Notes Chapter 3 Earth’s Structure and Materials
Lesson 1: Earth’s Interior
A.
How do geologists study the Earth’s Interior?
1) Direct evidence from ________ _____________.
a. Rocks brought up from ____________.
b. Rocks that blast out from _________________.
2) Indirect evidence from _____________ _____________.
a. _______________________produce seismic waves.
b. The _______________and__________of the seismic waves reveal changes in Earth’s
interior.
B.
What is it like inside the Earth?
1. The _________________ inside the Earth, the ________________ the _______________.
(More rock pressing down.)
2. The deeper down inside the Earth, the _________________ the _____________________.
C.
3 Layers of the Earth’s interior:
1. Crust: ____________________________
a. includes: dry land and ocean floor
1) __________ ___________: _____________- dark, fine-grained rock.
2) ____________________ ___________: composition varies, most like ____________a light colored rock with coarse grains.
b. Main elements are ________________ and ________________.
c. Usually between 5 and 40 kilometers thick.
*thickest under high mountains
2. Mantle:
a. Very hot, but solid rock.
b. Composed of magnesium and iron.
c. 3 layers of mantle:
1. Lithosphere: includes ________ and _________ ____________. Made of same types
of rock as crust.
2. Asthensosphere: less ____________, hotter than lithosphere.
3. Mesophere: ___________ _______________ so rock becomes more rigid.
3. Core:
a. Made mostly of ____________________________.
b. Divided into 2 parts:
1. outer core: ________________, ___________
2. inner core: __________, _____________ ________ ____________. Extreme pressure
pushes the atoms of the iron and nickel together.
Lesson 2: Convection in the Mantle
A. Heat is constantly being transferred inside the Earth.
B. 3 types of heat transfer:
1. Conduction: Heat transfer between two materials that are touching.
2. Convection: Heat transfer by the movement of fluids.
3. Radiation: Heat transfer through rays like light.
C. How does convection occur in the Earth’s mantle?
1. Heating and cooling of a fluid, ______________________________________, and the _________
___________________________combine to set convection currents in motion.
2. ______________________________________________________ cause convection currents in
the mantle.
a. Mantle rock closest to the core is heated, becomes _______ __________ and slowly flows
toward the top.
b. Once the mantle rock reaches the top of the mantle, the rock ___________, becomes
__________ ______________ and sinks back towards the core.
Lesson 3 Classifying Rocks
Rocks are classified according to:
1. Mineral composition: most rocks are made up of a ___________ of _________________.
a. Rock-forming minerals are the ______ minerals that ______ ___ most of the Earth’s
_______.
2. The color of the rock can tell you what it is made of.
a. Rocks with _________ of _________in them are usually __________ colored.
b. Rocks that have a _______ ___________ content are usually _________________.
3. Texture: look and feel of the rock’s surface.
a. Geologist describe texture based on the size, shape and pattern of the grains.
1. Size:
a) Fine: grains can only be seen with ____________________.
b) Coarse: grains are ________ enough to _______________________________.
2. Shape:
a) Conglomerate: ____________ grains.
b) Breccia: _____________ grains
3. Pattern:
a) Nonbanded: no ________________ ___________________.
b) Banded: ________ ________________ that can be flat, swirled or colored.
4. Origin: way the rock formed
a. igneous rocks: form from __________________________
b. sedimentary rocks: form from _______ ___________ or plant and animal remains
c. metamorphic rocks: form from rocks that are placed under ________ or ______________
or subjected to chemical reactions. (Usually form deep under ground).
Lesson 4: Igneous and Metamorphic Rocks
1. Igneous Rock: Any rock that forms from magma or lava.
a.
b.
c.
d.
e.
f.
g.
2.
Extrusive rock is igneous rock formed from ________ that erupted ____________
_____________________.
Example:______________________
Intrusive rock is igneous rock that formed when ___________ hardened __________
_____ _________ _____________. Example: ____________________
Igneous rocks are classified according to their origin, texture, and mineral composition.
Origin: Intrusive/Extrusive
Texture: fine/coarse grained, porphyritic, etc…
Mineral Composition: silica content
Lava that is low in silica usually forms dark-colored rocks like basalt
Magma that is high in silica usually forms light-colored rocks like granite.
Uses of igneous rock includes:
1) Granite for __________________________
2) Basalt for _________________ or crushed for landscaping and roads
Metamorphic Rock: formed from another rock that has been exposed to heat or pressure.
*Metamorphic comes from the Greek word meta that mean “______________” and
morphosis that means “___________”
a. HEAT AND PRESSURE deep beneath the Earth’s surface can change ANY rock into
metamorphic rock.
b. Forces can push rock back toward the heat of the mantle and change rock to
metamorphic rock.
c. Geologists classify metamorphic rocks by the arrangement of the grains that make up
the rocks.
1) Grains arranged in ___________ ________ or ___________are said to be
______________.
2) Some metamorphic rocks are ________________and the grains are
__________________ ___________________.
d. Uses of metamorphic rocks:
1) Marble: used for _________________________
2) Slate: used for ______________________________________.
Lesson 5: Sedimentary Rock: form from particles (sediments) deposited by water and wind.
a. Sediment is small, solid pieces of material that come from ______________________
__________________________.
b. Sediment undergoes the following process that will change it into sedimentary rock.
1) Weathering: _______________________ due to freezing and thawing or plant roots
2) Erosion: wind or water ______________________ the broken pieces of rock
3) Deposition: sediment (small pieces of rock) ____________ of the water or wind.
4) Compaction: sediments are ____________________________.
5) Cementation: sediments are __________________________.
c. There are three major groups of sedimentary rocks: Clastic, Organic, and Chemical
rocks.
1. Clastic: Rock fragments squeezed together.
2. Organic: Plant and animal remains.
3. Chemical: Minerals dissolved in a solution crystallize.
d.
Uses of Sedimentary Rocks
1. Flint used to make _____________________
2. Sandstone and limestone used as ________________________.
Lesson 6: Rock Cycle:
1.
Rock cycle is a __________ of _______________ that occur on the Earth’s surface and in the
crust and mantle that slowly ____________ _________ from ____ ________ to
_______________.
2. There are ___________ pathways through the rock cycle.
3.
The rock cycle is the result of both _____________ and _________________ events:
a. Surface events: weathering, erosion, and deposition of sediment on the Earth’s surface
form _________________ ____________.
b. Subsurface events:
1) colliding plates form mountains
2) colliding plates can produce volcanoes that form new ______________ __________.
3) colliding plates produce heat and pressure which can change the rock at the point of
contact into ____________________ _____________.