By : Lily Ganote

History of Pangaea Alfred Wegener originated the theory of Pangaea. Pangaea means “ All Lands” and existed during the Carboniferous period and is believed to have started to separate late into the period, about 300 million years ago. His theory was controversial because of the fact that it didn’t explain why the continents moved. There was also another theory about the continents movement. This theory was that the Earth was going through cycles of heating and cooling. The heating and cooling causing expansion and contraction of the land masses. People who believed this theory were called anti - mobilizes. While Alfred was a German geologist, he also was accomplished in other sciences. Of the few he went and got a Ph. D in astronomy. I believe this helped him because he knew a lot about the other planets and how they have changed over time. Because of this knowledge he could make a better hypothesis about the Earth and it has changed over time as well. Alfred also had an interest in meteorology and climatology. Their were to major people that helped in the recognition of Wegener’s theory. The South African geologist Alexander Du Toit supported Wegener's theory because it was an explanation for the close similarity of fossils between Africa and South America. The Swiss geologist Émile Argand also agreed because she saw continental collisions as the best explanation for the folded and buckled strata that he observed in the Swiss Alp.

Convergent Boundaries Convergent boundaries occur all over the world but mainly along coast lines. A convergent plate boundaries are places where the lithosphere plates are moving towards one another. An example of a convergent boundary would be on the Washington – Oregon coastline. The Juan de Fuca oceanic plate is being subducted underneath the westward moving North American plate. Seduction is when an oceanic plate is forced down into the mantle by a thicker but less dense continental-land-plate. Convergent boundaries can cause many hazards to our environment Some of these hazards are earthquakes, volcanoes and crustal deformation. Earthquakes and volcanoes can then cause trenches to form in the earths crust.

Divergent Boundaries Divergent plate boundaries are places where plates are moving away from another plate. This occurs above rising convection currents, the rising current than pushes up on the bottom of the lithosphere, lifting it and flowing laterally beneath it. The flow causes the plates materials that are above to be dragged along in the direction of the flow. At the crest of the uplift, the overlying plate is than stretched thin, and ends up breaking and pulling apart. When a divergent boundary occurs beneath the oceanic lithosphere, the rising convection current below lifts the lithosphere producing a mid-ocean ridge. Divergent boundaries can cause many harms to our planet. Divergent boundaries cause trenches, mud and landslides and volcanoes because of the forming hole in the earth. One well known divergent boundary is the Mid-Atlantic Ridge. This submerged mountain range, that extends from the Arctic Ocean, and beyond the southern tip of Africa, it is one segment of the global mid-ocean ridge system that encircles the Earth. The Mid-Atlantic Ridge moves about 2.5 centimeters each year or 25 centimeters every decade.

Transform boundaries Transform Plate Boundaries are places where two plates slide past one another. The gap or “fracture zone” created by the plates sliding is known as a transform fault. Most transform faults are found in the ocean basins and connect offsets in mid-ocean ridges. A smaller number connect mid-ocean ridges and subduction zones. there are to types of faults, transform and strike-slip faults. Transform faults can be distinguished from the typical strike-slip faults because the sense of movement is in the opposite direction then the other. A strike-slip fault is a simple offset. While a transform fault there are two plates moving away from the spreading center of a divergent boundary. The most famous example of transform boundary is the San Andreas Fault Zone in North America. The San Andreas causes many earthquakes and mud/ landslides.

Real World Connections We live on the North American Plate. We are surrounded by the Juan De Fuca Plate, the South American Plate, the Caribbean Plate, the Eurasia Plate, and the African Plate. Here in Ohio we are not in much danger, being in the middle of the plate with no volcanoes or mountains, although the Appalachian Mountains are close. In the middle of the North American Plate there are no transform, convergent, or divergent boundaries. The last earthquake in Ohio was on April 18, The United States Geological Survey reported the earthquake occurred at 5:36 a.m. The earth quake didn’t start in Ohio it started in Illinois near the Indiana Border. It was centered six miles from West Salem, Illinois. It was a 5.2 magnitude earthquake. Columbus, Ohio is raked one of the highest places in the U.S, of the 50 most populated, at risk of a natural disaster, according to a 2009 study. Why you may ask? It is because of it high risk of floods, winter storms, tornadoes and the occasional earthquake. Five cities in California are on the top 10 list. In the very distant future I think the San Andreas Fault will be even larger and it earth quakes will be even worse. I also think that the mountains will move from the spots they are in now.

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