The Earth presented by Prof. Geller 29 October 2002 HNRS 227 Lecture #18 Chapter 19 The Earth presented by Prof. Geller 29 October 2002

Key Points of Chapter 19 Minerals Rocks The Rock Cycle Igneous, Sedimentary, Metamorphic The Rock Cycle Earth’s Interior Crust, Mantle, Outer Core, Inner Core Plate Tectonics

Telling Rocks Apart How geologists tell apart different minerals and rocks color, luster, texture hardness test scratching one against another diamond is hardest acid test using weak hydrochloric acid to streak test form a streak across a ceramic tile

Minerals (see Table 19.1) Characteristics naturally occurring inorganic definite crystalline structure The natural resources of industry

“Rocks formed from hot molten mass of melted rock material” Igneous Rocks “Rocks formed from hot molten mass of melted rock material” See Figure 19.11 in textbook

Sedimentary Rocks “Rocks formed from particles or dissolved materials from previously existing rocks.” See Table 19.2 in textbook

Metamorphic Rocks “Previously existing rocks that have been changed by heat, pressure, or hot solutions into a distinctly different rock.” See Figure 19.13 in textbook

The Rock Cycle

Earth’s Interior and How We Know It

Earthquakes Galore

Earth’s Inside Story

Crustal Rumblings

Plate Tectonics “The theory that the Earth’s crust is made of rigid plates that float on the asthenosphere.” Consider the scientific evidence for plate tectonics and what forced scientists to accept the theory as fact

Fossils across an ocean

Boundaries Galore

Plates are smashing