Hint: Ignite means to light on fire

Igneous Rocks Rocks made from solidified magma or lava.

Molten Rock – Partially Melted minerals Magma- Molten Rock below the Earth’s Surface Lava – Molten Rock that has reached the Surface

Classification of Igneous Rocks Based on: Texture Color Mineral Composition Density

Texture = Crystal Size The longer the molten Rock takes to cool the larger the crystals Crystals Forming

Texture is used to classify rocks as intrusive or extrusive INTRUSIVE EXTRUSIVE Formed below the surface Made from Magma Cool slowly because they are cooling below the surface where the temps are hotter Large visible crystals – coarse or very coarse texture, because these rocks take longer to cool giving them a chance to form crystals Formed at the surface (exterior of the Earth) Made from lava Cool fast because the lava is exposed to air and water. Fine – very small crystals not visible to the naked eye Glassy and Vesicular texture- absence of crystals (cooled very fast so crystals did not have time to form)

Vesicular Texture Rock has holes in it due to popping gasses. As Lava cooled very fast gases that were escaping left pop marks in the rocks surface

PORPHYRITIC TEXTURE Rock has both small and large crystals Why?? Because the rock had two different cooling stages While the rock was cooling below the surface it was pushed up to the surface where it could cool faster

INTRUSIVE OR EXTRUSIVE?? Texture ? Coarse /Intrusive Glassy / Extrusive

Color may be used to classify igneous rocks as Mafic or Felsic MAFIC FELSIC Dark Color High in Magnesium and Iron High Density Light Color High in Silica, Aluminum Low Density

Mafic or Felsic??? MAFIC FELSIC

Obsidian’s Exception Obsidian is considered a FELSIC rock but it is black and dark in color Since obsidian cooled very very fast all of the dark minerals didn’t have the time to separate from the lighter minerals ( so even though there is a smaller percentage of the dark minerals they over power the lighter ones and make the rock look mafic BUT IT IS FELSIC!!! *** Like if you drop one dark chocolate chip into melted white chocolate

Bowen’s Reaction Series – describes the formation of igneous rocks from different starting temps and magma composition

Bowen Reaction series

Let’s Try Using the HANDY DANDY REFERENCE TABLES!!!! ESRT

The basaltic bedrock of the oceanic crust is classified as (1) felsic, with a density of 2.7 g/cm3 (2) felsic, with a density of 3.0 g/cm3 (3) mafic, with a density of 2.7 g/cm3 (4) mafic, with a density of 3.0 g/cm3

The granite bedrock formed when (1) sediments were buried (2) a volcano erupted (3) magma cooled underground (4) limestone recrystallized

This question may require the use of the Earth Science Reference Tables. Compared to felsic igneous rocks, mafic igneous rocks contain greater amounts of 1. white quartz 2. aluminum 3. pink feldspar 4. ironEarth Science Reference Tables