Intrusive: Rocks formed deep inside Earth Formed from magma Cool very slowly Have large crystals

Extrusive: Rocks formed on or near Earth’s surface Formed from lava Cool very rapidly Have small or no crystals

Felsic: Light or red in color Usually Lower

density High content of

aluminum

Mafic: Dark or green in color Usually Higher

Density High content of iron

or magnesium

COMPOSITION Felsic Intermediate Mafic

Lighter---------------------------Color----------------------------Darker Lower---------------------------Density--------------------------Higher

Intrusive Course

Grained Granite Diorite Gabbro

Extr

usi

ve Fine

Grained Rhyolite Andesite Basalt

Vesicular Pumice Scoria

Glassy Obsidian

INTRUSIVE

EXTRUSIVE

EXTRUSIVE

Intrusive

EXTRUSIVE

Felsic

Felsic

Mafic

Could be Both

• Definition:

– Small, solid pieces of material that come from rocks or living things like leaves, shells, etc.

Clastic Formed from various rock fragments Deposited by water, wind, glaciers Classified by grain size and shape Formed from Cementation or Compaction

Grain Size and Shape

Texture Grain Size Composition Comments Rock Name

Inorganic Land-Derived

Clastic

Pebbles, cobbles, and/or boulders

embedded in sand, silt and/or clay

Mostly quartz, feldspar, and clay

minerals; may contain fragments of

other rocks and minerals

Rounded fragments Conglomerate

Angular fragments Breccia

Sand (0.2 to 0.006 cm) Fine to course grained Sandstone

Silt (0.006 to 0.0004 cm) Very fine grained Siltstone

Clay (less than 0.0004 cm)

Compact, cannot see individual grains Shale

Chemical Formed when minerals dissolved in water crystalize

Think back to salt crystal lab

Crystalline(Chemical)

Fine-grained; crystals from

chemical precipitates and

evaporates

Halite

Softer than a fingernail, will not

react with acid, salt Rock Salt

Gypsum

Softer than a fingernail, will not

react with acid Rock Gypsum

CalciteCarbonate: will react

with acid Limestone

Organic Sedimentary Rock Forms where the remains of plants & animals are

deposited

Bioclastic(Organic)

Fine to course Calcite

Made of shells, will react with

acid Coquina

Fine-grained Carbon

Dark in color; made from plant

remains Coal

Coal

Coquina

The term "metamorphic" means "to change form.“

These rocks have been put under high pressure and temperatures

They are not melted in this process, instead new minerals and physical make up change

There are two types of metamorphic rocks.

Each is classified according to its composition and texture. Foliated Nonfoliated.

FOLIATED metamorphic rocks are those in which the minerals have been flattened and pushed into layers

Examples of foliated rocks are slate, and gneiss.

NON-FOLIATED metamorphic rocks do not display layers. Rather, they are massive structures with no obvious banding.

The mineral grains grow and rearrange, but they don’t form layers.

A good example of non-foliated rock is quartzite or Marble

Metamorphism can occur in different degrees

The crystals can rearrange themselves without being melted

A metamorphic rock can go through metamorphism