Plate Tectonic Vocabulary and Notes
Earthquake: a shaking or movement of Earth’s surface; caused by the release of stored
energy along a fault. Earthquakes occur along plate boundaries.
Fault: A break in rock along which rock slabs have moved. The shifting of Earth’s
tectonic plates can produce a fault, along which earthquakes may occur.
Tectonic plate: One of the slabs that make up Earth’s crust and upper mantle. Some of
Earth’s tectonic plates carry continents.
Plate boundary: A place where the plates that make up Earth’s crust and upper mantle
either move together or move apart or move past one another.
The coastal areas on either side
of the Pacific Ocean make up
The Ring of Fire.
This area consists of many
active subduction zones.
Theory of continental drift: A theory that states that the continents were a single
landmass at one time in the past, and have moved over time to their present positions.
The theory of continental drift was first suggested by Alfred Wegener. *note, this is not
the first time the continents had been together in one landmass.
Pangaea: the name given to the last supercontinent that existed over 250 million years
ago.
Evidence pointing towards the Continental Drift Theory are; the shape of the continents
and how they seem to fit together like puzzle pieces, the finding of fossils of the same
animals but on different continents, the same geological (landmass) features on facing
coastlines of separated continents and lastly, climate similarities found in areas that
were once connected. See examples of this below.
1. Pieces fitting together:
2. Same types of fossils found on
separate continents:
3.Geologic Evidence Similarities „ The age and type
of rocks are similar in the coastal regions: Rock samples taken from
along the coastline of Africa are similar in age and type to the
samples taken from South America. In the picture to the left, the
age and structure of the Appalachians (in the Eastern U.S.) is similar
to mountains in Greenland and Northern Europe, and the
Caledonians of Britain and Norway are very similar (folded mtns.)
and are also similar in age. When we fit Europe and North America
together, we find that The Appalachians and Caledonides form a
single mountain chain.
4. Climate evidence:
Below shows how the continents slowly shifted to present day positions:
Theory of plate tectonics: The theory that Earth’s lithosphere and crust is broken into
enormous slabs, or plates, that are in motion. Scientists use the theory of plate tectonics
to explain how Earth’s continents drift.
Convection currents in the magma drive the movement of plates!
Earth Layers:
Crust: The thin, rocky outer layer of
Earth. The layer we live on. Under
the oceans the crust can be as thin as
10 km (6miles) and where there are
mountains the crust can be as thick as
65 km (40 miles).
Mantle: The layer of the Earth
between the crust and the core. The
mantle is the thickest layer of the
Earth (2,900 km or 1,740 miles)
Lithosphere: The rigid, rocky layer of
Earth found in the lower crust and the
upper most portion of the mantle.
The lithosphere is about 100 km (60
miles).
Asthenosphere: The region of the
mantle just below the lithosphere. It is the upper part of the mantle that is hot, partially
melted, slightly fluid and is able to flow.
Core: The innermost, densest layer of Earth. The core is made up of two parts, the
outer core and the inner core. The outer core is molten and is made up of iron and
some less dense material. The inner core is solid and is mostly iron and possibly some
nickel.
Convection current: The pathway along which energy travels through a fluid or gas.
Heat rises, cools and sinks. This is a continuous cycle. This causes plate movement!
Types of Boundaries:
Convergent boundary: A place where the plates that make up Earth’s crust and upper
mantle collide or come together. Layers of rock may bend or break at a convergent
boundary. Subduction: The process of moving part of the lithosphere down into the
mantle along a convergent boundary.
Divergent boundary: A place where the plates that make up Earth’s crust and upper
mantle move away from one another. Most divergent boundaries are found on the ocean
floor.
Transform-fault boundary: A place where the plates that make up Earth’s crust and
upper mantle move past one another.
This picture shows the 3 types of boundaries again:
A. Makes ridges
And rift valley.
B. Makes trenches
And volcanic
Mountains.
C. Makes trenches
And mountain
Ranges.
D. Can have
Fault Lines
visible on surface. Distorts current landforms.
Sea floor spreading: The process by which new ocean floor is continually being formed
as magma rises to the surface and hardens into rock. Sea-floor spreading occurs as
magma fills the space between separating plates.
Mid-ocean ridge: A chain of mountains on the ocean floor. New ocean floor forms at
the mid- ocean ridge where the sea floor is spreading. Forms at a divergent boundary.
Trench: Very narrow and deep area created when one plate is subducting under
another.
Magma: The hot, molten rock deep inside Earth. Lava: Magma that flows out onto
Earth’s surface from a volcano.
Rifting: The process by which magma rises to fill the gap between two plates that are
moving apart. Rifting in eastern Africa may split the continent into two parts.
Geothermal energy: Energy derived from the heat of Earth’s interior.
Sediment: Earth material, such as soil and rock fragments formed by weathering.
Seismograph: An instrument that records the intensity, duration, and nature of
earthquake waves.
Check this out!!! You asked why are there so many earthquakes around
Japan????