Environmental Science PowerPoint Lecture Principles of Environmental Science - Inquiry and Applications, 2nd Edition by William and Mary Ann Cunningham

Chapter 11 familiarize you with: Understand some basic geologic principles, including how plate-tectonic movements affect conditions for life on earth Explain how the three major rock types form and how the rock cycle works Summarize economic mineralogy, strategic minerals Discuss environmental effects of mining and mineral processing Recognize geologic hazards: earthquakes, volcanoes, floods, and erosions

Key Terms – Chapter 11 Barrier islands Core Crust Earthquakes Flood Floodplains Heap-leach extraction Igneous rocks Landslides Magma Mantle Metamorphic rocks Midocean ridges Mineral Rock Rock cycle Sedimentary rocks Sedimentation Smelting Strategic metals & minerals Tectonic plates Volcanoes Weathering

Chapter 11 - Topics A Dynamic Planet Minerals and Rocks Economic Geology and Mineralogy Environmental Effects of Resource Extraction Conserving Geologic Resources Geologic Hazards

Part 1: A Dynamic Planet Oceanic crust Young – 200 million years old Mainly basaltic Inner core - Mostly Fe Continental crust Old – 3.8 billion years Mainly granitic

Tectonic Plates

that 200 million years ago there was a single supercontinent called Pangaea that combined all the world's continents in a single landmass?

70 million years ago

Volcanoes and Plate Tectonics

Plate Movements ~ 8 major tectonic plates on Earth Plates move slowly – 0.8 to 12 inches (8 to 30 cm) a year Movement caused major changes in position of continents over the last few hundred million years Most scientists think convection currents in earth’s mantle cause plate movement

Mount Everest, Himalayas (highest mountain in world) – Indian plate pressed against Eurasian continental plate, lots earthquakes

Eruption Mauna Loa, Hawaii Volcanoes National Park, Island of Hawaii Mauna Loa Lava River. Hawaii

Lava flowing into sea, Hawaii – island building and growth

Hawaii, sugar cane, volcanic soils receiving new nutrients with eruptions (why people live on volcanoes) St. John

Iceland geology Eruption at the Hekla volcano, South Iceland, 2000 Photo taken 29/2 by Sigurjón H. Sindrason Lots of Hot Springs – generate electricity, bath, swimming pools, heat houses (sulfur smell in water)

E.A. Keller Environmental Geology

The San Andreas Fault emerges from Pacific Ocean and runs through California about 600 mi from Point Arena to the Imperial Valley - boundary between North American & Pacific tectonic plates

Mid-ocean ridges Hydrothermal vents or ‘black smokers’ Tube worms High in sulfur, copper, zinc, gold, iron 700 F

The Rock Cycle – driven by plate tectonics Weathering breaks down surface rock, erosion deposits in sedimentary formations Old seafloor, sediment deposits melt in subduction zone or recrystallize deep into igneous rocks Magma rises - volcano Tectonic movement create pressure, heat & metamorphism –form sedimentary, igneous rocks

Rocks are assemblages of minerals held in a solid mass Minerals have a crystalline, repeating arrangements of atoms, and a specific chemical composition Examples of minerals: quartz (SiO 2 ) diamond (C) rock salt (NaCl)

quartz feldspar hornblende mica Minerals

quartz feldspar mica GRANITE Igneou s Rock

Rock Types Rock cycle includes rock creation, destruction, metamorphism

granite schistlimestone marble shale slate sedimentary igneous metamorph ic ROCKS 50% calcium carbonates Calcium carbonate recrystallized as calcite

sandstone mudstone shale Some Sedimentary Rocks

Rainbow Bridge, Utah

Weathering and Sedimentation Mechanical weathering - physical breakup, no change chemical composition (ex. Water) Chemical weathering – selective removal, alteration of specific components (oxidation, hydrolysis) Sedimentation – deposition of loosened rock

The chemical and physical breakdown of rocks into their component minerals or elements Weathering: