Environmental Science PowerPoint Lecture

Principles of EnvironmentalScience - Inquiry and Applications,

2nd Editionby 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

http://encarta.msn.com/encnet/refpages/RefMedia

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, 1949. Hawaii Volcanoes National Park, Island of Hawaii

Mauna Loa 1950. 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. 1992. 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

http://encarta.msn.com/encnet/refpages/RefMedia.aspx?refid=461511862&artrefid=761554623&sec=-1&pn=1

http://www.pmel.noaa.gov/vents/geology/MOR.html

http://www.pbs.org/wnet/savageearth/hellscrust/html/sidebar2.html

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 tectonicsWeathering 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 massMinerals have a crystalline, repeating arrangements of atoms, and a specific chemical composition Examples of minerals: quartz (SiO2)

diamond (C)rock salt

(NaCl)

quartz

feldspar

hornblende

mica

Minerals

quartz

feldspar mica

GRANITE

IgneousRock

Rock Types

Rock cycle includes rock

creation, destruction,

metamorphism

granite

schist limestone

marble

shale

slate

sedimentary

igneous

metamorphic

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: