The Rock Cycle, Plate Tectonics, and You James Martin Click to Begin

What is solid? Have you ever thought about how your local environment was created? Or what forces of nature were required to build the mountain and river valleys? What’s the most solid object you can think of? A door? A diamond? How about the Earth itself? What if I told you the earth’s crust was nothing but pieces of land, floating on a liquid and in a constant state of pressure, ready to move at any moment; trapped in a perpetual cycle of heating and cooling; continuously recycling itself? Would you believe me? What if I told you rocks could float? Would you believe that? What if I told you all of these things were related? Well, get ready to believe….

Plate Tectonics Plate Tectonics is a scientific theory that describes the large-scale motions of Earth's lithosphere or outer crust. The model builds on the concepts of continental drift, developed during the first few decades of the 20th century. The theory become commonly accepted after the concepts of seafloor spreading were developed in the late 1950s and early 1960s. On Earth, there are seven or eight major plates (depending on how they are defined) and many minor plates. Where plates meet, their relative motion determines the type of boundary: convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries.

Here is an example of the different types of plate boundaries. Transform boundaries (Conservative) occur where plates slide or, perhaps more accurately, grind past each other along transform faults. The San Andreas Fault in California is an example of a transform boundary exhibiting dextral motion. Divergent boundaries (Constructive) occur where two plates slide apart from each other. Mid-ocean ridges and active zones of rifting are both examples of divergent boundaries. Convergent boundaries (Destructive) (or active margins) occur where two plates slide towards each other commonly forming either a subduction zone (if one plate moves underneath the other) or a continental collision (if the two plates contain continental crust). Deep marine trenches are typically associated with subduction zones. The subducting slab contains many  minerals, which release their water on heating; this water then causes the mantle to melt, producing volcanism.

Click the image below to open a website containing animations of the plate boundaries in action.

The Rock Cycle With all this information about plate tectonics and plate boundaries, you might be asking yourself how this relates to rocks. Well, here’s your answer…. All rocks are classified based upon the method in which they are formed and one of the classifications (Metamorphic) is formed when rock material is super heated under intense pressure inside the Earth, but does not melt. This material is then brought to the surface via volcanic eruptions or exposure due to erosion, which is part of the Water Cycle. The other two classifications are: igneous and sedimentary. Igneous rocks are formed when magma from a volcanic eruption cools and sedimentary rocks are formed over time by the weathering and compressing of fine particles of sand and dust. Clip the image above to watch a short video NASA made about the Rock Cycle.

Click on the picture to the left to follow Rocky’s Journey through the Rock Cycle. Take a few moments to take the quizzes too.

Igneous Rocks Formed by slowly cooling; thereby allowing the molten material to crystalize. Violently expunged during a volcanic eruption. Contains micro air pockets which allows it to float.

Sedimentary Rocks Formed over time by the compressing of; sand, dirt, and other organic material.

Metamorphic Rock Sedimentary or Igneous rocks that have been transformed due to heat and pressure.

Now let’s take a short quiz and see what you’ve learned….

The Earth’s Surface is a solid non-moving mass. True False

Incorrect. Please try again.

Correct. The Earth’s surface is made of several tectonic plates that are constantly moving ever so little; shifting and pushing against each other until the pressure is released through earthquakes.

Which of the following type of rock is formed by super heating the material until it melts? Metamorphic Igneous Sedimentary

Incorrect. Please try again.

Correct. Igneous rocks are melted material that is allowed to cool Correct. Igneous rocks are melted material that is allowed to cool. If cooled slowly, they form crystals and take on a shiny, glossy appearance. If cooled rapidly, they can become hard and brittle and can contain air bubbles, allowing them to float.

Which rock is created by massive heat and pressure, but is never melted? Metamorphic Igneous Sedimentary

Incorrect. Please try again.

Correct. Metamorphic rocks are igneous and sedimentary rocks that are super heat and are then transformed by intense pressure. This heat and pressure cause the rock to create crystalline formations within the rock, without changing the composition.

Plate Tectonic, the Rock Cycle, and the Water Cycle play major roles in the creation of land formations and seismic active? True False

Incorrect. Please try again.

Correct. Plate Tectonics, the Rock Cycle, and the Water Cycle play major roles in the development of mountains, valleys, and all other land formations. Through a combination these three components, the surface of the Earth is in a state of permanent change, but it can only be measured over the long view of time.

Or evidence of transform plate movement while driving down the road.. Congratulations! Now that you have a basic understanding of what it takes to make mountains and rocks, why not take a walk outside and begin to look at your environment from a different perspective. Perhaps you’ll see mountains formed in the depths of the ocean, but lifted to the sky by converging plates. Or evidence of transform plate movement while driving down the road..

Or maybe, you’ll finally understand how a river flows backwards and creates a lake… Click the image to read about the New Madrid earthquakes of 1811-1812 that formed Reelfoot Lake.

References Plate Tectonics - http://en.wikipedia.org/wiki/Plate_tectonics Plate Tectonic Animation - http://www.classzone.com/books/earth_science/terc/content/visualizations/es0804/es0804page01.cfm?chapter_no=visualization NASA eClips Video on the Rock Cycle - http://www.nasa.gov/audience/foreducators/nasaeclips/search.html?terms=%22Our%20World:%20The%20Rock%20Cycle%22&category=0000&disp=grid Rocky’s Journey - http://www.oum.ox.ac.uk/thezone/rocks/cycle/ All still Images were found using image search on google.com or were created using screen captures.