in desert and semi-desert areas) and the platypus (in the southeast). The echidna is a terrestrial animal that feeds on ants and termites, while the platypus water image life and is found in river backwaters. Of the higher mammals, Australia is home to endemic bats and rodents, as well as the wild dog dingo, which came to the mainland during human settlement. Among the birds that characterize Australia are the endemic emus (living mainly in Western Australia), cassowaries (only in Northern Australia), the cockatoo subfamily of parrots, lyrebirds, birds of paradise, weed chickens (laying eggs in heaps of plant debris) and black swans (in the south -western Australia). There are many in Australia poisonous snakes, lizards (including frilled lizard). Two species of crocodiles live in Queensland rivers. Of the fish, it is necessary to name the ancient lungfish ceratoda, the range of which is also limited to the rivers of Queensland. The fauna of arthropods is very rich (many mosquitoes, flies, scorpions and poisonous spiders). During colonization, large and small cattle, rabbits (incredibly prolific), foxes, and many European birds were brought to Australia and became well acclimatized.

Flora of Australia

Since the Australian mainland long time, starting from the mid-Cretaceous period, was isolated from other parts of the globe; its flora was very interesting and unique. Of the 12 thousand species of higher plants, more than 9 thousand are endemic, that is, they grow only on the Australian continent. Among the endemics are many species of eucalyptus and acacia, the most typical plant families of Australia. At the same time, there are also plants here that are native to South America (for example, southern beech). South Africa (representatives of the Proteaceae family) and the islands of the Malay Archipelago (ficus, pandanus, etc.). This indicates that many millions of years ago there were land connections between the continents. Since the climate of most of Australia is characterized by extreme aridity, its flora is dominated by dry-loving plants: special cereals, eucalyptus trees, umbrella acacias, succulent trees (bottle tree, etc.). Trees belonging to these communities have a powerful root system, which goes 10-20, and sometimes 30 m into the ground, thanks to which they, like a pump, suck out moisture from great depths. The narrow and dry leaves of these trees are painted mostly in a dull gray-greenish color. Some of them have leaves facing the sun with their edges, which helps reduce the evaporation of water from their surface. Tropical rainforests grow in the far north and northwest of the country, where it is hot and the warm northwest monsoons bring moisture. Their tree composition is dominated by giant eucalyptus, ficus, palm trees, pandanus with narrow long leaves, etc. The dense foliage of the trees forms an almost continuous cover that shades the ground. In some places on the coast itself there are thickets of bamboo. In places where the shores are flat and muddy, mangrove vegetation develops. Rain forests in the form of narrow galleries stretch for relatively short distances inland along river valleys. The further south you go, the drier the climate becomes and the more intense the hot breath of the deserts is felt. Forest cover is gradually thinning. Eucalyptus and umbrella acacias are located in groups. This is a zone of wet savannas, stretching in the latitudinal direction south of the zone tropical forests. In appearance, savannas with sparse groups of trees resemble parks. There is no shrubby growth in them. sunlight freely penetrates through a sieve of small tree leaves and falls onto the ground covered with tall, dense grass. The central desert parts of the continent, where it is very hot and dry, are characterized by dense, almost impenetrable thickets of thorny low-growing shrubs, consisting mainly of eucalyptus and acacia trees.

In Australia these thickets are called scrub. In some places, the scrub alternates with vast, devoid of vegetation, sandy, rocky or clayey desert areas, and in some places with thickets of tall turfy grasses (spinifex). The eastern and southeastern slopes of the Great Dividing Range, where precipitation is high, are covered with dense tropical and subtropical evergreen forests. Most of these forests, as elsewhere in Australia, are eucalyptus trees. Eucalyptus trees are valuable industrially. These trees are unrivaled in height among hardwood species; some of their species reach 150 m in height and 10 m in diameter. Wood growth in eucalyptus forests is high and therefore they are very productive. There are also many tree-like horsetails and ferns in the forests, reaching 10-20 m in height. At their top, tree ferns bear a crown of large (up to 2 m in length) feathery leaves. With their bright and fresh greenery, they somewhat enliven the faded bluish-green landscape of eucalyptus forests. Higher in the mountains there is a noticeable admixture of damarra pines and beech trees. The shrub and grass cover in these forests is varied and dense. In less humid variants of these forests, the second layer is formed by grass trees. On the island of Tasmania, in addition to eucalyptus trees, there are many evergreen beech trees related to South American species. In the southwest of the mainland, forests cover the western slopes of the Darling Range, facing the sea. These forests consist almost entirely of eucalyptus trees, reaching considerable heights. The number of endemic species here is especially high. In addition to eucalyptus trees, bottle trees are widespread. They have an original bottle-shaped trunk, thick at the base and sharply tapering at the top. During the rainy season, large reserves of moisture accumulate in the trunk of trees, which are consumed during the dry period. The undergrowth of these forests contains many shrubs and herbs, full of bright colors. In general, Australia's forest resources are small. The total area of ​​forests, including special plantations consisting mainly of softwood species (mainly radiata pine), amounted to only 5.6% of the country's territory at the end of the 1970s. The first colonists did not find plant species characteristic of Europe on the mainland. Subsequently, European and other species of trees, shrubs and grasses were introduced to Australia. The grapevine and cotton plant have taken root here well. Cereals include wheat, barley, oats, rice, corn and others. As well as vegetables, many fruit trees, etc. In Australia, in a natural sequence, all types of soils characteristic of the tropical, subequatorial and subtropical natural zones are represented.

Australian inland waters

The position of most of the continent in the zone of desert and semi-desert tropical climate determines the weak development of surface runoff, both external and internal. In terms of the total volume of annual runoff (350 / km2), Australia ranks last among other continents. Over almost its entire area, the runoff layer is about 50 mm per year. The runoff layer reaches its greatest values ​​(400 mm or more) on the windward wet slopes of the East Australian Mountains. 60% of the continent's area has no flow to the ocean and has only a sparse network of temporary watercourses (creeks). The densest network of calls is in the Central Basin, with much less on the Western Plateau. Water appears in them only after episodic rainfalls; they often end in drainless basins, which in the pluvial era of the Quaternary period were large freshwater lakes fed by the waters of large permanent rivers. Now these lakes are almost dry, their baths are occupied by salt marshes. Even Australia’s largest endorheic lake, Eyre, is covered with a crust of salt up to 1 m thick in the dry season, and in the rainy season (summer) it overflows over an area of ​​up to 1,500 km2. The beds of Australia’s longest creeks, Cooper Creek and Diamantina, end on the shores of the lake. Outlying areas of Australia have flow to Indian Ocean(33% of the runoff from the total area of ​​the continent) and to the Quiet. Rivers that flow into the ocean tend to be short and steep, especially those draining from the East Australian Mountains. The volume of flow, as well as the regime of river levels, is different and significantly depends on the amount of precipitation and the time of its occurrence. The deepest and most uniform in flow are the rivers starting in the East Australian Mountains (Burdekin, Fitzroy, Burnett, etc.). The rivers of the western coast (Fortescue, Gascoyne, etc.) flowing from the semi-desert coastal plateaus are the least deep and unstable. Surface drainage is completely absent on the Nullarbor karst plain adjacent to the Great Australian Bight. There are only two large rivers in Australia - the Murray and the Darling. Beginning in the Australian Alps, the Murray is the most abundant river in Australia (basin area 1072 thousand km2, length 1632 m). It is fed mainly by rain and to a lesser extent by snow. Flowing with a barely noticeable gradient across the vast southeastern plains of the Central Lowlands, the river loses a lot of water to evaporation and barely reaches the ocean. At its mouth it is blocked by sand spits. The main tributary of the Murray, the Darling River, is the longest river in Australia (basin area 590 thousand km2, length 2450 m), but it is even less deep, and during dry seasons its waters, lost in the sands, do not reach the Murray.

A distinctive feature of Australia is its wealth of groundwater. They accumulate in artesian basins occupying troughs of the ancient foundation along the edges of the Western Plateau and in the Central Lowland. Aquifers Mesozoic sediments serve mainly; dense Paleozoic rocks are waterproof. Groundwater recharge occurs mainly due to atmospheric precipitation. The groundwater in the central parts of the basins they occur at great depths (up to 20 m, in some places up to 1.5 km). When drilling wells, they often come to the surface under natural pressure. Australia's largest underground water basin is called the Great Artesian Basin. It covers almost the entire Central Lowlands from the Gulf of Carpentaria to the middle reaches of the Darling River. On the territory of the basin there is a large number of artesian wells that provide mineralized water, sometimes warm and even hot. In the semi-desert and desert regions of Australia, artesian basins are of great importance. But due to the mineralization of water, they are used not so much for irrigation as for the needs of industry and transport and, mainly, for creating reservoirs in pastoral areas (in southern Queensland, New South Wales and Victoria ).

Geographical zones of Australia

In Australia, just like in Africa, geographic zoning is clearly expressed, since the prevailing flat terrain does not disturb its manifestation. The position of the middle and widest part of the continent in the tropical zone determines the preferential development of geographical zones of this belt in Australia. Among them, the most common zone is tropical spinifex deserts, with rocky and clayey primitive soils and large tracts of sand, but, unlike Africa and South America, the deserts of Australia do not extend to the west coast. Due to slightly increased moisture there is a zone of shrubby semi-deserts. In the north, semi-deserts occupy a narrow strip and are quickly replaced in the subequatorial belt by zones of savannas, open forests and shrubs with red-brown and red soils. In the interior regions of the savannah, they bear arid features with the widespread development of the mulga-scrub formation) (in the subzone of deserted savannas). To the north, in a strip of moderately insufficient moisture, there is a subzone of typical savannas, with a dense grass cover and isolated trees. On the coast of the Arafura and Timor Seas, where, due to the very humid summer, moisture reaches optimal standards, a subzone of wet tall grass savannas and savanna forests appears. The former occupy areas of better drainage and greater soil dryness, while the latter are confined to depressions and depressions in the relief with a higher level of groundwater. In the south zone tropical deserts framed by a zone of subtropical semi-deserts, occupying the largest area in the inner continental sector. It is characterized by the mulga scrub scrub and open karst landscapes of the Nullarbor Plain. In the southwest and southeast, semi-deserts very quickly turn into shrub steppes on gray-brown soils with thickets of mallee scrub. In the extreme southwest steppe zone transitions into a zone of Mediterranean dry forests and shrubs with azonal relict yellow soils and red soils on lateritic crusts, characteristic only of Australia. In the southeast, as we approach the Eastern Highlands, moisture increases due to summer monsoon rains, as a result of which the steppes are replaced by a zone of peculiar eucalyptus savannas with dense grass cover and eucalyptus woodlands along river valleys. The East Australian Mountains are the only significant zonal orographic barrier in Australia. Along the windward eastern slopes of the mountains stretch, as noted, forest areas, the landscape differences of which depend on the position in the subequatorial, tropical or subtropical zones.

In the subequatorial belt (north of 19° S) there is a zone of permanently humid forests, which is characterized by high summer temperatures and significant annual precipitation, floristic richness and the presence of lateritic podzolized soils in the coastal zone. Between 19° and 30° S. w. There is a zone of trade wind tropical forests on red soils and yellow soils. Finally, the southeastern slopes of the East Australian Mountains lie in the zone of moist subtropical forests, under which mountain-forest brown soils have formed. On the western leeward slopes, forest zones are clearly visible only in the northern part, where the mountains reach their greatest width. Usually wet subequatorial forests move into the zone of mixed (deciduous-evergreen) forests, represented in Australian conditions by eucalyptus woodlands.

Source - Geographical Encyclopedia

Since ancient times, people have flocked to Australia in search of gold and for the rich pastures where they raised huge numbers of livestock. Modern research has shown that the continent has a huge amount of reserves of different types of minerals.

Australia now ranks first in the world in the production of iron ores, bauxite, lead and zinc, 2nd in uranium mining (after Canada), and 6th in coal mining.

Relief features of Australia

In ancient times Australia was integral part Gondwana is one of the two largest continents. Australia broke away around the end of the Mesozoic era, and now most of the continent rests on an ancient platform. Therefore, the relief of Australia is dominated by plains, where the richest deposits of sedimentary rocks are located. About 95% of the country's territory does not rise above 600 m above sea level.

A narrow strip of plateau stretches along the western coast. These are the Western Australian Plateau (average heights - 200 m) and the MacDonnell Range (with the highest peak of Zyl - 1511 m). There are deposits of oil, gas, iron ore, bauxite, titanium, and gold here.

The center of the continent is dominated by lowlands. The lowest point in Australia is recorded in the Lakes Eyre region - minus 16 m from sea level. Copper, manganese, and opals are mined in this area.

In the east of the continent there is the Great Dividing Range - these are high mountains with steep slopes, mainly of volcanic origin, made of limestone, granite and volcanic rocks. This mountain system stores considerable reserves of hard and brown coal, rich deposits of oil and gas, tin, gold, and copper. The highest peak of the continent is located here - Mount Kosciuszko (2228 m). The largest Australian rivers, the Murray and Darling, originate on the slopes of the Great Dividing Range.

Types of minerals

Iron ore- a mineral formation containing large amounts of iron. In terms of iron ore production, Australia, together with Brazil and China, provides 2/3 of world production. The largest deposits have been discovered in the north-west of the mainland - these are the Mount Newman and Mount Goldsworth basins. Ore is also mined in South Australia (the largest deposit is Iron Knob). The Australian company BHP Billiton is one of the world's three largest concerns for the production of iron ore raw materials. This concern alone provides the world with about 188 million tons of ore. Currently, Australia is also the world's largest exporter of ore. Each year, more than 30% of world exports come from this country.

Bauxite- complex rock, from which aluminum is extracted. Australia ranks second in the world in terms of bauxite deposits, second only to Guinea. According to experts, more than 7 billion tons of valuable ore are stored on the southern continent, which amounts to almost 26% of the world reserve. In Australia, bauxite is found in mountainous areas. The largest deposits: Weipa (Cape York), Gov (Arnhem Land), Jarrahdale (on the slopes of the Darling Range).

Polymetals- complex ore containing a whole set of chemical elements, of which the most important are zinc, lead, copper, silver and gold. Large deposits of polymetallic ores have been discovered in New South Wales (Broken Hill deposit), in Queensland (Mount Is deposit) and in the north of Australia (Tennant Creek deposit).

Gold- a valuable metal that has found application not only in jewelry, but also in electronics, the nuclear industry, and medicine. Australia ranks 4th in the world in gold production. More than 225 tons are mined here every year. The main gold deposits are concentrated in the southwest of the mainland - in the state of Western Australia. The largest mines are located near the cities of Kalgoorlie, Wiloon and in Queensland.

Coal- the most important type of fuel of organic origin. According to experts, almost 9% of the world's coal reserves are concentrated in Australia - that's more than 76.4 billion tons. The main coal basins are located in eastern Australia. The largest deposits are in the states of New South Wales and Queensland.

Oil and natural gas - valuable fuel resources, of which Australia does not have many (compared to other countries, and even more so continents). The main deposits of oil and gas were discovered on the shelf near the coast. The largest oil fields are: Mooney, Alton, Bennett (Queensland), Kingfish (Victoria) and on Barrow Island. The largest gas field is Ranken.

Chromium- a metal used in heavy industry. Rich deposits of chromium have been discovered in Australia. Large deposits: Gingin, Dongarra (Western Australia), Marlin (Victoria).

By production diamonds and opals Australia ranks first in the world. The largest diamond deposit is located in the area of ​​Lake Argyle. And most of the opals (2/3) are found in South Australia. The unusual underground city of Coober Pedy is also located here, which is often called the opal capital of the world. Most of the housing in the city is located in underground mines.

Resources and deposits

Mineral resources. Australia is one of the world's five largest suppliers of mineral raw materials. The mining industry provides a third of the country's total industrial output. Australia's mineral raw materials are exported to more than 100 countries.

Water and forest resources Australia is small. In terms of water supplies, it is the poorest continent on earth. There are few rivers, and 90% of rivers dry up during the dry season. Only the Murray and its tributary, the Murrumbidgee, maintain a constant flow throughout the year. The main forest areas are located in the east and west of the continent. Thickets of eucalyptus trees are especially valued.

Land resources Australia is vast, but almost 44% of the continent is desert. However, semi-deserts and steppes are used for extensive pastures. Sheep breeding is very developed, which is often called the “business card” of the Australian economy. The country occupies a leading position in the world in the production of meat and butter.

Fertile soils are located in steppe regions. They grow mainly wheat. Rich harvests of sugar cane, tobacco, and cotton are also harvested. IN Lately Winemaking and viticulture are increasingly developing.