Mountain Building

Wow, where did the time go? I suppose my life has been much like the process of mountain building with a few minor and major quakes and pressures and eruptions that have led up to the building of new horizons for me.
And that is exactly what goes into the building of mountains. Check out this site on mountain building.

This takes place where divergent boundaries are found. Some of you may know these as constructive boundaries. This is where the plates are moving apart, allowing pressures from beneath the surface to push upwards.

The photograph above is taken from my back yard of the Oquirrh Mountains that surround the western side of the Salt Lake Valley. For a better understanding of this process, visit the links above by right clicking and select to open in a new window or tab.

Subduction and Oceanic Trenches

Previously we discussed Plate Tectonics. You may be wondering what happens when two of these plates collide. It's called subduction. When these two plates meet, the heavier or older of the two will slide beneath the younger, less dense plate. The subduction zone is called a destructive plate boundary.

The photo above depicts subduction and oceanic trenches. As you can see the heavier plate is rotating downward and underneath the other plate towards the asthenosphere. This causes faulting to occur in which rocks are broken down and displaced along the fractures. When a long deep and narrow depression is created from this process it's called an Oceanic Trench.

Remember, as the plates move downward they move closer to magma flows. The intense heat from magma causes rocks to be more bendable. So how does this all tie together with what we've learned so far? That's a pretty complex topic but we will break it down into bite sizes pieces. Kind of like subduction right?

Right. have you ever heard of the "Ring of Fire" and I don't mean the Ring of Fire in Finding Nemo, either. If you haven't, here's a clue.

Think Volcanoes. Destructive plate boundaries are commonly marked by volcanic activity. That is to say, that not only does plate movement and subduction cause earthquakes. volcanoes are often found above the subducting plates. Here is a map showing the Ring of Fire.

The Ring of Fire is a ring of volcanoes (more horseshoe shaped really) located in the Pacific Ocean. They are a result of the oceanic lithosphere being subducted.

Right, so you know how I like to give you links to other sites that are more specific and have more information? Well, here's another link for you. Remember to right click and select to open in a new window: Dynamic Earth Be sure to visit and don't be afraid to google the topic of subduction zones to learn more in depth about the topics discussed here.

The earth and how it was formed and its continually changing is a fascinating subject. At this point we've explored briefly subduction and destructive boundaries along the oceanic plates. Next time, we will have a look at constructive boundaries and mountain building.