The Himalayas

(Header Image: Image of Himalayas from Space from Google Earth (SK telecom, Google, Data SIO, NOAA, U.S Navy, NGA, GEBCO, Landsat/Copernicus))

The view of Asia from space is dominated by the presence of the Himalaya; A collosal mountain range, host to some of the world’s largest mountains.

These started to form 40-50 million years ago, as the northwards movement of the Indian plate and closure of the Tethys Sea caused the Indian landmass to collide with the Asian plate. The Indian plate, likely in part due to the large flood basalts from the end Cretaceous, (which played a part in the mass extinction event which ended the dinosaurs), was denser than the Asian plate – yet not more dense than the mantle below. This discrepancy in density led to the Indian subcontinent underlying Asia, leading to crustal thickening. Isostatic compensation took hold (Airy’s Isostasy), leading to a large continental root with the uplifted rock on top.

Map showing the location of the Tethys Ocean 200 million years ago (USGS).
Map showing the location of the Tethys Ocean 200 million years ago (USGS).

Evidence for this can be seen if you head from India towards Tibet. Initially, you’ll travel along the Gangetic plains, an alluvial deposit approximately 200m above sea level. Travel further north, and you’ll find the sub Himilayan Silwaliks, deposits of fluvial rock on the southern front of the Himalaya, where erosional rivers from the Himalaya deposit their load. 10-20km further, and you’ll reach the base of the lesser Himalaya; separated by the Main Frontal Thrust. This is the site of the main active fault in the Himalaya, the Main Boundary Fault, which we will return to later.

The lesser Himalaya are approximately 60-80km of low fossil content sedimentary and lightly metamorphosed rocks, containing a large amount of folding, faulting, and thrusting. As the Indian plate has subducted under the Asian plate, these rocks from the Asian plate have been exerted to a number of forces leading to the bending and buckling, and partial metamorphosis, seen. Past this sequence we arrive at the base of the Higher Himalaya, marked by the currently inactive Main Central Thrust. Above, the up to 10km thick highly metamorphosed rocks of the higher Himalaya. Typically, rocks which are found here are kyanite-sillimanite grade gneisses. More information on the geology of the region can be found here.

The structural geology of the region plays an important role in the lives of those living there. In physical terms, the movement of the Indian plate and activity on the faults present can lead to earthquakes causing large, lasting damage to towns and villages in the region. As the Indian plate moves, the faults (such as the Main Boundary Fault) can lock, leading to buckling. When sufficient energy is present in the system it slips – the energy is then released, producing large earthquakes. One such earthquake was the April 2015 earthquake in Nepal, killing nearly 9,000 people.

Mountain ranges such as the Himalaya also affect the local population in a mythological and spiritual way. In Nepal, the isolated peak of Machapuchare (Fishtail) is believed to be one of the homes of Hindu God Shiva. As such, it is impossible to acquire a permit to climb to the summit – the closest official attempt in 1950 was a British expedition, which out of respect did not attempt to reach the summit.

Shiva – the creator, the nurturer and the destroyer – Shiv Purana, 1.2.10 Shabda-Brahma Tanu.

Shiva is presented as the Creator and Destroyer, which makes the Himalayan mountain range a very apt place for Him to take up residence; where both creating, and destruction is occurring.

Other mountains are similarly encased in mythology. Mount Everest is believed by Tibetan Buddhists to have been host to Miyolangsangma, Goddess of Inexhaustible Giving, and remains as her palace and playground.

While climbers to Mount Everest are guests, the mountains can be treacherous. The summit of Everest is covered in dead bodies, with 290 visitors having died. The deadliest of these mountains, Annapurna, has a fatality rate of 34%, the highest in the world – likely due to large ice cliffs and columns of ice known as seracs.

The mountains are not just harmful to humans. While in the lower regions they are occupied by animals such as the bears (such as the Himalayan Black Bear), wolves (Himalayan Wolves), deer (Great Himalayan Musk Deer), the higher reaches above tree line at 2500m are less accessible due to restricted levels of oxygen coupled with colder climates, and harsh geography. The Himalayan mountains contain the third largest body of ice on the planet after the Arctic and Antarctica, which presents an interesting struggle to the organisms who end up living there.

Overall, then. The Himalaya are an interesting feature on the surface of the Earth, affecting those who live on and around them. Religions and mythologies have built up surrounding them, likely in part due to the danger they present both to us and to other animals on this planet.