Whenever a child is asked to sketch an idyllic natural scene on paper, what emerges often contains two majestic mountains towering over the other elements in the artwork. Mountains, the natural behemoths composed of rock and earth, are spectacular backdrops for numerous natural and manmade events.
When herds of African elephants and wildebeest migrate across the Serengeti in Tanzania, the peak of Mount Kilimanjaro sits high above their timely march, setting a magnificent stage for ‘living with nature’. Likewise, the glitzy, fast-paced city of Tokyo plays out in mechanical harmony, ever-inspired by the divine presence of snow-capped Mount Fuji in proximity, while Mount Rainier watches over picturesque Seattle.
The world’s greatest mountain range -- the Himalayas -- with its crowning jewel, Mount Everest, have guided Nepal for generations. Everest, or Sagarmatha in Nepalese, is a symbol of veneration for the country’s people.
For times immemorial, humans have revered mountains, which have existed through a significant part of Earth’s evolution, with the oldest mountain range, Barberton Mountains in South Africa, estimated to be around 3.5 billion years old. However, mountains did not start forming widely until around 2 billion years ago, which is halfway through the Earth’s history.
Mountains are a result of the Earth’s geological changes. The planet moves and alters its topography as it ages, and mountains are a clear indication of this phenomenon. The evolution of mountains also shows that the Earth’s surface is irregular. Mountains form in innumerable ways. The collision of tectonic plates can lead to their edges getting folded, forcing the rock to develop into a mountain. Other phenomena, ‘subduction’, is when one plate ends up diving under the other, while yet another is when plates split.
Volcanism can also lead to mountain formation, with subduction zones often hosting them. Volcanic mountains are formed when magma from deep within the Earth erupts and piles up at the surface. Some examples of volcanic mountains include Composite cones or stratovolcanoes, such as Mount Fuji (Japan), Mount Cotopaxi (Ecuador), and Mount Vesuvius (Italy); Shield volcanoes, which have a gently sloping cone, and include Mauna Loa in Hawaii; Dome mountains, which are smooth and round, and are formed when magma is forced up between the crust and the mantle, but does not flow out (Eg. Navajo Mountain in Utah, the Chaitén lava dome in Chile, and Mount St Helens in Washington State); Cinder cone volcanoes, made up of cinders or small pieces of solidified lava; and the Mid-ocean ridge, which is an active volcanic mountain range under the sea. A lot of volcanic mountains may still be active lava zones.
Erosion can also aid mountain growth. For instance, when glaciers or rivers run off mountain slopes, they erode materials along their path. Geologists have also found that activity deep within the Earth’s crust and mantle may play a part in building mountains, in a process known as ‘orogenesis’.
There is no clear number of mountain ranges in the world, since there is a lack of consensus of what defines a mountain range. However, some prominent chains of mountains are worth describing. The Himalayas are among the youngest and tallest mountain ranges on the planet, beginning to form around 50 million years ago, when the Indian Plate collided with the Eurasian Plate.
When we mention ‘began’, it simply implies that the Himalayas are still rising at a rate of 5 mm annually, as the plates collide and change the geological makeup of the region they occupy. When the Indian Plate moved Northward after splitting from Gondwanaland, as part of the Continental Drift, and crashed into the Eurasian Plate, the land between the two plates was pushed upwards, creating some of the highest peaks -- Everest, K2, Kanchenjunga, Nanga Parbat, Dhaulagiri, Annapurna, and Mount Kailash. However, the collision slowed its progress by half, creating immense pressure and heat, which formed the Tibetan Plateau.