The birth of a mountain range is connected with the phenomena that occur underneath the ocean trenches. We have seen that the Earth's surface is moving from the oceanic ridges towards the trenches, and with this movement, is taking the land masses attached to them along for the ride. Now, let's consider two continental land masses: the trench on the edge of one mass is swallowing the ocean crust that separates it from the other one. Slowly, the ocean becomes smaller as the land masses move closer and closer together until the second one reaches the edge of the trench. The Earth's surface that constitutes the continents is much lighter than the bottom of the ocean, therefore the continent is not swallowed up by the ocean but continues to move inexorably towards the other one. It is a slow, but inexorable process: the light marine sediments, some surface "pieces" and the rocks of the two continents are pressed in this strong vice until they curl, break and rise up. Where there once was an ocean, there is now a mountain range. However, the oceanic rocks remain to testify that there was an ocean: in all the principle mountain ranges around the world, there are very special green and black rocks that are quite different from the other rocks on the continents. These rocks are the so-called "green stones" or ophiolites, and they are identical to the rocks that are actually at the bottom of the oceans: they are the remnants of the past oceans. This is how the tallest mountain range in the world, the Himalayas, was created: a small continent, India, collided with Asia about 40-50 million years ago. The Himalayas are nothing but the "scar" of that collision.
The birth of a mountain range is connected with the phenomena that occur underneath the ocean trenches. We have seen that the Earth's surface is moving from the oceanic ridges towards the trenches, and with this movement, is taking the land masses attached to them along for the ride. Now, let's consider two continental land masses: the trench on the edge of one mass is swallowing the ocean crust that separates it from the other one. Slowly, the ocean becomes smaller as the land masses move closer and closer together until the second one reaches the edge of the trench. The Earth's surface that constitutes the continents is much lighter than the bottom of the ocean, therefore the continent is not swallowed up by the ocean but continues to move inexorably towards the other one. It is a slow, but inexorable process: the light marine sediments, some surface "pieces" and the rocks of the two continents are pressed in this strong vice until they curl, break and rise up. Where there once was an ocean, there is now a mountain range. However, the oceanic rocks remain to testify that there was an ocean: in all the principle mountain ranges around the world, there are very special green and black rocks that are quite different from the other rocks on the continents. These rocks are the so-called "green stones" or ophiolites, and they are identical to the rocks that are actually at the bottom of the oceans: they are the remnants of the past oceans. This is how the tallest mountain range in the world, the Himalayas, was created: a small continent, India, collided with Asia about 40-50 million years ago. The Himalayas are nothing but the "scar" of that collision.
