Igneous RocksIgneous Rocks Igneous RocksIgneous RocksChapters 3 & 4Chapters 3 & 4Chapters 3 & 4Chapters 3 & 4

Arcadia Nat’l Park, Maine

How do Igneous Rocks form?

What is Magma?

What is Lava?

How do they form?

• What are the two categories of igneous rocks?What are the two categories of igneous rocks?

• How does each type form?How does each type form?

How are plutons & volcanoes related?

How Hot Is Lava?

• How long does it take lava to cool?

Where Does Magma Originate?

Where are Magma Chamber located?Where are Magma Chamber located?

How does pressure affect the melting point of a rock?

What is the Geothermal gradient?

How does water affect rocks at depth?

TEXTURES of Igneous Rocks

• What is Texture?

• What does a rock’s grain size indicate?

What is Aphanitic texture and what does it indicate?

• What is Glassy texture & what does it indicate?

• What is Vesicular texture & what does it indicate?

a b

TEXTURES of Igneous Rocks (cont.)

What is Phaneritic texture & what does it indicate?

TEXTURES of Igneous Rocks (cont.)

• What is Porphyritic texture & what does it indicate?

TEXTURES of Igneous Rocks (cont.)

• What is Pyroclastic (fragmental) texture & what does it indicate?

TEXTURES of Igneous Rocks (cont.)

What is the most abundant constituent of magma?What is the most abundant constituent of magma?

• What characteristics do Felsic magmas have?

• What characteristics do Intermediate magmas have?

• What characteristics do Mafic magmas have?

• What characteristics do Ultramafic magmas have?

Magma CompositionMagma Composition

Composition of Igneous Rocks• What controls the type of rock that forms?

What are the 4 Magma Modification Processes?

What is Crystal settling?

What is Assimilation?

How does it affect a magma’s composition?

• What is Magma mixing & how does it affect a magma’s composition?

Who discovered Bowen’s Reaction Series?

What is Bowen’s Reaction Series?

How are Igneous Rocks Classified?

A B

• Felsic are _______ colored b/c they’re composed of orthoclase, Na-plagioclase, & quartz.

Rhyolite (A) Granite (B) [most common intrusive rock]

Pegmatites are __________________ (grains >1 cm in diameter) & are mineralogically similar to ______.

• These mineral grains crystallized from ______________

____________________________________________.

Intermediate contain _________ amts of _________ colored ferromagnesian silicates, & _________ colored feldspar.

Andesite (A) Diorite (B)[erupts from island arcs]

A B

Mafic rocks are ______colored b/c they’re largely composed of ______________________________________.

Basalt (A) Gabbro (B)

A

B

Ultramafic are _____ colored b/c they are comp. of ________________________________ silicates.

What are Peridotites composed of olivine?

Where are Peridotites formed?

What rock type has a similar composition?

Why can volcanic glass be different colors?

What are vesicles & how are they formed?

What is Volcanic Glass composed of?

PumiceObsidian

What are Tuffs?

What are the Magma Types at Convergent Margins?

How are these magmas

formed?

How do magmas move?

What is Magma type at Divergent Margins & Hot Spots?