Document #_________
Heading:
Geology
NOTES #6
Subject: III. Rocks and Minerals
Main Ideas
C. Classifying (grouping) Rocks
1. Origin
2. Texture
a. Grains
Details

Where and how the rock is formed

Size, shape, and pattern of rock’s grains

Particles of minerals or other rocks.
i.
Grain Size

Fine, Medium, & Coarse
ii.
Grain Shape

Jagged or Rounded
iii.
Grain Pattern

Wavy, Flat Layers, Random (no pattern)
iv.
No Visible Grains

Smooth and Shiny
3. 3 Types of Rocks
a. Igneous Rocks
b. Sedimentary Rocks
c. Metamorphic Rocks
- Forms from the cooling of molten rock (magma and/or lava).
- Forms when particles of minerals and/or rocks, animals, or plants are
cemented together.
- Formed when a rock is changed by heat and pressure deep inside the
earth.
Summary: Rocks are grouped into __________ different categories: ______________, __________________,
and ____________________. Scientists group rocks by _____________ and ____________________, which is
determined by grain ________________, _________________, and ___________________.
Subject: III. Rocks and Minerals
Main Ideas
Details
D. Classification of Igneous
Rocks
•
•
•
Classified according to their _Origin__ (where they formed),
_Texture_ (how they feel in terms of grain size, shape, and
pattern),
Mineral _Composition_ (the minerals that make up the rock).
1. Origin (where they
form)
a. Extrusive Rocks
-
forms from _lava__ that has exited the volcano or earth’s crust
Example: Basalt – most common extrusive, forms most of
__oceanic__ crust beneath ocean floor.
b. Intrusive Rocks
-
forms when _magma__ cools and hardens inside the Earth.
Example: Granite – most abundant intrusive, forms most of
continental crust.
2. Texture
- depends on size of crystals/grains
- The faster the lava cools, the smaller the crystals.
- The slower the magma cools, the larger the crystals.
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Summary: __________________ rocks are formed from ______________ or ______________. ____________
Igneous rocks are formed from magma and have _______________ crystals/grains. _____________________
Igneous rocks are formed from lava and have ___________________ or no crystals/grains.
Subject: III. Rocks and Minerals
Main Ideas
E. From Sediment to Rock.
Sedimentary Rocks
Details


Sediment – small, solid pieces of material that come from
rocks or living things
It is carried by water, wind, and ice, gravity.
1. The 5 Processes
that make Sedimentary
Rock
a. Weathering
– process that breaks rock into smaller pieces by wind, water, heat,
ice, and gravity.
b. Erosion
– wind, water, ice, or gravity moves sediment from one place to
another
c. Deposition
– sediment settles out of the water, wind, or ice carrying it.
d. Compaction
e. Cementation
F. The 3 Types of Sedimentary Rocks
1. Clastic Rocks
– process that presses sediment together
– process in which dissolved minerals solidify and glue particles of
sediment together.

Sed. rocks classified according to type of sediments that make
up the rock.
-forms when inorganic sediment is squeezed together.
-Examples: Shale, Sandstone, Conglomerate, Breccia
2. Organic Rocks
- forms where the remains of plants and animals are deposited in
thick layers.
-”Organic” refers to substances that once were part of living things.
- Examples: Coal, Limestone
3. Chemical Rocks
– form when minerals that are dissolved in a liquid crystallize
(harden).
Example: Halite
Summary: ____________________ Rocks are formed from ________________ by ______________________,
_____________________, ______________________, ____________________, and ____________________.
Sedimentary Rocks are classified according to the types of _______________________ that make up the rock.
There are ____ types of Sedimentary Rocks: _______________, ________________, and _________________.