Download Plate Tectonics - NagelBeelmanScience

By: Maddie O’Toole
Alfred Wegener, who was a geologist and a meteorologist, proposed the
1st theory of continental drift. He made an hypostasis that about 200
million years ago there was one large supercontinent consisting of all of
Earth’s land masses, and it was called Pangaea which means all Earth and
was there in the Carboniferous time period. Not all scientists originally
believed in Wegener’s theory, because he didn’t have enough evidence or
exclamation for why the continents actually moved. He didn’t have
evidence for why the mountain ranges and other features didn’t continue
we’re the continents split or other things like that. Also some people
believed a theory that the planet was a molten ball on the inside and
nobody believed that the sides could cool enough once it cracked. Later,
some scientists started to believed Wegner’s theory because during the
controversial time of this topic they thought that the Earth is going
throughout heating and cooling cycles which caused expansion and
contraction of the land masses.
A convergent boundary is a deforming region where 2 or more plates
move toward each other and collide, and one is pushed down underneath
the other plate. Earthquakes and volcanoes are common near convergent
boundaries as a result of pressure, friction and plate material melting in
mantle. An example of a convergent boundary is the boundary between
the Pacific and Juan de Fuca Plates. It’s marked by a submarine
mountain chain which is known as Juan Fuca Ridge which is about 500
kilometers long. Most trenches are caused by the movement of tectonic
plates.
Divergent boundaries are linear features that lie between two tectonic
plates moving away from each other. This occurs above rising
convection currents. The current then pushes up at the bottom of the
lithosphere and causes plate material to be lifted along the direction of
flow. This occurrence causes a mid ocean ridge, which is an area of the
seafloor that is higher then the surrounding area. Divergent boundaries
sometimes do produce earthquake activity, and if the boundaries form
on continents then it can make a line of volcanoes.
Transform boundaries are where two plates slide past one another.
When the two plates slide past each other no plates are added destroyed.
The fraction zone is what forms transform plate boundaries, and this zone
is known as a transform fault. Large earthquake activity is usually what
occurs around transform boundaries. When an earthquake takes place
this causes landslides and mudslides.
The US is mostly located on the North American Plate. The Pacific Plate
borders most of the US, and so does the North American Plate and the
Juan Fuca Plate. We are in danger of serious hazards because California
is on the North American Plate and the Pacific Plate, which is a major
fault line, and it is called the San Andreas Fault. The San Andreas Fault is
hazardous because it can cause major earthquakes. Based on what I have
learned about plate tectonics I think that in the distant future, plate
tectonics are going to make the continents form together again.
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http://www.ucmp.berkeley.edu/geology/techist.html
http://geology.com/nsta/divergent-plate-boundaries.shtml
http://www.kidsgeo.com/geology-for-kids/0045-divergentboundaries.php
http://geology.com/san-andreas-fault/
http://en.wikipedia.org/wiki/North_American_Plate
http://vulcan.wr.usgs.gov/Glossary/PlateTectonics/description_plate_t
ectonics.html
http://www.ucmp.berkeley.edu/geology/techist.html
http://scign.jpl.nasa.gov/learn/plate2.htm