| MadSci Network: Earth Sciences |
To answer your question, I first want to cover a few basics about how mountain ranges are formed on Earth. Then I will talk about the highest mountains that exist currently on the face of the Earth and their rates of uplift and erosion. The short answer to your question is that the five highest mountains that exist today will still be the five highest mountains in 10,000 years. That is because, geologically, 10,000 years is a blink of an eye to the Earth. Mountain ranges grow for tens to hundreds of millions of years, depending on the tectonic setting they are in.
Mountains are indeed awesome and inspiring geologic landforms. In general on Earth, mountains are formed when two tectonic plates collide with each other. A good description of plate tectonics can be found at platetectonics.com where they have a very nice book set up to describe all manner of features surrounding plate tectonics as well as a number of useful photos (see link below).
There are two main types of plate collisions that form mountains: collisions between an oceanic plate and a continental plate and collisions involving two continental plates. Collisions involving an oceanic plate and a continental plate are called subduction zones because the oceanic plate (being made of denser material) slides beneath the continental plate. A mountain range is formed a few hundred miles inland on the continental plate from compression as the two plates come together. An example of this type of mountain range is the Rocky Mountains in North America and the Andes in South America – all along the western edge of the Americas, the Pacific Plate is sliding beneath the continental plates that the Americas sit on. Collisions involving two continental plates do not involve subduction because the two continental plates have the same density; therefore, neither one is likely to move under the other plate. Rather, huge mountain ranges are pushed upward as the two plates push together and crumple each other up, moving material higher and higher. An excellent and current example of this type of mountain range is the Himalayas, the highest mountains on Earth (although the Appalachian Mountains also formed in this manner).
As it turns out, every single one of the highest mountains in the world (defined as peaks higher than 8,000 meters or 26,247 feet) is located in the Himalayan Mountains in Asia (India, Tibet, China, Pakistan and Nepal). The Himalayas have been forming for the last 70 Million years (and therefore, are a fairly young mountain range on the Earth), but the story of their formation begins 225 Million years ago. Way back then, India was a large island on the Indo-Australian plate that had begun moving northward at about 15 cm/year toward the Eurasian plate (containing Tibet and China). At first, the denser oceanic plate containing India subducted beneath the Eurasian plate, but then India (composed of continental material and equal in density to the Eurasian plate) starting colliding with the Eurasian plate itself and did not subduct. Instead, the plate slowed its motion down a bit, to about 8 cm/year, the two pieces of continental crust began buckling as they continued to push together and the Himalayan Mountains began to form (about 70 Million years ago). This has continued for the past 70 Million years and is still going on today! In fact, the rocks at the top of the Himalayas contain fossilized sea creatures, indicating that these rocks used to reside on the bottom of the ocean that originally separated India and Eurasia. The University of Rochester has some wonderful descriptions of the growth of the Himalayas, including very descriptive sketches of India’s motion over the past 225 Million years (see links below).
Mount Everest, the highest mountain in the world, is still growing as India continues to push into Eurasia. Average growth in the Himalayas is 3-5 mm/year total as measured using the Global Positioning System (GPS) units that have been placed on the top of Mount Everest by scientists. This growth includes the uplift from the two colliding plates (about 1 cm/year) and erosion of the mountains (approximately 3 mm/year). Not only is Mount Everest growing higher every year, it is also being pushed in the north-easterly direction about 3 cm/year as India continues to move northward into Eurasia!
Because the five highest mountains in the world are in the Himalayas, and the Himalayas are some of the fastest growing mountains in the world, in 10,000 years these mountains will still be the highest in the world. In 100 Million years that may be quite different, as the history of the Appalachian mountains teaches us.
The Appalachian mountains in the eastern part of the United States formed in the same manner as the Himalayan mountains, when the African and North American continents collided about 500 Million years ago. The Appalachians are not nearly as high as the Himalayas anymore for two reasons: First, after the two plates had collided and pushed up the Appalachians (which would have rivaled the Himalayas), the plates rifted apart again, spreading open to create the Atlantic Ocean. Even now, the Americas are moving away from Europe and Africa a small amount every year! (Ah the wonders of plate tectonics!) Second, the Appalachians are older than the Himalayas. Once the two plates began pulling apart, there was no continuing pressure for the Appalachians to grow upward. Instead, erosion became the main player in the evolution of the Appalachian mountains and so they have been mostly erased from the Earth’s surface.
In perhaps a few hundred million years (depending on how the plate tectonics in that part of the world change), the Himalayas might suffer the same fate as the Appalachians and a new mountain range will rise up to become the highest in the world. Unfortunately, I can’t predict which mountains those will be (although there are many scientists actively seeking an answer to that question). A safe estimate would be that the largest mountains on Earth, the Himalayas, will hold that title for another few million years.
A great web resource for all sorts of information, data and images of the mountains of the world (including volcanoes) is the Peakware World Mountain Encylopedia (see links below). At this site, you can search for the highest mountains in the world, the highest mountains on each continent, in each state, etc:
Try the links in the MadSci Library for more information on Earth Sciences.