Ch 4 Igneous Rocks printable pdf download

Ch 4 Igneous Rocks

A. Rocks and The Rock Cycle

1. _____________ - group of minerals bound together in some way

2. _______________ - cooling and hardening of hot molten rock

3. ________________ - Hardening and cementing of layers of sediments

4. ___________________ - changed by heat and pressure

5. ____________________ - transformation from one rock type to another

B. Igneous Rocks: The Origin of Magma

1. Processes that form magma

a. Rising __________________ - in crust - temp rises 30

C / km of depth

b. Decreasing ____________________ - pressure release melting

c. Addition of ___________ - wet rock melts at a lower temp than a dry rock

2. Environments of magma formation

a. ___________________________ - plates spread apart - asthenosphere rises,

pressure drops and forms basaltic magma - ocean basins - mid oceanic ridges

b. ___________________ - volcanically active place at the Earth’s surface

directly above a mantle fume - Yellowstone National Park, Hawaii Islands

c. ________________________ - addition of water - subducting plates -

volcanoes of Pacific Northwest, granite cliffs of Yosemite, and Andes Mountains

3. Characteristics of magma

a. Temperature varies from ________ C to ___________ C

b. Chemical composition - silicate magmas- ____ and _____

(1) Basaltic magma - more ______and ______

(2) Granitic magma - more ______, _______, and ______

c. Behavior - when rock melts it expands 10%

Ch 4 Igneous Rocks