NAME__________________________________________________________D_____________P_____
Plate Tectonics Guided Notes
http://www.learner.org/interactives/dynamicearth/drift2.html
In the early 1900s, the German scientist
________________________________________________ noticed
that the coastlines of _____________________ and ___________________
looked like they might fit together. He also discovered
______________________ that the same ___________________ and
_____________________________ _______________ were found along
the coasts of these continents, although they were now
Scientist Alfred
Wegener
______________________ by vast _______________________. In
addition, he noticed that geologic formations, like
______________________ ____________________, on the two continents also
________________________up.
In 1915, Wegener published his book, The Origin of Continents and Oceans, suggesting that the
earth's _________________________ were once __________________ together in one large mass.
He called the original landmass (or supercontinent) "______________________," the Greek word
for "___________ _____ ___________." According to Wegener, over time "Pangaea"
________________ __________ and the different landmasses, or continents, _________________
to their current locations on the globe. While other scientists of the time vehemently rejected
Wegener's ideas, they became the basis for the development of the __________________ ______
______________ _________________.
Continents on the Move
200 million years
ago
135 million years
ago
65 million years ago
50-40 million years
ago
Pangaea begins to
break up and splits into
two major landmasses
— Laurasia in the
north, made up of
North America and
Eurasia, and Gondwana
in the south, made up
of the other continents.
Gondwana splinters
further — the South
America-Africa
landmass separates
from the AntarcticaAustralia landmass.
Major rifting of
Laurasia, with the
North American
landmass separating
from Eurasia.
Greenland separates
from North America.
The Indian landmass
breaks away from the
Antarctica-Australia
landmass.
South America and
Madagascar separate
from Africa.
Australia separates
from Antarctica and
moves north.
The Indian landmass
collides with Asia.
The modern ________________ ______________
____________, which has become widely accepted since the
1960s, states that the earth's outer layer,
or ____________________, is broken into several large slabs
called ______________________. These plates, which hold
the continents and oceans, are_________________ but
________________________ _________________around the
planet. The movement of the plates not only supports our understanding that continents are not fixed
and moved over time, but also ____________ how and _____________
________________________, ________________________, and other geologic events occur.
Click
Continents Over Time
See if you can trace how the earth’s continents have shifted over time.
Complete the activity.
1. How many times did it take you to get it correct?__________________
2. What clues helped you figure it out?
3. What is the name of the new continent 250 million years into the future
________________________________________________________________
Check in with Miss Golden before moving on.
Plates & Boundaries
The earth's continents are constantly moving due to the motions of the tectonic plates. Closely
examine the map below, which shows the 15 major tectonic plates.
As you can see, some of the plates contain continents and others are mostly under the ocean. The type of crust
that underlies the continents is called ____________________ _________, while the type found under the
oceans is called _________________ _______________. Continental crust is ___________________ —
about 20 to 40 miles (35 to 70 km) thick — and usually____________ than oceanic crust, which is only 4 to 6
miles (7 to 10 km) thick. All the plates have names, usually referring to landmasses, oceans, or regions of the
globe where they are located.
The border between two tectonic plates is called a _________________________. All the tectonic plates are
constantly moving — __________ ______________ — around the planet, but in _____________
________________ ________________. Some are moving ________________________ each other, some are
moving _____________________, and some are __________________ _______________ each other. Because
of these differences, tectonic plate boundaries are grouped into three main types.
1) Fill in your chart on WS How the Earth has Changed over Time
2) Use the map below to see where the three different types of plate boundaries are found
throughout the world.\
3) First, find the KEY in the green box located in the lower right-hand corner of the map. Then, roll your
mouse over each boundary name in the KEY to see its location.
4) For the next activity below: Click, Complete, Raise your hand to get your score checked, and record
your score out of
____________________/22 points _________________ Miss Golden’s Initials
Plates & Boundaries Challenge
See how many of the tectonic plates and boundaries you can identify.
Slip, Slide, & Collide
Convergent Boundaries — __________________ _________
At ______________________ boundaries, tectonic plates collide with each other. The events that occur
at these boundaries are linked to the types of plates —__________________ or
_______________________— that are interacting.
Subduction Zones and Volcanoes
At some convergent boundaries, an ___________________ plate collides with a
___________________ plate. Oceanic crust tends to be denser and thinner than continental crust, so
the ______________________ oceanic crust gets ___________________ and pulled
______________, or ________________________, beneath the ____________________ and
________________________________ continental crust. This forms what is called
a ________________________ _________________. As the oceanic crust sinks, a deep
_____________________ ___________________, or _____________________, is formed at the
_____________________ of the continent. The crust continues to be ___________________ deeper
into the earth, where ______________________________ ______________________ and pressure
cause trapped water and other gasses to be released from it. This, in turn, makes the base of the crust
_____________________, forming __________________________.
The magma formed at a subduction zone _________________________ up ________________ the
earth's surface and builds up in magma chambers, where it feeds and
creates ______________________ on the _______________________ ______________. When
this magma finds its way to the surface through a ___________________ in the crust, the
______________ _____________________, expelling lava and ash. An example of this is the band of
active volcanoes that encircle the ____________ ________________ often referred to as the
___________________ ______ _____________.
A subduction zone is also generated when two
Illustration depicting how island arcs are formed.
__________________ _____________
___________ — the ________________ plate is forced ______________ the __________________
one — and it leads to the formation of ________________ of volcanic islands known as
_________________ _________. Examples include the Mariana Islands in the western Pacific
Ocean and the Aleutian Islands, off the coast of Alaska.
Since the collision and subduction of plates is not a smooth process, large, powerful
___________________ are another phenomenon that result from this type of interaction.
_______________________ generated in a ______________________________ zone can also give
rise to _________________________. A tsunami is a huge ocean wave caused by a sudden shift on
the ocean floor, such as an undersea earthquake. If the wave reaches land, it can cause incredible
destruction, like the Asian Tsunami, which killed more than 200,000 people in 11 countries across the
Indian Ocean region in December 2004.
Collision Zones and Mountains
What happens when two continental plates collide? Because the rock making up continental plates is
generally _________________________ and ________________ ______________ than oceanic rock,
it is too light to get pulled under the earth and ______________ into magma. Instead, a collision
between two continental plates __________________ and _________________ the ________ at the
boundary, ______________ _______ ____________ and leading to the formation of
_______________ and mountain ______________________.
An example of this mountain-building process is the _______________________ range in southern
Asia. Containing the highest mountain peaks in the world and traversing the modern-day countries of
India, Pakistan, China (Tibet), Bhutan, and Nepal, the Himalayas were __________________ by the
______________________ of the ______________ and _________________ _____________. This
process began after the breakup of Pangaea, when India became an island continent and began
traveling northward toward Asia. The island of India slammed into Asia about 40 to 50 million years ago
near modern-day Tibet, crushing and folding the plates to form the Himalayan mountain range. Its best
known peaks, Mount Everest and K2, are among several that measure over 8,000 meters (26,000 feet)
high at their summits. Since the Indian Plate is continuing in its northward movement into Asia, the
Himalayas continue to grow higher each year by small amounts (5 to 20 mm or 1 inch per year).
Slip, Slide, & Collide
Divergent Boundaries — ____________________ ___________
At divergent boundaries, tectonic plates are moving away from each other. But if these huge masses of
crust are moving apart, what happens in the space left between them?
_______________________Spreading
Divergent boundaries in the middle of the ocean contribute to ______________ _____________.
As plates made of oceanic crust pull apart, a _____________ in the ________________ _________
appears. ______________________ then oozes up from the mantle to fill in the space between the
plates, forming a raised ridge called a ___________ __________ ____________. The magma also
spreads outward, ______________ ___________________ ___________________ and new oceanic
crust.
Rifts
When two continental plates ____________, a valleylike ___________ develops. This ___________ is
a ____________ ________________ where the plates are ____________ apart. As the crust widens
and thins, valleys form in and around the area, as do volcanoes, which may become increasingly active.
Early in the rift formation, ________________ and ____________ flow into the low _________ and
long, narrow ______________ can be created. Eventually, the widening crust along the boundary may
become ________________ enough that a piece of the continent breaks off, forming a new tectonic
plate. At this point, water from the ocean will rush in, forming a new ____________ or _____________
____________ in the rift zone.
Transform Boundaries — Grinding Plates
At transform boundaries, tectonic plates are not moving directly toward or directly away from each
other. Instead, two tectonic plates _______________ ____________ each other in a
_____________direction. This kind of boundary results in a ____________________ — a crack or
fracture in the earth's crust that is associated with this movement.
Faults and Earthquakes
Transform boundaries and the resulting faults produce many earthquakes because edges of tectonic
plates are jagged rather than smooth. As the plates grind past each other, the jagged edges strike each
other, catch, and stick, _______________ the plates in place for a time. Because the plates are locked
together without moving, a lot of _______________ _________________ up at the fault line. This
stress is __________________ in quick _________________ when the plates suddenly slip into new
positions. The sudden movement is what we feel as the shaking and trembling of
an ____________________.
The motion of the plates at a transform boundary has given this type of fault another name — a
___________ ____________ ____________. The best-studied strike-slip fault is the ________
____________ ________________in California. It is located at the boundary between the Pacific and
North American plates and runs roughly 800 miles (1,300 km) through Northern and Southern
California. As the two plates grind past each other — the Pacific Plate moving northwest and the North
American Plate moving southeast — the motion produces numerous earthquakes along the fault. While
many are small and cause only minor trembling, the San Andreas Fault has also been the site of major
events: the 1857 Fort Tejon earthquake, the 1906 San Francisco earthquake and fire, and the 1989
Loma Prieta earthquake. Many scientists believe that the San Andreas Fault is due to unleash another
large earthquake — a "big one" — in the coming decades.
Plate Interactions Challenge
See if you can figure out the plate movements and geologic events
occurring at real-world locations.
________________________/ 10 Get Checked with Miss Golden
Test Skills ________________________/30 Get Checked with Miss Golden