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Igneous Rock Classification. 8 th Grade Earth and Space Science Class Notes. Thursday, 12/6. Warm – Up Explain the difference between an intrusive and an extrusive rock. Write down the HW. Learning Goal – Describe the characteristics of igneous rocks. Agenda Warm-Up Question/Review HW
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Igneous Rock Classification 8th Grade Earth and Space Science Class Notes
Thursday, 12/6 Warm – Up • Explain the difference between an intrusive and an extrusive rock. • Write down the HW. Learning Goal – Describe the characteristics of igneous rocks. Agenda • Warm-Up Question/Review HW • Review procedures for the Igneous Rock Lab • Completethe Igneous Rock Lab • After the lab – work on the Chapter 5 Review Packet, 5.2 Vocabulary, and reviewing your Greek and Latin Roots Homework – Section 5.2 Vocabulary due on Friday, 12/7 Chapter 5 Review Worksheets due on Friday, 12/7 Greek and Latin Roots Quiz #1 on Friday, 12/7 Chapter 5 Quiz (25 pts.) on Monday, 12/10
Friday, 12/7 Warm – Up • Explain the difference between the terms “porphyritic” and “vesicular”. • Write down the HW. Learning Goal – Describe the characteristics of igneous rocks. Agenda • Warm-Up Question/Review HW • Greek and Latin Roots Quiz #1 • Check/correct the Section 5.2 Vocabulary and the Chapter 5 Review Packet • Play the Chapter 5 Review Game/Complete the Igneous Rock Lab Homework– Chapter 5 Quiz (25 pts.) on Monday, 12/10
Formation and Texture • Intrusive – forms under the Earth’s surface • Large grain magma cools slowly and large crystals form • Extrusive - forms on top of the Earth’s surface • Small grain magma cools too quickly and small or no crystals form Intrusive Extrusive
Formation and Texture • Porphyritic – two different crystal sizes • Caused by cooling in different environments • Vesicular – spongy appearance • Caused by gas bubbles Porphyritic texture Vesicular texture
Mineral Content • Basaltic – dark color, low silica content • Granitic – light color, high silica content • Intermediate – in between basaltic and granitic • Ultrabasic – very dark, only iron-rich minerals Ultrabasic Granitic Intermediate Basaltic
Rocks as Resources • Veins – also called “igneous intrusions”; small spaces that contain valuable ores • Pegmatites – veins of very large grained minerals that contain rare elements Gold Vein Beryl Crystal in Pegmatite
Rocks as Resources • Kimberlites – type of peridotite (ultrabasic rock) that contains diamonds