How does the plate tectonic theory explain mountain belt formation?

Question

How important are climate and erosion in explaining how mountain belts are formed?

Answer 1

Tectonic belts can be volcanic or collision related.

Volcanoes:
There are several processes in Plate Tectonics that cause volcanism, but they result in two main types of volcanism.

Volcanism in subduction is caused by volitals, like H2O, CO2. These are carried down by the plate, mainly in the form of weak minerals. These minerals break down with pressure and temperature into stronger minerals that don't contain water and carbon dioxide. The leftover gases and liquids travel into the mantle (the mantle wedge) and hydrate the mantle, causing melting. The melt rises and then... volcano!

The other main cause is from rising mantle material, which forms decompression melting. Basically, hot mantle is kept from melting by the pressure of the earth at depth. When this material rises, the pressure drops much faster than the temperature, and thus it partially melts. This mainly occurs at divergent boundaries and hot spots, which are areas in plate tectonics that have rising materials or spreading.

Mountain Belts:

Non-volcanic mountain belts are caused by compressive stress in plate tectonics. This can be 1. fold and thrust belts in highly compressive subduction zones (almost always from oceanic beneath continental subduction, e.g. east Andes, Rockies) or 2. continental-continental collisions (e.g. Himalaya, Appalachian).

Answer 2

When plates collide one is subducted under the other, or it is partially subducted in the case of continent-continent collisions. The theory of Plate Tectonics provides a mechanism, the convection of the mantle causing plate movements and collisions. Climate and erosion is very important in the formation of mountains because with much erosion (due to proper climate conditions), material can be deposited in a forearc basin, which leads to the increase of depth in the forearc basin, which allows for the increased height of mountain belts. Erosion can deposit material away from the forearc basin, in which case the mountains are reduced in height only.

Answer 3

Climate influences erosion in obvious ways. For instance, if there
is a wet climate, there will be erosion due to abundant running
water at lower elevation and heavy glaciation at higher elevation.
If the climate is arid, erosion will be much slower. Tectonics affects climate because if a region is uplifted to a high elevation, the climate there will be cold and glaciers can develop. With less uplift and lower mountains, erosion will be mainly due to running water.
A moist climate can also result in heavy vegetation at lower elevations, which would tend to retard erosion.
Erosion and climate can influence tectonics as well. For example, the extent and type of erosion can help determine whether a highland grows higher or lower with time. If a high plateau, dissected by only a few valleys, undergoes erosion, the plateau is eroded downward uniformly.
Following erosion, isostasy results in
the plateau floating upward but not up to its original level. Its average surface, which essentially is its actual surface, is at a lower elevation than before erosion took place. If erosion carves many deep valleys and leaves relatively few mountains between the valleys, the entire regional block will have less mass and will float isostatically upward. As in the case of the plateau, its average surface would rise to a level
lower than before erosion; however, its average surface is somewhere between the peaks and bottoms of valleys. Although the average height of the block rises to a level below its previous average height, the mountains rise to heights greater than before.
Climate enters the picture because, interacting with tectonics, it
helps control the type and extent of weathering that takes place. For instance, heavy precipitation takes place in the Himalaya because of the flow of very humid air from the south during the summer monsoon. At the higher elevations, the precipitation in the form of heavy snowfall contributes to extensive and very active glaciation.

Answer 4

When the plates crash into each other, they form mountains. Climate and erosion make mountains smaller and smoother, they don't form mountains.

Answer 5

When 2 plates collide, one slides over the other, causing both to warp. The one on top bends upward, while the one on bottom bends downward. This is kind of a simplistic explanation, but I hope it makes it easier to understand the collision aspect.