» About Himalaya

Himalayas, the highest mountain range in the world, extend along the northern frontiers of Pakistan, India, Nepal, Bhutan, and Burma. They were formed geologically as a result of the collision of the Indian subcontinent with Asia. This process of plate tectonics is ongoing, and the gradual northward drift of the Indian subcontinent still causes earthquakes (see Earthquakes, this ch.). Lesser ranges jut southward from the main body of the Himalayas at both the eastern and western ends.

The Himalayan system about 2,400 kilometers in length and varying in width from 240 to 330 kilometers, is made up of three parallel ranges the Greater Himalayas, the Lesser Himalayas, and the Outer or Southern Himalayas sometimes collectively called the Great Himalayan Range.

Greater Himalayas
The Greater Himalayas, or northern range, average approximately 6,000 meters in height and contain the three highest mountains on earth: Mount Everest (8,796 meters) on the China-Nepal border, K2 (8,611 meters, also known as Mount Godwin-Austen, and in China as Qogir Feng) in an area claimed by India, Pakistan, and China; and Kanchenjunga (8,598 meters) on the India-Nepal border.

Southern Himalayas
Southern Himalayas, averaging 900 to 1,200 meters in elevation, lie between the Lesser Himalayas and the Indo-Gangetic Plain. In Himachal Pradesh and Uttar Pradesh, this southernmost range is often referred to as the Siwalik Hills. It is possible to identify a fourth, and northernmost range, known as the Trans-Himalaya.

Lesser Himalayas
The Lesser Himalayas, located in northwestern India in the states of Himachal Pradesh and Uttar Pradesh, in north-central India in the state of Sikkim, and in northeastern India in the state of Arunachal Pradesh, range from 1,500 to 5,000 meters in height. Located in the Lesser Himalayas are the hill stations of Shimla (Simla) and Darjiling (Darjeeling).

The southern slopes of each of the Himalayan ranges are too steep to accumulate snow or support much tree life, the northern slopes generally are forested below the snow line. Between the ranges are extensive high plateaus, deep gorges, and fertile valleys, such as the vales of Kashmir and Kulu.

The Himalayas serve a very important purpose. They provide a physical screen within which the monsoon system operates and are the source of the great river systems that water the alluvial plains below (see Climate, this ch.). As a result of erosion, the rivers coming from the mountains carry vast quantities of silt that enrich the plains.