http://www.ucmp.berkeley.edu/geology/techist.html
Pangaea is a word that
means “all land”. The idea
that the earth used to be
one big super continent was
founded by Alfred Wegener
in 1912. He thought that
they all used to be
connected due to the fact
that a lot of coastlines on the
continents fit into each
other. Pangaea was thought
to be connected until the
late Carboniferous period,
about 300 million years ago.
That’s when the continents
started to break apart and
move away from each other.
Wegener was the first scientist to have the idea that the
all continents used to be part of one massive super
continent. The idea for the cause of mountain ranges of
his time was called, Contraction theory. It was a theory
in which scientists believed that the earth was once a
molten ball of metal and rock, and that during the
cooling process it crinkled, causing mountain ranges
and cliffs/trenches. Paleontological papers helped prove
Wegener's theory by proving that fossils of similar
species were found in areas close to where they used to
might have been connected. There was also evidence
that there might have been a land bridge between
Africa and Brazil. Wegener's ideas began to be
dismissed in 1929 and so did the idea that the earth has
a convection current.
http://www.ucmp.berkeley.edu/geology/techist.html
A boundary is a place where two continental plates either meet or go in
opposite direction of. The results of the continental boundaries are all different, it all
depends on the direction and force of the continental plates. The continental plates are
large masses of rock that slowly drift across the earth’s surface.
http://vulcan.wr.usgs.gov/Glossary/PlateTectonics/description_plate_tectonics.html
A convergent boundary is when two continental plates going in
opposite directions meet. One plate, the denser plate, is pushed under the
other. When this occurs volcanoes can form from the molten plate that is
subducted under the other plate. When the plate is put under the other
and is pushed into the asthenosphere, it melts and the molten rock is then
transferred to the surface through volcanoes. Mountains also can also
occur when the subducted plate pushes
the other plate upwards. A mountain
is a piece of land that is pushed at a
higher elevation than the surrounding
land. An example of a convergent
boundary is the boundary between
the Eurasian plate and
Indian- Australian plate.
http://vulcan.wr.usgs.gov/Glossary/PlateTectonics/description_plate_tectonics.html
A Divergent Boundary is when two continental plates
pull away from each other leaving behind a trench or valley, a
ravine where land is suddenly lower than the surrounding land.
In most cases it is where new materials are deposited. And
example the boundary between the Pacific and Nazca plate.
http://vulcan.wr.usgs.gov/Glossary/PlateTectonics/description_plate_tectonics.html
A Transform Boundary is when two continental plates going in opposite
directions cause friction between each other. The resulting friction can cause
earthquakes to happen. Throughout the process also, neither of the plates lose any
land. An example is the San Andres Fault in California. It is between the North
American plate and the Pacific plate.
Earthquakes are when two plates slide
Past each other like a transform
Boundary, the resulting friction is
Transferred through vibrations in
The ground. The results can be very
Dangerous or very mild.
http://www.gweaver.net/techhigh/projects/period1_2/Yellowstone/Plate%20Tectonics.html
Landsides can occur anywhere. They can be
activated by storms, earthquakes, volcanic eruptions, fires,
alternate freezing or thawing, and steepening of slopes by
erosion or human modification. They can be slow or fast, and
slow or rapid. They can be very dangerous to humans and
animals. And can cause a lot of costly damage.
Mudslides are rivers of rock, earth, and
other debris saturated with water. They develop
when water rapidly accumulates in the ground,
during heavy rainfall or rapid snowmelt, changing
the earth into a flowing river of mud or “slurry.” They can flow very rapidly and can cause
massive damage, striking with no warning.
http://www.fema.gov/hazard/landslide/index.shtm
We live on the North American plate, and we are
surrounded by the Pacific plate, Eurasian plate, African plate,
South American plate, and the Nazca plate. The California
boundary, the San Andres fault, is at constant risk for
earthquakes because it is a transform boundary. The United
States may suffer damages from the Pacific plate. If the Pacific
plate starts to move into the North American plate, it will cause
problems because the transform
fault is right on the east border of
the East coast. That includes
California, Washington, Oregon,
and Alaska.
http://denali.gsfc.nasa.gov/dtam/images/schematic_map.jpg