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Friday 1 April 2011

Introduction-Himalayan Mountains









The colossal Himalayan Mountains form a border between the Indian subcontinent and the rest of Asia. The Himalayas are the world’s tallest mountains, towering more than five miles above sea level. Himalaya means “home of snow” 









because the tallest peaks of the Himalayas are always capped with snow. 






The Himalayas include Mount Everest, the tallest mountain in the world. Everest rises 29,028 feet above sea level on the border between India and Nepal. No plant life grows near the mountain’s peak due to powerful winds, extremely cold temperatures, and a lack of oxygen. Many adventurous people attempt to climb Everest every year. Often their venture ends in sickness or death. Most people are unable to breathe 20,000 feet above sea level because there is not enough oxygen in the atmosphere. A person will suffer brain damage when they are unable to breathe. Strong winds and frigid temperatures make the climate even more rigorous. Clearly the peak of Mount Everest is a place for only the heartiest of people. 



Formation

The Formation of the Himalayas
The Himalayas are known to be young fold mountains. Young, because these have been formed relatively recently in the earth's history, compared to older mountain ranges like the Aravallis in India, and the Appalachian in the USA. They are known as Fold Mountains because the mountains extend for 2500 km in length in a series of parallel ridges or folds.
The accepted theory about the formation of the Himalayas started to take shape in the year 1912 when German meteorologist Alfred Wegener developed his Theory of Continental Drift. According to Wegener, the earth was composed of several giant plates called tectonic plates. On these plates lie the continents and the oceans of the earth. The continents were said to have formed a single mass at one point in time. From this single mass, today's continents have "drifted" apart from each other over a period of millions of years.


We pick up the story about 250 million years ago. During this time, all the earth's land was a single super continent called Pangea, which was surrounded by a large ocean.
The continents, 180 Million years ago.
Around 200 million years ago (also known as the Middle Permian Period) , an extensive sea stretched along the latitudinal area presently occupied by the Himalayas. This sea was named the Tethys. Around this period, the super continent Pangea began to gradually split into different land masses and move apart in different directions.
As a result, rivers from both the northern Eurasian land mass (called Angara) and the southern Indian land mass (called Gondwana) started depositing large amounts of sediments into the shallow sea that was the Tethys. There were marine animals called ammonites living in the sea at the time. The two land masses, the Eurasian and the Indian sub-continent, moved closer and closer. Indian plate was moving north about at the rate of about 15 cm per year (6 inches per year).
The initial mountain building process started about seventy million years ago (or the Upper Cretaceous period) when the two land masses (or plates) began to collide with each other. As a result, the already shallow seabed rapidly folded folded and was raised into longitudinal ridges and valleys. 

Collision

The collision between the Indian subcontinent and Eurasian continent, which started in Paleogene time and continues today, produced the Himalayas and Tibetan Plateau, spectacular modern examples of the effects of plate tectonics. Tibetan Plateau itself is a collage of micro plates or continental fragments that were successively added to the Eurasian plate during the Paleozoic and Mesozoic eras. Paleomagnetic analysis indicates that these older micro plates were in the southern hemisphere during the Paleozoic era. Each older fragment, like the larger Indian Plate, made a long northward journey as the intervening ocean was subducted, and was accreted to the Eurasian continent. The resulting sutures are marked by scattered occurrences of ophiolite, ocean floor material that was caught up between the crustal blocks during accretion. The collision that produced the Himalayas was only the latest, albeit climactic, episode in this long series of collisions.

People living near Himalaya

They are very dependent on the yak.
They use it for transportation and food like butter and meat. They mainly work as tour guides, which works well as many ppl visit the Himalayas. They also build small stone houses at the base of the mountain.

Natural Vegetation

Approximation 1900 plants growing. Many are used for medicinal purposes and can only be found in the Himalayas. AS the climate can be harsh in the Himalayas, plants are usually found fairly close to the land and has a short growing season. Some examples of natural vegetation: pine and fir trees, bamboo plants(found at the lowest part of Himalayas and typically grows in a forest environment). At a slightly higher land, alpine scrubs and other shrubs and bushes are found. At an even higher ground alpine scrubs can still be found, but more limited plants and vegetation like lichen and moss are contained at higher zones of the Himalayas.