Lecture 1- Geologic Processes

Geology  Study of the processes occurring on the earth’s surface and in its interior  Geologic changes take place very slowly

Structure of the Earth  Three major layers – Core  Inner core - solid  Outer core - liquid Mantle  Solid rock  Very thick Crust  Outermost  Thinnest  Continental crust vs. oceanic crust

Movement Inside the Earth  Occurs in the mantle  Leads to change from internal processes  Two ways it occurs - Convection cells – heated material moves in circles Mantle plumes – heated material moves up and out

Slide 5 Figure 16-3 Page 334 Tectonic plate Collision between two continents Oceanic tectonic plate Spreading center Oceanic tectonic plate Ocean trench Plate movement Continental crust Subduction zone Oceanic crust Oceanic crust Continental crust Mantle Inner core Hot outer core Two plates move towards each other. One is subducted back into the mantle on falling convection current. Mantle convection cell Hot material rising through the mantle Material cools as it reaches the outer mantle Cold dense material falls back through mantle

Plate Tectonics  Crust of the earth is made up of 15 plates that are approx. 60 miles thick  Constantly moving because of the mantle’s movements  Because of their movement, they create: Mountains Trenches in the ocean Volcanoes and earthquakes Evolution of species

Slide 7 Oceanic crust (lithosphere) Abyssal hills Abyssal floor Oceanic ridge Trench Volcanoes Folded mountain belt Craton Mantle (lithosphere) Mantle (asthenosphere) Abyssal plain Continental crust (lithosphere) Mantle (lithosphere) Continental rise Continental slope Continental shelf Abyssal plain Abyssal floor Figure 16-2 Page 333

Slide 8 EURASIAN PLATE CHINA SUBPLATE PHILIPPINE PLATE INDIAN-AUSTRLIAN PLATE PACIFIC PLATE JUAN DE FUCA PLATE COCOS PLATE CARIBBEAN PLATE NORTH AMERICAN PLATE SOUTH AMERICAN PLATE EURASIAN PLATE ANATOLIAN PLATE ARABIAN PLATE AFRICAN PLATE SOMALIAN SUBPLATE Carlsberg Ridge Southwest Indian Ocean Ridge ANTARCTIC PLATE Transform fault East Pacific Rise Transform fault Mid- Indian Ocean Ridge Southeast Indian Ocean Ridge Mid- Atlantic Ocean Ridge Reykjanes Ridge Transform fault Divergent ( ) and transform fault ( ) boundaries Convergent plate boundaries Plate motion at convergent plate boundaries Plate motion at divergent plate boundaries Figure 16-4 Page 335

Slide 9 EURASIA AFRICA SOUTH AMERICA INDIA 135 million years ago Present 65 million years ago 225 million years ago 120°80°0° 120° 80° 40° 120° GONDWANALAND 120° LAURASIA PANGAEA ANTARCTICA AUSTRALIA MADA- GASCAR MADA- GASCAR Figure 5-8 Page 95

Slide 10 Lithosphere Asthenosphere Oceanic ridge at a divergent plate boundary Figure 16-5a Page 336

Slide 11 Lithosphere TrenchVolcanic island arc Asthenosphere Rising magma Subduction zone Trench and volcanic island arc at a convergent plate boundary Figure 16-5b Page 336

Slide 12 Fracture zone Transform fault Lithosphere Asthenosphere Transform fault connecting two divergent plate boundaries Figure 16-5c Page 336

Change via External Processes  Erosion: the process by which material is dissolved, loosened or worn away from one part of the earth’s surface and deposited elsewhere. Contributors – Water, wind, humans  Weathering: the physical, chemical and biological processes that break down rocks and minerals into smaller pieces that can be eroded. Contributors - Freezing of water, oxygen, carbon dioxide, moisture, acids

Natural Geologic Hazards  Earthquakes Plate tectonics rub against each other Releases shock waves Measured by a seismograph Size of the earthquake is represented on the Richter Scale Effects: shaking of the ground, displacement of the ground/buildings, rockslides, fires, flooding, tsunamis

Slide 15 Liquefaction of recent sediments causes buildings to sink Landslides may occur on hilly ground Shock waves Epicenter Focus Two adjoining plates move laterally along the fault line Earth movements cause flooding in low-lying areas Figure 16-6 Page 337

Slide 16 Canada United States No damage expected Minimal damage Moderate damage Severe damage Figure 16-7 Page 337

Natural Geologic Hazards  Volcanoes Magma reaches the Earth’s surface Causes ejecta, lava and gases (carbon dioxide and sulfur dioxide) to be released Sulfur dioxide stays in the atmosphere and is released as acid rain Creates damage to habitats and human development

Slide 18 extinct volcanoes magma reservoir central vent magma conduit Solid lithosphere Upwelling magma Partially molten asthenosphere Figure 16-8 Page 338

The Rock Cycle  The interaction of physical and chemical processes that changes rocks from one type to another  Slowest of the earth’s cyclic processes  3 classes of rocks Igneous rock – formed when magma cools and hardens  Granite and lava rock  Make up most of the Earth’s crust Sedimentary rock – igneous rocks weather and form layers due to pressure  Sandstone and shale Metamorphic rock – sedimentary rock is subjected to heat and pressure  Anthracite, slate, marble

Slide 20 Igneous Rock Granite, pumice, basalt Metamorphic Rock Slate, marble, quartzite Magma (molten rock) Heat, pressure, stress Heat, pressure Melting Sedimentary Rock Shale, sandstone, limestone Deposition Transportation Erosion Weathering Figure 16-9 Page 339

Slide 21 Existence Decreasing certaintyKnown Decreasing cost of extraction Other resources Reserves Undiscovered Identified Not economical Economical Figure Page 340

Lecture 2- Finding, Removing, and Processing Mineral Resources

FACTS:  The United States is the world’s largest energy user  The United States is #1 in using coal to supply energy (26%) with China coming in a close second (24%)

Finding Mineral Deposits  From the air… Aerial photos and satellite images that reveal protruding rock Radiation measuring equipment – detects deposits of radioactive minerals Magnetometers – measure changes in the earth’s magnetic field caused by magnetic minerals Gravimeter – measure differences in gravity caused by differences in density of minerals  Underground… Drilling and extracting core samples Sensors in the ground detect radioactivity Seismic surveys – send shock waves Chemical analysis of water to see if minerals are found in the ground water

Removing Mineral Deposits  Surface mining removes minerals from shallow deposits  Subsurface mining removes minerals from deep deposits

Surface Mining  Mechanized equipment removes the surface of the Earth composed of soil and rock (overburden) to get to the minerals  Waste material that is left is called spoils  There are 5 types of surface mining (all depend on the terrain)

Slide 27 Open Pit Mine Figure 16-11a Page 341 Machines dig holes to remove ore

Slide 28 Dredging Figure 16-11b Page 341 Draglines and buckets scrape up minerals underwater

Slide 29 Area Strip Mining Figure 16-11c Page 341 Earthmovers remove overburden, a machine removes minerals, then overburden is filled back in and the earthmover moves to the next site, parallel to the first

Slide 30 Contour Strip Mining Figure 16-11d Page 341 Power shovel cuts terraces in the side of a hill, earthmover removes the overburden, power shovel removes mineral, overburden is dumped into the terrace below

Mountain Top Removal  Explosives, shovels, and draglines are used to remove the top of a mountain, coal is removed, top is put back  Overburden is released into streams and valleys below

Surface and Mining Control and Reclamation Act of 1977  Requires mining companies to restore most surface-mined land so it can be used for the same purpose as before it was mined

Subsurface Mining  Removes coal and ores that are deep in the ground  Disturbs less land than surface mining  More dangerous and expensive

Slide 34 Underground Coal Mine Figure 16-12a Page 342 Ventilation shaft Shaft Main shaft Lift cage Pumps Coal seams Miners dig a deep vertical shaft, blast tunnels to get to the deposit and use machinery to dig it out and transport it to the surface

Slide 35 Room-and-pillar Figure 16-12b Page 342 Machinery gouges out coal and loads it onto a shuttle car

Slide 36 Longwall Mining of Coal Figure 16-12c Page 342 Moveable support the roof and cutting machines shear off the coal onto a conveyor belt

Slide 37 StepsEnvironmental Effects exploration, extraction Mining Disturbed land; mining accidents; health hazards; mine waste dumping; oil spills and blowouts; noise; ugliness; heat Solid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat Processing transportation, purification, manufacturing Use transportation or transmission to individual user, eventual use, and discarding Noise; ugliness; thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat Figure Page 343 Environmental Impacts of Mining

Slide 38 Percolation to groundwater Leaching of toxic metals and other compounds from mine spoil Acid drainage from reaction of mineral or ore with water Spoil banks Runoff of sediment Surface Mine Subsurface Mine Opening Leaching may carry acids into soil and groundwater supplies Figure Page 344

Slide 39 Surface mining Metal ore Separation of ore from gangue Scattered in environment Recycling Discarding of product Conversion to product Melting metal Smelting Figure Page 345

Slide 40 PresentDepletion time A Depletion time B Depletion time C Time Production C B A Recycle, reuse, reduce consumption; increase reserves by improved mining technology, higher prices, and new discoveries Recycle; increase reserves by improved mining technology, higher prices, and new discoveries Mine, use, throw away; no new discoveries; rising prices Figure Page 345

Slide 41 White clam Magma Black smoker Sulfide deposit White crab Tube worms White smoker Figure Page 348