Energy & Resources Renewable & Nonrenewable

1. Energy & Resources Renewable & Nonrenewable

2. Chapter 15 Geology& Mineral Resources

3. GEOLOGIC PROCESSES • The earth is made up of a core, mantle, and crust and is constantly changing as a result of processes taking place on and below its surface. • The earth’s interior consists of: • Core: innermost zone with solid inner core and molten outer core that is extremely hot. • Mantle: Thickest zone: a rigid outer part, but underneath is asthenospherethat is melted pliable rock that flows in convection currents • Crust: Outermost zone which underlies the continents and oceans • Lithosphere: combination of crust and outer part of mantle

4. Oceanic crust Asthenosphere Lithosphere Continental crust The continental crust is made up of igneous, metamorphic, and sedimentary rocks. It is not recycled within the Earth as often as oceanic crust, so some continental rocks are up to 4 billion years old. More than two thirds of the Earth’s surface is composed of oceanic crust. Oceanic crust is continually formed from mantle material and so is relatively young. Even the oldest parts of the ocean floor are no more than 200 million years old. The Earth’s Crust • The Earth’s crust is relatively thin relative to the rest of the planet. • 25-70 km thick below the continents • around 10 km thick below the oceans. • The crust is rich in oxygen and other lighter minerals such as silicon, calcium and aluminum and is less dense than the mantle. The crust rides over the mantle causing the formation of oceans, mountains and volcanoes.

5. Oceanic Crust Mohorovicic discontinuity Continental Crust Asthenosphere Lithosphere Mantle The Lithosphere • The lithosphere comprises the crust and the upper most region of the mantle. • The lithosphere carries the outer rock layer of the Earth, which is broken up into seven large, continent-sized tectonic plates and about a dozen smaller plates • The lithosphere overlies the hotter, more fluid lower part of the mantle, the asthenosphere. Approx. 70km Approx. 250km

6. GEOLOGIC PROCESSES • Huge volumes of heated and molten rack moving around the earth’s interior form massive solid plates that move extremely slowly across the earth’s surface. • Tectonic plates: huge rigid plates that are moved with convection cells or currents by floating on magma or molten rock.

7. Spreading center Collision between two continents Ocean trench Oceanic tectonic plate Oceanic tectonic plate Plate movement Plate movement Tectonic plate Oceanic crust Oceanic crust Subduction zone Continental crust Continental crust Material cools as it reaches the outer mantle Cold dense material falls back through mantle Hot material rising through the mantle Mantle convection cell Mantle Two plates move towards each other. One is subducted back into the mantle on a falling convection current. Hot outer core Inner core Fig. 15-3, p. 337

8. Plate tectonics is the theory explaining the movement of the plates and the processes that occur at their boundaries.

9. New crust created at spreading ridge Crust cools and sinks into mantle under the influence of gravity Crust melts as it descends into mantle Mantle plume of hotter material rising from near the core Heating and cooling causes convection Plate Movement • Heat from the mantle drives two kinds of asthenospheric movement: • convection • mantle plumes • Plate motion is also partly driven by the weight of cold, dense plates sinking into the mantle at trenches. • This heavier, cooler material sinking under the influence of gravity displaces heated material that rises as mantle plumes. IRON-NICKEL CORE

10. Folded mountain belt Volcanoes Abyssal plain Abyssal floor Oceanic ridge Abyssal floor Abyssal hills Trench Craton Continental slope Abyssal plain Oceanic crust (lithosphere) Continental shelf Continental rise Mantle (lithosphere) Continental crust (lithosphere) Mantle (lithosphere) Mantle (asthenosphere) Fig. 15-2, p. 336

11. Earth’s Major Tectonic Plates EURASIAN PLATE NORTH AMERICAN PLATE ANATOLIAN PLATE CARIBBEAN PLATE JUAN DE FUCA PLATE CHINA SUBPLATE ARABIAN PLATE PHILIPPINE PLATE AFRICAN PLATE PACIFIC PLATE SOUTH AMERICAN PLATE NAZCA PLATE INDIA-AUSTRALIAN PLATE SOMALIAN SUBPLATE ANTARCTIC PLATE Divergent plate boundaries Convergent plate boundaries Transform faults Fig. 15-4a, p. 338

12. Pacific Plate • The Pacific plate is off the coast of California. Lots of volcanoes and earthquakes occur here. • “California will fall into the ocean” idea. • It is the largest plate and the location of the ring of fire.

13. Ring of Fire

14. Plate Boundaries Volcanic island arc Craton Trench Lithosphere Subduction zone Lithosphere Lithosphere Rising magma Asthenosphere Asthenosphere Asthenosphere Divergent plate boundaries Convergent plate boundaries Transform faults The extremely slow movements of these plates cause them to: 1. grind into one another at convergent plate boundaries 2. move apart at divergent plate boundaries 3. slide past at transform plate boundaries. Huge pressures created are released by earthquakes & volcanoes

15. Convergent – the plates push together by internal forces. At most convergent plate boundaries, the oceanic lithosphere is carried downward under the island or continent (subduction zone.) Earthquakes are common here. It also forms an ocean trench or a mountain range.

16. Deep sea trench Active volcano Convergent plate boundary Divergent plate boundary When an oceanic plate collides with a continental plate, it sinks in to the mantle and eventually melts. Subducting plate Convergent Plates: push together • Plate attrition occurs at convergent boundaries marked by deep ocean trenches and subduction zones. The Pacific plate is a convergent plate. Mountain range Oceanic crust Continental crust Mantle

17. Boundaries • Divergent – the plates move apart in opposite directions. Creates oceanic ridges

18. Divergent plate boundary Continental rift zone Magma upwellings through fractures cause plates to diverge. The changing convection currents inside the Earth can cause new boundaries to form and old ones to disappear. Divergent Plates • The size of the plates is constantly changing, with some expanding and some getting smaller. • These changes occur along plate boundaries, which are marked by well-defined zones of seismic and volcanic activity. • Plate growth occurs at divergent boundaries along sea floor spreading ridges such as the Mid-Atlantic Ridge and the Red Sea. Divergent plate boundary

19. New rock on either side of the ridge has the same magnetic information. On average the Earth’s magnetic field reverses once every million years. This leaves magnetic bands in the crust. This shows clear evidence of sea floor spreading and plates tectonics. Sea floor Spreading • Sea floor spreading occurs as magma wells up from the mantle below, forcing the plates apart. • As the new rock cools and solidifies it picks up and preserves the direction of the Earth’s magnetic field.

20. Plate Boundaries • The Earth’s major earthquake and volcanic zones occur along plate boundaries. • The movements of plates puts crustal rocks under strain. • Faults are created where rocks fracture and slip past each other. • Earthquakes are caused by the energy released during rapid slippage along faults. New Zealand’s alpine fault is visible from space, marking a transform boundary between the Indo-Australian plate and the Pacific plate.

21. Continental Boundaries • Where continental plates meet, the land may buckle and fold into mountain ranges. • The highest mountains on Earth, the Himalayas, were formed in this way as the subcontinent of India collided with continental Asia. • Few volcanoes form in these areas because the continental crust is so thick.

22. Boundaries • Transform – plates slide next or past each other in opposite directions along a fracture. • California will not fall into the ocean!

23. Image: NASA Transform Boundaries • Plates may slide past each other at transform boundaries • Plate size is not affected because there is no construction or destruction of material at these boundaries. However, they are responsible for large earthquakes. • Pressure from the plates causes the boundary to lock in position and earthquakes occur when the rock gives way to release the pressure. San Andreas fault Photo: Wiki commons Faultline movement after an earthquake

24. GEOLOGIC PROCESSES • The San Andreas Fault is an example of a transform fault. Figure 15-5

25. Importance • Plate movement adds new land at boundaries, produces mountains, trenches, earthquakes and volcanoes. • Important part of recycling earth’s crust, forming mineral deposits

26. Changing Earth’s surface • Internal processes – rely on heat from earth’s interior – tend to build up earth’s surface • External processes – rely on energy from sun and earth’s gravity – tend to wear down earth’s surface • Erosion: Wind, water, glaciers, human activities especially deforestation (roots hold soil in place) • Weathering: break down rocks, forms soils • Physical – wind, rain, water freezing & expanding • Chemical – reactions with water, acids, gases • Biological – tree roots, lichen

27. The Earth’s Crust Igneous rocks, such as basalt, form a major component of the crust and are essentially unchanged since their formation. Sediments eroded from continents and compressed into sedimentary rock can be later lifted and exposed in mountains The Earth's persistent oceans of liquid water cycle moisture through the atmosphere to the land and back again. Water, as rain, drains to rivers and lakes, which flow back to the ocean eroding the landscape in the process.

28. The Rock Cycle The interaction of physical and chemical processes that turn 1 type of rock into another The slowest of the earth’s cycles; takes millions of years

29. Erosion Transportation Weathering Deposition Igneous rock Granite, pumice, basalt Sedimentary rock Sandstone, limestone Heat, pressure Cooling Heat, pressure, stress Magma (molten rock) Melting Metamorphic rock Slate, marble, gneiss, quartzite Fig. 15-8, p. 343

30. weathering, exposure, and transport, followed by burial deep burial melting cooling and crystallization metamorphic rock deep burial uplift and erosion burial and recrystallization uplift and erosion Extrusive igneous rock metamorphic rock cooling and crystallization Sedimentary rock burial and recrystallization The Rock Cycle The rock cycle constantly redistributes material within and at the Earth's surface over millions of years by melting, erosion, and metamorphism. It is the slowest of the Earth's cycles and is responsible for concentrating the mineral resources on which humans depend. SURFACE LAND SEA ROCKS FORMED AT THE EARTH'S SURFACE CRUST Intrusive igneous rock Metamorphic rock ROCKS FORMED IN THE EARTH'S INTERIOR Magma MANTLE

31. Steps

32. The Rock Cycle • The Earth's rocks are grouped together according to the way they formed as: • igneous • metamorphic • sedimentary rocks • Igneous rocks are created by volcanism and may form above the surface as volcanic rocks or below the surface as plutonic rocks. • Heat and pressure within the Earth can transform pre-existing rocks to form metamorphic rocks. • When rocks are exposed at the surface, they are subjected to weathering and erosion and form sediments.

33. Metamorphic rocks Igneous rocks Sedimentary rocks Types of Rock • The Earth's crust is made up of solid, naturally occurring assemblages of minerals called rocks. • The huge diversity of the Earth's rocks has developed over thousands of millions of years through: • igneous activity (volcanism) main source of mineral resources • metamorphism (changes in form) • sedimentation (formation of sediments and sedimentary rocks)

34. Types of Rock • Igneous rocks solidify from volcanic magma They vary in composition from basalt to granite and in texture from rapidly cooled glasses, such as obsidian, to slowly cooled coarse grains, such as granite. Obsidian Marble Conglomerate • Metamorphic rocks result when pre-existing rock is transformed by heat and pressure. Metamorphic rocks are classified by texture and composition. Examples include gneiss, slate, marble and schist. • Sedimentary rocks form when sediments accumulate in different depositional environments and then become compressed into brittle, layered rocks, e.g. shale, sandstone, limestone, and conglomerate. Granite Schist Sandstone

35. Igneous Rock Classification • Description – forms the bulk of the earth’s crust. It is the main source of many non-fuel mineral resources. • Classification – • Intrusive Igneous Rocks – formed from the solidification of magma below ground • Extrusive Igneous Rocks – formed from the solidification of lava above ground

36. Igneous (Continued) • Examples – Granite, Pumice, Basalt, Diamond, Tourmaline, Garnet, Ruby, Sapphire

37. Sedimentary • Description – rock formed from sediments. Most form when rocks are weathered and eroded into small pieces, transported, and deposited in a body of surface water.

38. Clastic – pieces that are cemented together by quartz and calcium carbonate (Calcite). • Examples: sandstone (sand stuck together), Conglomerate (rounded & concrete-looking) and Breccia (like conglomerate but w/ angular pieces)

39. Sedimentary (Continued) • Nonclastic – • Chemical Precipitates – limestone precipitates out and oozes to the bottom of the ocean (this is why there is a lot of limestone in S.A.) • Biochemical Sediments – like peat & coal • Petrified wood & opalized wood

40. Metamorphic • Description – when preexisting rock is subjected to high temperatures (which may cause it to partially melt), high pressures, chemically active fluids, or a combination of these • Location – deep within the earth

41. Dynamic Metamorphism – earth movement crushes & breaks rocks along a fault. Rocks may be brittle- (rock and mineral grains are broken and crushed) or it may be ductile- (plastic behavior occurs.) • Rocks formed along fault zones are called mylonites.

42. Examples: • Contact Metamorphism- rock that is next to a body of magma • Ex. limestone under heat becomes marble through crystallization • Limestone -> marble sandstone -> quartzite shale -> hornfelds (slate)

43. Metamorphic (Continued) • Regional Metamorphism – during mountain building; great quantities of rock are subject to intense stresses and heat • Ex. cont. shelves ram together

44. Progressive Metamorphism – One form of rock changing into another • shale->slate->schist->gneiss • coal->graphite • granite->gneiss

45. Minerals Mineral: element or compound occurs naturally Mineral resource: concentration that can be extracted Considered Nonrenewable Essential for modern life Metallic: Aluminum, gold, copper Nonmetallic: sand, gravel, limestone Distribution of mineral resources is uneven 4 strategic metal resources: Manganese, Cobalt, Chromium, and platinum are critical and come from unstable countries in Africa – must stockpile Eventually will run out

46. Resources • Many resources are extracted from the different layers of the Earth and some minerals are mined for their uses economically: • Coal, oil, and natural gas are all a mined resource • Uranium is mined for nuclear reactions • Gold, silver, platinum are precious metals and are used commercially • Bauxite is used for aluminum production and are used commercially

47. Oxygen The most abundant element in Earth’s crust Nitrogen: The most abundant element in Earth’s atmosphere Iron: The most abundant element in the Earth’s core. Core also contain nickel.

48. Specific Resources & Their Uses • Limestone – abundant locally, formed from layers of seashells and organisms under pressure as they were covered; used in sidewalks, fertilizers, plastics, carpets, and more • Lead – used in batteries and cars • Clay – used to make books, magazines, bricks, and linoleum • Gold – besides being used as money and for jewelry, gold is used in medicine (lasers, cauterizing agents) and in electronics (circuits in computers, etc.)

49. Texas • Central – limestone, tin, clay, lead, garnets, freshwater pearls, amethysts, calcium carbonate • West – talc, mercury, silver, petroleum, sulfur • East – lignite coal, petroleum • South – lignite coal, petroleum, uranium, limestone • North – helium, uranium, petroleum, bituminous coal

50. United States • Central – diamonds (Arkansas), bituminous coal • West – bituminous and subbituminous coal, gold, silver, copper • East – anthracite coal, bituminous coal • South – some gold (SC), bituminous coal • North – bituminous coal, some gold (SD, WI)