Himalayas,Giants Sky

The Himalayas

The Himalayas, is a mountain range in Asia separating the plains of the Indian subcontinent from the Tibetan Plateau.

The Himalayan range is home to the planet's highest peaks, including the highest, Mount Everest. The Himalayas include over a hundred mountains exceeding 7,200 metres (23,600 ft) in height. By contrast, the highest peak outside Asia—Aconcagua, in the Andes— is 6,961 metres (22,838 ft) tall.The Himalayas have profoundly shaped the cultures of South Asia. Many Himalayan peaks are sacred in both Buddhism and Hinduism.

Besides the Greater Himalayas of these high peaks there are parallel lower ranges. The first foothills, reaching about a thousand meters along the northern edge of the plains, are called the Sivalik Hills or Sub-Himalayan Range. Further north is a higher range reaching two to three thousand meters known as the Lower Himalayan or Mahabharat Range.

The Himalayas abut or cross five countries: Bhutan, India, Nepal, China, and Pakistan, with the first three countries having sovereignty over most of the range. The Himalayas are bordered on the northwest by the Karakoram and Hindu Kush ranges, on the north by the Tibetan Plateau, and on the south by the Indo-Gangetic Plain.

Three of the world's major rivers, the Indus, the Ganges, and the Tsangpo-Brahmaputra all rise near Mount Kailash to cross and encircle the Himalayas. Their combined drainage basin is home to some 600 million people.

Lifted by the collision of the Indian tectonic plate with the Eurasian Plate,[4] the Himalayan range runs, west-northwest to east-southeast, in an arc 2,400 kilometres (1,500 mi) long. Its western anchor, Nanga Parbat, lies just south of the northernmost bend of Indus river, its eastern anchor, Namcha Barwa, just west of the great bend of the Tsangpo river. The range varies in width from 400 kilometres (250 mi) in the west to 150 kilometres (93 mi) in the east.

Himalayas

Himalayas range

Geography: The Himalayas stretch across the northeastern portion of India. They cover approximately 1,500 mi (2,400 km) and pass through the nations of India, Pakistan, Afghanistan, China, Bhutan and Nepal. The Himalayan range is made up of three parallel ranges often referred to as the Greater Himalayas, the Lesser Himalayas, and the Outer Himalayas. 

Ecology: While intimidating mountains like Everest and 2K tend to dominate our perceptions of the region, the Himalayas are rich in biodiversity. Climates range from tropical at the base of the mountains to perennial snow and ice at the highest elevations. These complex and diverse eco-regions are interconnected: an ecological threat to one is ultimately a threat to many. Here are just a few examples of Himalayan ecology:

Montane Grasslands and Shrublands:

 Western alpine shrubs and meadows can be found between 9,850 and 16,400 ft. These areas tend to have cold winters and mild summers that allow for plant growth. Rhododendron plants cover the lower shrublands, while the alpine meadows, directly above, host a range of flora in the warmer months. Animals found in this region include the snow leopard, Himalayan tahr, musk deer, and pikas.

  

Montane Grasslands

Temperate Coniferous Forest:

 In the northeast, temperate sub-alpine conifer forests are found at elevations of 8,200 to 13,800 ft. Located in the inner valley area, these forests are protected from harsh monsoon conditions by surrounding mountain ranges. The dominant tree types are pine, hemlock, spruce, and fir. Animals found in this region include red pandas, takins, and musk deer.

  

Temperate Coniferous Forest

Temperate Broadleaf and Mixed Forests:

 Found in middle elevations of 6,600 to 9,800 ft. in the eastern region are broadleaf and coniferous forests. These forests receive almost 80 inches of annual rainfall, mostly during the monsoon season. In addition to indigenous oaks and maples, plants like orchids, lichen, and ferns also grow in the area. A huge range of wildlife, including over 500 species of birds, are found here during the cooler seasons before they migrate to higher elevations to escape the hot summers. This is also the primary home for golden langur monkeys.

  

Tropical and Sub-tropical Broadleaf Forests:

 Located at 1,650 to 3,300 ft. along a narrow strip of the outer Himalayan range are the Himalayan sub-tropical broadleaf forests. Here there is a wide range of plant life thanks to the areas varied topography, soil types, and rainfall levels. Forest types include subtropical dry evergreen, northern dry mixed deciduous forests, moist mixed deciduous forests, subtropical broadleaf forests, northern tropical semi-evergreen forests, and northern tropical wet evergreen forests. Wildlife includes many threatened species including tigers and Asian elephants. More than 340 different species of birds can be found in this region.

Tropical and Sub-tropical Broadleaf Forests:

Rivers: The Himalayas are the source for the Indus, the Yangtze and the Ganga-Brahmaputra. All three are major river systems for the continent of Asia. 

The main rivers sourced in Himalayas are the Ganges, Indus, Yarlung, Yangtze, Yellow, Mekong, and Nujiang.

Gange river

Glaciers: The Himalayas are the third largest deposit of ice and snow in the world, after Antarctica and the Arctic. There are approximately 15,000 glaciers located throughout the range. At 48 miles (72 km) in length, the Himalayan Siachen glacier is the largest glacier outside the poles.

Glaciers of Himalaya

Geology

Mechanics of Mountain Formation

 To understand the fascinating mechanics of the collision of India with Asia we must first look beneath the Earth's surface. The continents are carried by the Earth's tectonic plates like people on an escalator. There are currently 7 giant plates sliding across the Earth's surface, and a handful of smaller ones. There may have been more or fewer plates in the past. Currently they slide, collide, and recede from one another at rates of 1-20 cm/year. They are driven by internal heat deep in the earth that is able to escape efficiently only by convection. Convection is the process that drives hot currents of gas or liquid upwards because they are less dense, and cold currents of liquid downwards because they are more dense.

Continental Plates

In some ways, the continents are like giant accumulations of rock debris lying atop the tectonic plates. Continents are the "scum of the Earth," consisting mostly of light minerals like quartz, which can't sink into the Earth's dense mantle. 

 For at least 80 million years the oceanic Indian Plate continued its inexorable collision with southern Asia, including Tibet. The heavy ocean floor north of India acted like a giant anchor, plunging rapidly into the mantle, and dragging the Indian continent along with it, northward, towards Tibet. 

 As the plates collided, the sinking ocean floor generated volcanoes in southern Tibet because the rock at the top of the descending plate melted, from friction and the huge pressures of collision. However, by 25 million years ago the fast moving Indian continent had almost entirely closed over the intervening ocean, squeezing the sediments on the ocean foor. Since the sediments were lightweight, instead of sinking along with the plate, they crumpled into mountain ranges—the Himalayas.

 By 10 million years ago the two continents were in direct collision and the Indian continent, because of its enormous quantity of light quartz-rich rocks, was unable to descend along with the rest of the Indian plate. It was at about this time that the anchor chain must have broken; the descending Indian plate may have fallen off and foundered deep into the mantle.

 Although we don't fully understand the mechanism of what happened next, it's clear that the Indian continent began to be driven horizontally beneath Tibet like a giant wedge, forcing Tibet upwards. Tibet, meanwhile, is behaving like a giant roadblock that prevents the Himalaya from moving northward. Under the peaks and under most of Tibet the Indian plate is apparently gliding along almost frictionlessly.

Mount Everest.

The elevation of Mount Everest was first observed in 1849, but its height was not computed till 1852. Though half a century has elapsed since its discovery and the mountains of Asia have been continually explored in the interval, no second peak of 29000 feet has been found. There is but little probability now of a higher peak than Mount Everest being discovered and even the prospect of finding new peaks of 27000 or 26000 feet is becoming remote.

Mount Everest.

Some geographers have held that peaks higher than Mount Everest were standing behind it to the north, but their opinion was not founded on trustworthy observations, and when Major Ryder traversed Tibet along the Brahmaputra in 1904 he passed 80 miles north of Mount Everest and found no peak approaching it in height.

Three panoramas showing the outline of Mount Everest are included in chart vi. Owing to the objections of the Nepalese Government Mount Everest cannot be approached by surveyors from the side of India within 80 miles, and the trigonometrical observations that have been made of the Everest-Makalu group of peaks have been carried out under great disadvantages. The following description of Mount Everest is taken from a report by Colonel Tanner :

"The outline of Everest is rather tame than otherwise; it is fairly sharp and has a long snowy "slope on its north-east flank, the south-east being precipitous. Peaks of 22000 feet and thereabouts "encircle its southern base, and below them are seen many outlines of dark mountain masses which "are without snow.

"From due south, near the Kosi river in the Bhagalpur district, Everest is by no means a marked "feature in the landscape; its southern face has but 190 feet of snow, below which the mountain «' falls for 4000 to 5000 feet in a series of crags of very dark-coloured rock, only here and there dashed "and streaked with snow, below which are snow fields and broken masses of rock intermingled "with snow and neve. When the atmosphere is not very transparent the sharp tip is seen as a "mere floating white speck, the rock below it being almost exactly of the colour of the sky and there"fore invisible.

"The southern face of Everest from a near point of view is doubtless wild, and its cliffs must "be very lofty, but the great distance from which it is viewed renders this aspect of the mountain "uninteresting. In fact, from the south, Everest has all the appearance of a very moderate hill, not "in the least imposing and hardly picturesque. It is interesting only because by trigonometrical "operations its summit has been found to rise up further from the general level of the earth's "surface than that of any other point."

Future of the Himalaya

 Over periods of 5-10 million years, the plates will continue to move at the same rate, which allows us to forecast fairly reliably how the Himalaya will develop. In 10 million years India will plow into Tibet a further 180km. This is about the width of Nepal. Because Nepal's boundaries are marks on the Himalayan peaks and on the plains of India whose convergence we are measuring, Nepal will technically cease to exist. But the mountain range we know as the Himalaya will not go away. 

 This is because the Himalaya will probably look much the same in profile then as it does now. There will be tall mountains in the north, smaller ones in the south, and the north/south width of the Himalaya will be the same. What will happen is that the Himalaya will have advanced across the Indian plate and the Tibetan plateau will have grown by accretion. One of the few clues about the rate of collision between India and Tibet before the GPS measurements were made was the rate of advance of Himalayan sediments across the Ganges plain. There is an orderly progression of sediments in front of the foothills. Larger boulders appear first, followed by pebbles, and further south, sand-grains, silts, and finally very fine muds. This is what you see when you drive from the last hills of the Himalaya southward 100 km. The present is obvious, but the historical record cannot be seen on the surface because the sediments bury all former traces of earlier sediments. However, in drill holes in the Ganges plain, the coarser rocks are always on the top and the finer pebbles and muds are on the bottom, showing that the Himalaya are relentlessly advancing on Indi

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