Earth on the Move Earth Structure & Plate Tectonics Notes.

Earth on the Move

Earth Structure & Plate Tectonics Notes

Baker 7th grade science 2003-2004

Core

i) Deep within the Earth is the core

ii) The core is made mostly of nickel & iron

iii) Twice as dense as the mantle.

Main source of heat that triggers the convection currents


The core is made of two layers

(1) Outer core: molten (liquid) nickel and iron

Inner core: solid nickel and iron– Densest layer of the

earth


Mantle

Full of very hot rock that flows

Where magma is located

Thickest layer/ 60-75%

Most of the earth’s mass 80%


Mantle

3 Parts of the Mantle– Mesosphere– Asthenosphere– Lithosphere


Mesosphere

Strong lower part of mantle

Between outer core and asthenosphere


Asthenosphere

Hot, weak zone directly under the lithosphere

Flows at a very slow rate

Has convection currents that moves tectonic plates


Lithoshpere

Thin, uppermost part of the mantle; cooler & less rigid

Floats on the athenosphere, and slides around very slowly.

(iii) The upper part of the lithosphere melts rocks, forming a substance called magma.


In Mantle

Convection Current: process by which hot fluid or rock rises to the surface and cool rock sinks.


Crust outermost thinnest

layer of the Earth. 2 types of crust

– Oceanic – made of basalt – more dense

– Continental – made of granite – less dense


Lithosphere Thinnest physical

layer Floats on the

asthenosphere


Seismic Waves The speed tells

us about the earth’s interior– How thick– How dense– Solid or liquid


Earth, Inside & Out

3 Compositional Layers

1. Crust 2. Mantle3. Core

5 Physical Layers 1. Lithosphere 2. Asthenosphere3. Mesosphere4. Outer Core5. Inner Core


Inner Core

Composition– iron + nickel

Thickness– 1,230 km

State of Matter– solid


Outer Core

Composition– iron + nickel


State of Matter– liquid


Mantle

Composition– Silicon,

magnesium, aluminum


State of Matter– Plasma


Crust

Composition– Oxygen, silicon,

aluminum Thickness

– 5-100 km State of Matter

– solid

Earth on the Move Earth Structure & Plate Tectonics Notes.

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