Tag Archives: Geography

When and how were the Himalayas formed?

The Himalayas or Himalaya is the tallest mountain range in the world. Literally meaning the ‘abode of snow’ in Sanskrit, this natural wonder has the third largest deposit of snow and ice, after the poles. The Himalayas extend for some 2400 km, spanning Pakistan, India, Nepal, China and Bhutan. It is home for nine of the ten tallest peaks in the world, including Mount Everest, the tallest peak in the world which measures 8848 m. The mountain range is also the source of some major rivers in the world, such as Indus, Ganges and Bhramaputra. Himalaya serves as a natural border of India, and has played a big role in sketching the culture and lifestyle of the subcontinent. Himalaya has great significance in Hinduism and Buddhism.
Despite its amazing superlatives, the Himalaya is comparatively a younger mountain range. In fact, it is one of the youngest, with an age estimated to be around only 50 million years. A lot of research had gone into understanding the formation of Himalayas. It is believed to have been formed as a result of a collision between two tectonic plates, Indo-Australian and Eurasian.
According to German scientist Alfred Wagner’s Theory of Continental Drift, there had been only a single large continent named Pangaea. The landmass then began to break up and move towards and from each other. About 200 million years ago, India was an island floating off the coast of Australia. It was separated from Asia by the Tethys ocean. As Pangaea began to break, the Indian plate began to drift towards Asia in North. It traveled more than 6000 km in a period of 150 million years before finally colliding with the Eurasian plate. The Tethys ocean went out of existence, having been closed by the Indian plate.
When collided, neither of the plates could be subducted because their crusts were of low density. Instead they were folded and faulted along the threshold, forming the Himalayan mountain range. The mountain grew over millions of years, assuming the current form.
The Indian plate is still drifting towards North, with a speed of 67 millimeters per year. As a result, the height of Himalaya is also increasing, with a rate of 5 millimeters per year, though impeded by erosion and gravity. The movement of Indian plate makes the area susceptible to seismic activities. Recurring earthquakes are evidence of the movement, and it will continue to rise in future years. Hence, the area is becoming more dangerous for living. Add to that unscientific construction practices, a catastrophe is waiting to happen.

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What is the difference between the UK, England, and Great Britain?

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People often use the names the UK, Great Britain and England for each other, much to the ire of the natives. Sometimes the name England is used to refer to whole of the UK or the Great Britain. This can be offending to the people of Wales and Scotland since there is significant geographical and cultural difference among the three regions.
The major difference among the UK, the Great Britain and England is that the first one is a sovereign state, the second one is an island and the last one is a part of an island.
The United Kingdom is an independent country, its capital is London. The official name of the country is The United Kingdom of Great Britain and Northern Ireland. It consists of the island of Great Britain and the north portion of the island of Ireland. The rest of the island of Ireland is another independent country.
The Great Britain, also called Britain, is the name for the island that constitutes a major part of the United Kingdom. With and area of 209,331 sq km, it lies northwest to France and east to Ireland. The Great Britain is called so because it is the largest island of the British Isles, which also include the island of Ireland, the Isle of Man, the Isles of Scilly, The Channel Islands and 6,000 other smaller islands.
The Great Britain is composed of three autonomous regions; Wales, Scotland and England. Wales occupies the southwest portion of the island, while England is in the southeast, and Scotland is in the north. England is the largest of the three regions in terms of area and population. These regions differ in their culture and lifestyle, and have some autonomy regarding to their internal governance.
These lands were all independent long ago. The Kingdom of England had been established by the Anglo-Saxons before 10th century. In 1536, King Henry VIII enacted a bill that united Wales with the Kingdom of England. In 1603, the Scottish king James VI inherited the English throne from Elizabeth I. In 1707, the Act of union was passed by the Scottish and English parliaments to form the Kingdom of Great Britain. In 1801, the Irish parliament also decided to join the kingdom, forming the United Kingdom of Great Britain and Ireland. However, the southern colonies of Ireland withdrew from the union and declared independence in 1922, forming the Iris Free State. The kingdom underwent another name change, becoming United Kingdom of Great Britain and Northern Ireland. This is the United Kingdom that remains today.

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Which countries are geographically spread over two continents?

By official count, there are eight countries that straddle two continents.
More than two-thirds of Russia lies in Asia, though about 75% of population lives in the smaller European part. Most of Turkey lies in Europe, but a tiny piece (about 3%) lies in Asia across the Bosporus Strait. While most of Egypt is in Africa, the Sinai Peninsula is physically a part of Asia. Socotra Island, which lies off the Horn of Africa, is part of the West Asian republic of Yemen. Spanish cities of Ceuta and Melilla are physically parts of Africa. Similarly, Portugal’s Madeira Island group is physically part of Africa rather than Europe. Indonesia consists of 13,700 islands. The eastern islands (including Papua, formerly known as Irian Jaya) are counted as part of Oceania rather than Asia. The US also lies on two continents – the state of Hawaii is part of Oceania.

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Which is the wettest place in the world? Cherrapunji, Mawsynram, or Waialeale?

For almost 150 years Cherrapunji was considered to be the city that received the highest rainfall in the world, but later on when the officials of meteorological department of India arranged a rain-gauge at the place called Mawsynram which is just 9 kilometers away from Cherrapunji (see map below) they put the record of Cherrapunji at stake. The rain-gauge at Mawsynram measured more rainfall. Also, the American tourist department is publicizing a place named Mt. Waialeale on the Hawaii Islands as the world’s wettest place in order to attract tourists.
In recent years there have been many monsoons when the status of Cherrapunji has been viewed askance. For example, in 2008 Mawsynram received 14,985 millimeters of rainfall. The second highest rainfall was noted in Waialeale at 11,684 millimeters and third place of Cherrapunji which received 11,415 millimeters of rainfall.
Cherrapunji is situated at a crucial location at an altitude of 1,313 meters (4,307 feet) in the Khasi mountain range of Meghalaya state of India. The south-westerly and north-easterly winds meet here. As a result, Cherrapunji gets the benefit of two rainy seasons. This is known as ‘relief precipitation’ in meteorological jargon. This phenomenon is the sole reason for the heavy rainfall which Cherrapunji receives. The humid air travels through the jungles on the Khasi hills, clashes against the mountain range, and moves in an upward direction. When this moisture encounters the cold air at the height it condenses to form raindrops and the clouds full of water rain down on Cherrapunji.
The devaluation of Cherrapunji as the world’s wettest place is not quite correct. The amount of rainfall depends on where the rain-gauge has been placed. Just as the meteorological department arranged the rain-gauge at Mawsynram, a place just 9 kilometers away from Cherrapunji, they could have placed another gauge at some other site in Cherrapunji itself and this could have measured rain more than that at Mawsynram.
The case of mountain known as Mt. Waialeale is not very strong either. There is no specific monsoon here. There is continuous rainfall for about 335 to 350 days in a year — and that too in the limited area of about 5 square kilometers. (Mt. Waialeale is on Kauai island in the sea and there is no human habitation there.) The rainfall of Cherrapunji covers an area of about 100 to 200 square kilometers.
In spite of this the circumstances are such that Cherrapunji might lose its Numero Uno status with the passage of time. For the past few years now the average rainfall received by this place has has gone down to some extent because the forests on the Khasi hill slopes have continuously been felled for wood for fuel and to make space for agriculture. Once the vegetation is destroyed the crags and soil of the mountains that have been rendered uncovered absorb the moisture present in the air and themselves becomes moist. Consequently, clouds do not form. To change this situation the environment department of Meghalaya state has started planting trees on the slopes of the Khasi hills on a large scale. It remains to be seen if 150 year long record of Cherrapunji as the place that receives the highest rainfall remains intact.

Additional reading:
Cherrapunji (Wikipedia)
Mount Waialeale (Wikipedia)

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Is Mount Mauna Kea of USA taller than the Mount Everest?

The answer is an equivocal ‘yes’ and ‘no’! In the ultimate analysis the answer depends upon the base line from which the height is measured. Having altitude of 8,848 meters (29,028 feet) above the sea level, Mount Everest is located on the terra firma (land) of the Asian continent; while the base of the Mount Mauna Kea of Hawaii Island is on the floor of the Pacific Ocean. If measured from the base at the bottom of the Ocean up to its peak, the overall height of the Mount Mauna Kea adds up to 10,205 meters (33,480 feet) — making it 1,357 meters taller than the Mount Everest! 
Mount Mauna Kea of Hawaii Island
However, since a significant mass of Mt. Mauna Kea (photo, above) — nearly 6,000 meters — is situated under the sea level, its summit is much lower than that of Mt. Everest.

Additional reading:
Mauna Kea (Wikipedia)
Mount Everest (Wikipedia)

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Which is the remotest inhabited island? How far is it from the nearest human habitation?

There is a small 110-square kilometer island named Tristan-da-Cunha situated in the huge 8,22,17,000-square kilometer Atlantic Ocean between the continents of South America and Africa which enjoys unenviable honor of being the most isolated human habitation on Earth. The nearest human habitation from this island named after its discoverer, the Portuguese Admiral Tristao-da-Cunha in 1506, also happens to be another small island named St. Helena which is 2,110 kilometers distant. (Refer to the map.)
Having an area of 120 square kilometers and population of about 7,000 the St. Helena Island is famous as the home of Napoleon Bonaparte during his exile after the Battle of Waterloo. Coming back to Tristan-da-Cunha Island. It was gradually raised from the bottom of the Atlantic Ocean by the successive layers of the cooling lava erupting due to the volcanic activity. Continuing volcanic activity has raised the volcano’s crater to the altitude of 2,060 meters (6,760 feet) above the sea level. Many years later, possession of this uninhabited island passed in the hands of Great Britain which established a navel base on the island in 1816 but wound it up next year while Napoleon was living on ‘neighboring’ St. Helena Island. However, three of the colonists decided to remain behind amidst pristine sylvan environment of the island. With the passage of time inhabitants increased as the lucky shipwrecks managed to reach the shore of Tristan-da-Cunha Island. The island continued to be a British possession and by 1886 the population grew to 97 souls. The volcanic activity resumed in the 20th century and when the volcano erupted on October 9, 1961, all the inhabitants were evacuated immediately and brought to Britain. Not all the evacuees felt at home in the hustle and bustle if Britain and many (198 to be precise) returned to their small, remote island home in 1963. Today the islanders who number 370 maintain only tenuous links with the outside world. (October 2011)

Additional reading:
Tristan da Cunha (Wikipedia)

How did South Africa come to be so well endowed with minerals?

More than four billion years ago the Earth’s crust was molten. When began to cool, continental nuclei, the cores around which continents later grew formed. As it happened, south central Canada, Brazil, part of Russia, Australia, and South Africa all contain continental nuclei. That is, they possess the world’s oldest, or Archaean, rock, which is just the sort of rock that contains gold, iron, and manganese. But age isn’t enough. For rocks to yield their minerals readily, they must also be exposed. In this, too, South Africa was fortunate. While Brazil’s Archaean rock came to be covered by the Amazonian rain forests, Canada’s by glacial debris, Russia’s with steppes, and Australia’s with the thick soils of the outback, South Africa’s remained relatively unchanged by younger geological events. Even weathering has helped. The ancient rocks have eroded in such a way that some of their minerals, particularly gold; have been reconcentrated in sediments near the surface.

This explains South Africa’s wealth of easily accessible gold, iron, and manganese, but what of its other treasures-platinum, chromium and diamonds? These are the consequence of another bit of luck: The tip of Africa happens to be a ‘geological crossroads,’ where continents have built up and broken apart over time. When continental nuclei rupture, molten rock rises through the rifts, resulting in igneous rocks that fill the cracks. There are many such extrusions of igneous rock in the world, but the effects of rifting have been especially dramatic in South Africa. About 1.8 billion years ago South Africa’s Bushveld Complex, the biggest single igneous rock body on the face of the Earth (roughly the size of Ireland), was formed, leaving behind huge deposits of chromium and platinum.

Rifting also led to the formation of diamond fields 100 million years ago. The molten rock that rose from rift inter sections in South Africa contained pipes of kimberlite, which carry fully formed diamonds from great depths. Again South Africa isn’t unique in this regard. Arkansas, Wyoming, and Western Australia have had rifting, and have diamonds very similar to the ones in South Africa. But their kimberlite pipes aren’t as large or well formed, and therefore can’t carry as many big, high-quality diamonds up to the surface. Once more, South Africa was just plain lucky. Its kimberlite pipes are deep and protrude prominently through the brittle, ancient crust. Geological fate has indeed been very kind to South Africa. The rock there is readily available to be mined.

More reading:
Mining industry of South Africa (Wikipedia)

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Why does a river curve and twist instead of running straight?

The course of a river-bed entirely depends on the lie of the land. If this changes in course of time, the course of the river will change. The water runs downwards to the sea, pulled by the Earth’s attraction as near as it can get to the center of the Earth. It must run just as a ball would run on an irregular surface. Thus, sometimes, where the Earth falls evenly, like a tilted table, a river will run quite straight, but if there is a little hillock in the way the river will run round it.

When we notice the ordinary curves and twists in the course of a river, we may see no good reason for them, for all the land may look equally flat. But that is only because we can not, with out unaided eyes, see accurately enough. If we use a special instrument to show us how the land lies at any point, we shall find that the river is really doing the only thing it can – running downwards all the time.

More reading:
River (Wikipedia)

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Which is the driest place on the Earth? Atacama Desert?

The record of being the driest place on our planet clearly belongs to the 1,40,000 square kilometer Atacama desert in Chili, South America (see the map). It hasn’t experienced rainfall since last 450 years or so and it seems that the dry spell may have begun much earlier.

Atacama is the oldest desert. It was formed about 10 million years ago. Some of its areas are so hot and arid that even the hardiest bacteria are unable to survive in the hostile environment.

Additional reading:
Atacama Desert (Wikipedia)

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What is the number of active volcanoes in the world?

Including those which are submarine (under the surface of the sea), there are 1,343 active volcanoes. Indonesia, which comprises over 13,600 islands, has 76 historically active volcanoes. About 80% of them erupted in the 20th century. There have been 1,171 eruptions in recorded history of Indonesia. Japan, however, has witnessed 1,274 eruptions.

More Reading:
Volcano (Wikipedia)

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