Todays Objective What makes Igneous Rocks special Do

Today’s Objective: What makes Igneous Rocks special? Do Now: THINK What are sedimentary and how are they classified?

Environments of Formation ESRT pg 6

Environments of Formation – rocks that form when magma hardens beneath Earth’s surface. ** The slower MAGMA cools the larger the crystals *** Granite

– When lava hardens on the Earth’s surface. -Lava cools quickly, resulting in - Smaller crystals. - Vesicular texture (holes). - No Crystals at all (glassy).

Textures of Igneous Rocks

Textures of Igneous Rocks Intrusive – Slow cooling results in the formation of large crystals. Extrusive – Rapid cooling of magma or lava results in rocks with small, interconnected mineral grains.

Ex: Obsidian Extrusive – Glassy texture results from cooling that is so fast that minerals do not have a chance to crystallize. Ex: Pumice - Vesicles (holes, pores, or cavities) are the result of gas bubbles, which often occurs during volcanic eruptions.

Characteristics of Igneous Rocks

Composition of Igneous Rocks – a lighter color – a darker color - a lower density - a higher density - rich in Silicon (Si) and Aluminum (Al) - rich in Iron (Fe) and Magnesium (Mg)

Mineral Composition of Igneous Rocks Rhyolite is made up of: - Potassium feldspar - Quartz - Plagioclase feldspar - Biotite (mica) - Amphibole

Mineral Composition of Igneous Rocks What is Gabbro made of? - Plagioclase feldspar - Biotite (mica) -Pyroxene - Olivine - Amphibole

Using your knowledge of earth science, your earth science reference tables and your class notes contrast Basalt and Granite in terms of how each forms, the texture of each, the color and the composition in your notebook. Basalt Formation Texture Color Composition Granite