The Mid-Continent Rift appears to have made it about as far as possible without succeeding, based on the large volume of magma (new crust) in the rift. The Mid-Continent Rift is considered a failed rift because it did not create an ocean. If continental rifts are successful, a new ocean will be formed (such as the Atlantic Ocean). This is where the North American continent tried to split apart and create a divergent boundary. The feature that we are studying is the Mid-Continent Rift. For our study (SPREE) we are interested in the beginning stages of the Wilson cycle, called continental rifting. This balancing act of the Earth’s crust has been named the Wilson cycle (Figure 5). Here fresh lava reaches the surface, creating underseas mountains, volcanos that sometimes reach the surface as in Iceland. Divergent boundaries occur at the mid ocean ridges.
This upwelling of magma splits and push the earth's crust apart. Hence there is a balance between divergent boundaries creating crust and convergent boundaries removing it. A divergent boundary is a place where the convection currents in the mantle move upwards. At convergent boundaries, portions of crust are subducted (go under another plate) this effectively removes portions of the crust from the surface of the Earth (Figure 4). Since the surface area of the Earth is unchanging, there must also be a way to get rid of crust. When tectonic plates move apart from one another, magma fills the gaps and creates new crust. Notice that a “gaps” forms at a divergent boundary as the plates continue to separate. Lastly, a divergent boundary is when plates move apart from one another. Plates that move toward each other form convergent boundaries. If the plates slide past one another, this is called a transform boundary. Imagine tectonic plates like blocks there are only a few ways these blocks can move relative to one another (Figure 3). Three types of boundaries exist for tectonic plates: divergent, transform, and convergent. differing from each other or from a standard. The seismograms contain information about the structure of the Earth along the path that the waves traveled. divergent: adjective moving or extending in different directions from a common point : diverging from each other. These records are known as seismograms (Figure 2). By installing earthquake-monitoring stations we are able to record ground motions from seismic waves. Earthquakes, which usually occur at the boundaries between tectonic plates, release seismic waves. The Earth’s outer shell, the crust, is composed of rigid tectonic plates that stick and slip past one another (Figure 1).
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