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: