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Plate Tectonics
Layers of earth, continental drift, sea-floor spreading, & plate tectonics
23
Science
6th Grade
09/26/2008

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Cards

Term

Geologist

Definition

Scientists who study the Earth

Term
Crust
Definition
The thin (5-40 km), rocky outermost layer of Earth's surface
Term
Seismic Waves
Definition
Wave of energy generated at the focus of an earthquake that travels through earth.
Term
Mantle
Definition

Lies below the crust and is the thickest (3,000km) layer of Earth's interior.

Term
Asthenosphere
Definition

The plastic-like layer found in the upper mantle, and it lies 100km to 250km below the surface.  Also, plates of the lithosphere float on top of this layer.

Term
Lithosphere
Definition
The brittle and rigid, outer layer of Earth formed of the crust and upper part of the mantle.
Term
Convection
Definition
The movement of thermal energy (heat) in a fluid. Convection currents inside Earth help drive plate motion.
Term
Continental Drift
Definition

The idea that continents are moving very slow, parallel to Earth's surface.  The hypothesis was supported by the find of rock structures and fossils.

 

-is an idea that suggested the continents fit together like a puzzle.

Term
Pangaea
Definition

One big landmass, ancient supercontinent that began breaking up about 200 million year ago. 

 

Pangaea means "all land".

Term

Evidence for Continental Drift

Definition

1. Shape of continents

2. fossils

3. Mountain ranges and rock types

4. Climate data

 

Be prepared to write a paragraph about this!

Term

Mid-Ocean Ridge

Definition

Long mountain range in the middle of the seafloor where new oceanic crust forms, and has the youngest rocks.

Term
Seafloor Movement
Definition

Lava flows through the cracks along the mid-ocean ridge,cools, and forms new seafloor.

Term
Seafloor Spreading
Definition

Process by which new seafloor is made (molten material beneath Earth's crust rises to the surface)and then moves sideways away from mid-ocean ridges (176)

 

-Explains how new rocks are formed in the ocean.

Term
Lithospheric Plates
Definition
Large brittle pieces of Earth's outer shell.
Term
Divergent Plate Boundaries
Definition
Boundary where two lithospheric plates are moving apart.
Term
Continental rifting
Definition
Occurs when two continental plates are being pulled apart.
Term

Convergent Plate Boundaries

Definition
Form when two lithospheric plates move toward each other.
Term
Transform Plate Boundaries
Definition
Exists when two plates slide horizontally past one another.  An example of this is San Andreas Fault in California.
Term
Slabs
Definition
Cooler,denser lithospheric plates that sink down into the mantle.
Term
Slab Pull
Definition
Gravity pulls on the slab of rock being subducted which then pulls the rest of the plate along with it. Important in controlling the movement of lithospheric plates. (page 190)
Term
Inner Core
Definition
Innermost layer of the Earth. Extremly high pressure cause the metal to be in the solid state.
Term
Outer Core
Definition
Located between the mantle and the inner core. Made of molten (liquid) metal. Has convection currents.
Term
Plate Tectonic
Definition
States that the plates of the lithosphere are in constant, slow motion, driven by convection currents and slab pull.
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