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Himalayan mountain range formation
Did You Know?
The theory of continental-drift, put forth by the German meteorologist Alfred Wegener in around 1912, is the most widely accepted theory that explains the formation of the Himalayas.
Stretching for approximately 2,900 km (1,800 m), the Himalayas are literally the roof-top of the world. These mountains, which are located between four countries: Pakistan, India, China, and Nepal, are the tallest on Earth.
Evening Dresses
The Himalayan mountain range is the only one on our planet that comprises mountain peaks which rise over a staggering 8,000 meters. The tallest one among them―Mount Everest―rises to a breathtaking 8,848 meters, making it the tallest mountain peak on Earth.
So what was it that caused these mountains to attain such enormous proportions, becoming bigger than anything on Earth? How were they formed? Let's find out.
Plate Tectonics
In geology, a plate is a large rigid slab of solid rock. It is believed that the outermost layer of the Earth is divided into a number of small and large plates that float atop the hotter, denser, and more mobile material underneath, which is driven by the internal heat of the Earth. As such, these plates too are in motion, albeit at much slower speeds.
The term tectonics in Greek means 'to build'. Together, the term plate tectonics refers to the theory which describes how the surface of the Earth, as we see today, was built by the motion of the plates underneath.
Presently, it is thought that there are seven giant plates and a few other smaller ones that are in motion relative to each other on the Earth's surface. All the continents and the oceans lie on top of these plates. However, millions of years ago, there may have been more or less of these plates.
Pangaea Formation and Break-up: Continental Drift
Nearly 300 million years ago, all the major continents that we see today: Asia, Africa, North America, South America, Antarctica, Europe, and Australia, were absent. Instead, there was only a single giant super-continent, known as the Pangaea, which was located predominantly in the southern hemisphere of the Earth.
Pangaea was formed due to the movement of tectonic plates. It is believed that millions of years ago, giant accumulations of rock debris that spread over the tectonic plates were brought together when the plates moved towards each other. This caused the amalgamation of these debris into one giant debris, which gave rise to the Pangaea.
However, the movement of the plates continued on even after this. As a result, this super-continent began disintegrating into distinct pieces, each carried atop moving tectonic plates. Some of these pieces moved apart, while others collided and combined with one another, forming the continental landmasses that we see today.
How the Himalayan Mountains were Formed
Several million years ago, the grand Himalayan mountain range that we see today, did not exist. The Asian continent stood where it is today, but the Indian subcontient was nowhere in its vicinity. India, in fact, was an island floating near the coast of Australia.
Around 220 million years ago, when the Pangaea was breaking apart, the landmass of India, carried atop the Indo-Australian plate, began its slow migration northwards, towards the Eurasian plate on which the massive continent of Asia lay.
India Asia Collision
Collision of India and Asia
Nearly 80 million years ago, India was located 6,400 km (4,000 m) to the south of the continent of Asia. Over the span of the next several million years, India kept on traveling north, at an estimated rate of 5 - 15 cm/year, until it finally collided with Asia.
Before this collision took place, there existed a vast sea, known as the Tethys, which stretched latitudinally on the site that is presently occupied by the Himalayan mountain range. As India closed-in upon Asia, several rivers from it, in addition to those from Asia, began depositing large amounts of sediments into the seabed of the Tethys which lay in the middle. This large-scale deposition made the Tethys very shallow.
Approximately 55 million years ago, India began closing-in on Asia, covering up the Tethys sea. When the two landmasses finally collided, 10 million years ago, the Tethys sea was completely closed. Due to the enormous impact, the already shallow seabed, which by now had a large accumulation of sediments, rapidly folded and was elevated, rising up high and forming longitudinal ridges and valleys. This was the birth of the Himalayas.
As India continued its northward ascent, it began to wedge itself underneath the Asian continent. This happened because the northern coastline of India was denser and much more firmly attached to the seabed, as compared to Asia. Therefore, when these gigantic landmasses collided, India wedged itself underneath, causing the softer soil of the southern coastline of Asia to be pushed upward, rather than the other way round. This pushed the Himalayas, along with the entire Tibetan region upwards, further adding to the height of this enormous mountain range.
Tectonic Plates Collision
Formation of the Himalayas
As the Indian subcontinent continued pushing against Asia, the Himalayas continued to rise. This mountain range rose and spread very rapidly; much faster than most other mountain ranges on the Earth. In fact, the Himalayas are still growing even today. Everest and its siblings are known to grow by a few centimeters each year. This is in contrast to many other mountain ranges, such as the Appalachian Mountains, which were formed around 300 million years ago, and are actually becoming smaller due to erosion.
The reason why the Himalayas are still growing is the same as the one behind its formation - the movement of tectonic plates. The plate carrying India is still moving northwards, as is evidenced by the frequent earthquakes that occur in and around the surrounding region. Therefore, as long as this tectonic activity continues to take place, the Himalayas will probably continue to rise.
Now, if you were to calculate the tentative height of the Himalayas based on its current rising rate for the nearly 40 million years of its existence, you would find that it should be around 400 km tall! To put things in perspective, the International Space Station orbits the Earth at a height between 300 - 400 km (185 - 250 m). So why was it that these already gigantic mountains have not reached the mammoth proportions that the calculations predict?
One of the reasons is that, the rate of vertical growth of the Himalayas over the years has been variable, and some of force originating from the push of India against Asia has been subverted in favor of horizontal growth and expansion. The other likely reasons are the Earth's gravity and erosion, which have significantly reduced the growing potential and the height of the Himalayas.
The Future of the Himalayas
Owing to the continued northward motion of India, the Himalayan region remains geologically active, and continues to rise. Scientists believe that this rate of growth is likely to remain constant for the next 5 - 10 million years. This fact allows us to get a fair estimate of the development of this mountain range, and its effects on the surrounding region in the coming future.
Ten million years from now, India will plow an estimated 180 km into Tibet. Nepal lies between the lower boundary of the Himalayas and to the upper border of the plains of India. Due to India's motion, in the distant future, Nepal will cease to exist, but the Himalayan mountain range will remain, and continue to advance on India.
Evening Dresses
Continued geological activity will cause frequent earthquakes in this unstable region. The physical structure of this mountain range will comprise large mountains in the north and smaller ones to the south. They will continue to grow, and also be eroded at the same time. However, the net effect will most likely be that, the Himalayas will get bigger and even more spectacular with time.
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