P LATE T ECTONICS By Lauren Butterfield 4 th Period By Lauren Butterfield 4 th Period

C ONVECTION C URRENTS There is one force that is behind plate tectonics. This force is convection currents. Convection currents rise and fall. As the material beneath the Earth’s crust heats up, it rises, and when it gets farther from the core, it cools and falls, starting the process over again.

B OUNDARIES There are three types of boundaries: convergent, divergent, and transform. After that, some of them are broken into even smaller categories. There are three types of convergent boundaries. They are ocean to ocean, continent to continent, and ocean to continent.

C ONVERGENT BOUNDARIES Like I stated earlier, there are three types of convergent boundaries. Plates that meet at a convergent boundary push against the other plate. When the two plates meet, a subduction zone is formed. This is when one plate falls beneath the other, and descends into the mantle where it is melted.

O CEAN TO O CEAN C ONVERGENT B OUNDARIES The first type of convergent boundaries is ocean to ocean. Ocean to ocean is when two oceanic plates meet together. They push against each other, to form island arcs, much like Japan. (Please wait, animation may take time to play.)

C ONTINENT TO C ONTINENT B OUNDARIES The second type of boundary is Continent to Continent. With these boundaries, two continental plates meet together to form tall folded mountains, such as the Himalayas.

O CEAN TO C ONTINENT B OUNDARIES The third type of convergent boundary is Ocean to Continent. At this boundary, an oceanic and continental plate meet to form volcanic mountain ranges. An example of this is the Cascade Mountain range is Western North American. (Please wait, animation may take time to play.)

D IVERGENT B OUNDARIES A divergent boundary is when two plates pull apart. At a divergent boundary, lava forces its way between the two plates, and forms mid-ocean ridges.

T RANSFORM B OUNDARIES At a transform boundary, the two plates slip or slide past one another. Because of this, they are sometimes known as strike-slip boundaries. When these two plates move past each other, they move the land, creating that such as the San Andreas Fault.

H OT S POT A hot spot is that like Hawaii. A hot spot is when there is an especially hot piece of the mantle, that has convection rising to the surface. The heat rises, forming islands in the water. Over time, the plates move, making the hot spot appear to be in a new place on the earth’s surface, but really, it is the plates that are moving, which is why Hawaii was formed like it was.

C ONVERGENT B OUNDARIES AND T HEIR A FFECT Convergent boundaries affect Earth in many ways. These are just a few. Geosphere The geosphere is affected by the lava flow from the volcanic mountain ranges. The ground can be covered in lava, making it rich, fertile farming ground. Biosphere When lava flows, it can wipe out plant and animal life, yet create much more. It makes it possible for new plants to thrive. Atmosphere The air surrounding a volcanic eruption can be damaged a lot when the ash and gas gets spewed into the air. It can be very hard to breathe, which can further affect the biosphere. Hydrosphere Nearby lakes, rivers, and any other water sources can and will be polluted when the pyroclastic flow covers the earth.

D IVERGENT B OUNDARIES A FFECT Divergent boundaries have few, but damaging affects on the environment. Geosphere At a divergent boundary, new land is formed, and old land is pushed back. This is called seafloor spreading. Biosphere The biosphere is affected because it can create and destroy plant life. As the old land moves away, it is pushed into ridges and plants are destroyed. Atmosphere This type of boundary does not do much to the atmosphere. It does however put gases from the mantle into the water, which rises into the air above. Hydrosphere The hydrosphere is affected much in the way the atmosphere is affected. Gases from the mantle which have pushed up in between the two plates finds its way into the water around the boundary.

T RANSFORM B OUNDARIES AND T HEIR A FFECT Divergent and convergent boundaries are not the only things that affect the environment, transform boundaries can be just as harmful. Geosphere At a Transform Boundary, the two plates are moving past each other. This can cause the land surrounding the fault to crack and break. Biosphere The life is affected because any plants that are in the way of the fault can be destroyed. Atmosphere The atmosphere is not really affected in this type of boundary. Hydrosphere The water can be affected because bits of rock can fall into the water after they have broken off of one of the plates.

H OT S POTS : H OW D O T HEY A FFECT ? Hot spots also affect the environment in many ways. These are just a few. Geosphere They affect the geosphere by creating new land. Biosphere The biosphere is affected because new land can be formed, which creates new habitats for many of earths different plant and animal species. Atmosphere As new islands are being created, gases can come up from the hot spot and be mixed into the air. Hydrosphere As the new land is formed, it is made in water. It becomes completely surrounded by water making it one or even two new islands.

B IBLIOGRAPHY Sources Images f