1. IGNEOUS ROCKS Igneous – derived from the Latin word ignis, meaning Fire.

2. IGNEOUS ROCKS
Lava is molten rock found at or near Earth’s surface. Magma is molten rock found beneath Earth’s surface. Igneous Rocks form from both lava and magma.

3. 3 Ways Magma Can Form
Pressure – The high pressure inside Earth causes Hot rocks and minerals to remain solid. When those hot rocks rise and the pressure lowers, the minerals melt.
Temperature – High temperatures melt minerals. Each mineral has a different melting point – so some minerals melt when others remain solid.
Composition – If fluids, such as water, combine with the rock, the composition of the rock changes which lowers the melting point enough for it to melt and lower temperatures.

4. Igneous Rock
Forms when hot, liquid rock or magma, cools and solidifies
Found near volcanic activity
Liquid magma is a mixture of many minerals

5. Intrusive & Extrusive
Those igneous rocks that form from magma are referred to as INTRUSIVE. INTRUSIVE = Inside Those igneous rocks that form from lava are referred to as EXTRUSIVE. EXTRUSIVE = Outside

6. Lava
Extrusive
Lava
Lava
Intrusive
Magma

7. TEXTURE of Igneous Rocks
Determined by how fast the magma cools
Smooth grained rocks are formed by magma that cools quickly (Extrusive)
Coarse grained rocks are formed when magma cools slowly (Intrusive)

9. IGNEOUS ROCK FORMATIONS
Intrusive
Extrusive
Form Below Earth’s surface and inside the Earth
Intrusive rocks have a coarse grained texture because ?
Forms on the Earth’s surface
Extrusive rocks have a smooth texture because ?

10. COMPOSTITION of Igneous Rocks
Light colored rocks are less dense and rich in Quartz Felsic
(aluminum, potassium, silicon and sodium)
Dark colored rocks are more dense and contain Plant Nutrients.
(calcium, iron, magnesium)
Mafic

11. Mafic, fine grained, extrusive
Igneous Rock QUESTION
Obsidian is a dark-colored volcanic glass that forms from the very rapid cooling of molten rock material. It cools so rapidly that crystals do not form.
Is this rock Felsic or Mafic?
Is it fine-grained or coarse-grained?
Is this rock Intrusive or Extrusive?
Mafic, fine grained, extrusive

12. Andesite – Fine-grained, extrusive Felsic igneous rock

13. Basalt is also an abundant rock on the Moon
Basalt is also an abundant rock on the Moon. Much of the Moon's surface is underlain by basaltic lava flows and flood basalts. These areas of the Moon are known as "lunar maria."
Basalt – Fine-grained, extrusive Mafic

14. Diorite – Coarse-grained, intrusive. Mixture of Mafic and Felsic

15. Gabbro – Coarse-Grained, intrusive, Mafic igneous rock

16. Pumice – Extremely Fine-Grained, Extrusive Felsic Igneous Rock
Form during explosive volcanic eruptions from the cooling of the frothy magma

17. Forms when some volcanoes erupt, a rush of gas blows out of the vent
Forms when some volcanoes erupt, a rush of gas blows out of the vent. This gas was once dissolved in the magma below. The gas often blows out small bodies of magma that solidify as they fly through the air.
Scoria – Extremely fine-grained, Extrusive Mafic Igneous Rock