The Himalayas are home to the largest mountains on earth and lie between the Indian subcontinent and the rest of the Asian continent. They are actually getting slightly taller every year as they are pushed upwards by two tectonic plates pushing against each other. Many climbers attempted climbing the highest peaks including Mount Everest in Nepal and K2 in Pakistan, but few visitors know what they’re walking on when heading for the top.
The world was once made up of one land mass called Pangea which over time split up into different parts. The Indian plate was one of these pieces and the Eurasian plate above was another. Between them existed a sea, called the Tethys, until the Indian plate, over millions of years, moved towards the Eurasian plate, crinkling and pushing up the land between at the bottom of the sea to become the Himalayas.
The vast majority of the rocks found in the Himalayas are sedimentary rocks. They are formed, as the name suggests, when sediment in water falls to the bottom and is compacted into rock over time and as a result of the pressure of more and more layers of sediment on top. The sedimentary rock in the Himalayas was formed at the bottom of the Tethys Sea before being pushed up. This is the reason sea fossils can be found high up in the Himalayas. Shale, marble, limestone and sandstone are common varieties of Himalayan sedimentary rocks.
The two tectonic plates ramming into each other to form the Himalayas are the same density so rather than one plate going under the other, they are pushing into each other and thickening. Parts of both are subject to huge pressures which compacts other rocks into much harder rocks. The result is metamorphic rocks. Different types of schist and gneiss are metamorphic rock types found in the Himalayas.
Igneous rocks are formed when molten rock cools and hardens. They are often formed as a result of volcanoes, but there are no volcanoes in the Himalayas and the igneous rocks here were formed underground and have been pushed up. Granite is a common form of igneous rock and is found in certain places in the Himalayan range, often containing quartz, mica and feldspar.