Geosc 10 Final Exam Study Guide PDF

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GEOSC10 Final Exam Study Guide

Chapter 1: Science, Geology, and National Parks   

Science is a successful human activity that allows us to do things we want first by learning how things work. Aristotle thinks if we do A, we expect B to happen, (Newton would expect C to happen) True, Lucky, or Pretty Close

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Scientific Method: o Scientists come up with ideas, and then try hard to prove those ideas wrong. o Get a new idea (hypothesis) and test if the new idea beats the old idea (experiment) o An idea that makes wrong predictions many times is discarded; an idea that makes correct predictions many times is accepted tentatively. o Situations are found in which a new idea makes predictions that differ from those of old ideas

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National Parks: o Problem: parks for “conservation” but “enjoyment” for this generation

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Geology: is the science of the Earth Geologists: o Study the materials that make up the Earth, and the processes that happen to them or have happened to them in the past. o Geologists are helping write the “operator’s manual for the Earth” o Find oil, clean water, metals, and other valuable things in the Earth o Warn people of geological hazards such as landslides, earthquakes, and volcanoes.

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Earth is 4.6 billion years old, pieces of dust and chunks from space fell together under gravity Heating melted Earth and allowed it to separate into layers (denser material sank to the core, lowest-density material rose to the crust o Core: iron-rich o Mantle: iron-silica o Crust: more-silica/less-iron Heating comes from radioactive decay of materials in the Earth

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Rock On #1 1. The US government and most other governments of the world provide support for scientists but not for astrologers, palm readers, or telephone “psychics.” Why do governments support scientists? A: Scientists helps humans do useful things, which makes the humans healthies, wealthier, etc., and governments often like to support health and wealth. 2. What is an accurate description of the job of a scientist? and goes on to show that some of those ideas are false

The scientist invests new ideas,

GEOSC10 Final Exam Study Guide 3. Newton’s ideas on physics “won,” and Aristotle’s ideas were kicked out of science and over into history. Why? A: Newton’s ideas did a better job of predicting how nature would behave 4. When scientists agree that a particular scientific theory is a good one, and the scientists use that theory to help make new things, cure diseases, etc., that “agreement” came about because: A: A number of different experiments by different people all had outcomes that were well-predicted by the theory. 5. Which is more likely to contain reliable information? A: A refereed article in a learned journal 6. The peer review process, in which scientists submit write-ups of their ideas and experiments to a set of colleagues who judge how good the ideas are before the ideas can be published is: A: A useful and important, even if imperfect, mechanism of quality-control for the scientific literature 7. If you could drill a hole straight to the center of the Earth, and keep track of what the hole is going through, you would find: A: You would go through one sort of material, and then a different, denser material, and then a still-different, still-denser material, because the planet is made of concentric layers, sort of like an onion 8. The scientific study of the origin of the planet has taken a lot of effort, and still generates much discord outside the scientific community although almost no discord within the scientific community. The scientifically accepted history is: A: the Earth formed from older materials that fell together under gravity about 4.6 billion years ago 9. National Parks are: Regions containing key biological, geological or cultural resources that have been set aside for the enjoyment of the present generation and future generations 10. In chemistry, the type of an atom (what element it is) is determined by: protons it contains in its nucleus

The number of

11. Chemists recognize many different elements, such as gold, or oxygen, or carbon, or iron. Suppose you got some iron, and started splitting it into smaller pieces. The smallest piece that would still be called “iron” would be: An atom 12. Nuclei of atoms are made up of:

Protons, usually with neutrons added

13. One of the big problems faced by National Parks is that: They must allow people to enjoy things today, and preserve those things for the future, but achieving both of these is not easy 14. Human population continues to grow. Looking at many of the things we use on Earth (farmland and land for wood and other things, fish in the sea, etc.): Our use is large but not everything, we are approaching use of half of all that is available.

GEOSC10 Final Exam Study Guide 15. Which of the following is NOT a job that geology graduates commonly get hired for: Cloning new biological organisms for use in international terrorism

GEOSC10 Final Exam Study Guide

Chapter 2: Making Mountains and Earthquakes 2.1 Plate Tectonics 1: Death Valley  

(Death Valley is growing wider) Devil’s Race Track: The tracks: in the winter, water freezes on top of mud flats and strong winds blow the ice, dragging rocks that are frozen in it Salts left on mud flats by evaporations often contain boron (rare elements leached from volcanic rocks nearby and carried by streams)

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Pull-Apart Faults: o Death Valley is a pull-apart fault o Layers of rock and even recent stream deposits are offset across the faults o The faulting occurs in fits and starts rather than smoothly, producing earthquakes

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The Basin and Range region remain active in producing earthquakes The angled faults require that the region is getting wider o Can measure widening using GPS or very-long-baseline-interferometry techniques o Widening is slow – maybe an inch or two per year across the whole Basin and Range The Gulf of California used to be attached to Mexico, but has been moved out and is still moving out

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Sea-Floor Spreading o Ridge wind through Earth’s oceans like the seam on a baseball o The sea floor is made of young rocks – they hardened as lava cooled recently, with older rocks -they hardened as lava cooled a long time ago o Rocks are progressively older with increasing distance from the ridge o The ridge is shallow and hot o In the ridge, water circulates through cracks in the hot rocks, dissolves many chemicals in the rocks and emerges at black dust

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Heat Inside the Earth: o Heat is just vibration of atoms  Vibrating atoms give off electromagnetic radiation (light)  More heat = more vibration o Temperature is a measure of these vibrations  More vibration = higher temperature o Heat is moved around in 3 main ways:  Radiation, Conduction, and Convection

GEOSC10 Final Exam Study Guide 

Radiation: o Radioactive decay of -uranium, thorium, and radioactive potassium – in rocks, make heat o Most heat comes from this radioactive decay, but some heat is left over from when the Earth was formed, or is being released as the core freezes, or the core, mantle, and crust continue to separate and things sink and give up heart from friction o Electromagnetic radiation is a very effective way to move heat from the sun to the Earth through space and our atmosphere o But radiation is a very inefficient way to move heat through rocks o When an atom gives off electromagnetic radiation, the atom cools and slows unless it receives other energy to speed it up again o

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Conduction: o Moves energy from atom to atom o Very rapid process over short distances (touching a stove) o Very slow process over long distances o If a rapidly vibrating atom (hot) sits next to a slowly vibrating atom(cold), collisions between the two will tend to slow down the fast one and speed up the slow one

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Convection: o As a material heats it rises, and as it cools it sinks “Convection Current” o Heating causes expansion because hotter molecules vibrate more rapidly and tend to bounce farther away from each other  This lowers the density of the material o Low-density materials tend to rise o High-density materials tend to sink o This leads to Convection Currents – a material is heated, rises, cools, and sinks o Rising occurs in one place, the material flows along while it cools, then it sinks and lows back to the rising point o Hotter rocks rise and spread  Rising occurs beneath the ridges in the oceans o Cooling causes contraction and sinking  Together form convection cells o Lithosphere broken into a few big plates that raft around on the convection cells o Where the lithospheric plates are pulled apart, they tend to break o Breaks, in places such as Death Valley, often are angled rather than vertical, and one side slides down along the other, making an earthquake fault

GEOSC10 Final Exam Study Guide

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The Earth: Layered by Composition & Behavior: o Iron core, mantle with silica added to iron, o ocean crust with more silica o continental crust with more silica o Core has solid inner part and liquid outer part o Crust + upper mantle (lithosphere) tend to break, not flow o Deeper in mantle (asthenosphere) tends to flow, not break

2.2 Plate Tectonics 1, Yellowstone:    

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Various lines of evidence indicate that there is a body of melted rock (magma) under the park The water from rain/snow circulate deep through rocks broken by numerous earthquakes and is heated from below The Washburn expedition from Montana visited the region in 1870 and first developed the idea of a national park (park founded in 1872) Geyser Eruption o If cold water on top holds down hot water, the pressure prevents boiling o Eventually, a little boiling manages to expel a little water above, reducing the pressure, allowing more boiling o Geysers require heat Elastic Rebound Theory: o Most earthquakes are produced by elastic rebound o Consider 2 large pieces of rock (southwestern California and the rest of the state): the break separating the different parts is called the San Andreas Fault (both sides are moving westward, but the southwest side has an additional northwesterly movement relative to the northeast side) o The forces that move the rocks are huge and applied over large areas, so that far from the fault the motion is smooth o At the fault, rocks can bend, this bending is elastic and can spring back o Eventually the stress on the rough spots causes the fault to “let go” and the bent rocks “spring back” The break between the two batches of rocks is called a fault, or an earthquake fault

GEOSC10 Final Exam Study Guide 

Seismic Waves o One piece of rock pushed another next to it, which pushes one next to it, etc. o 2 Major Types of Seismic waves:  P – or push  is the ordinary sound wave, represents a push-pull in the direction the wave is moving  Go through solid, liquid, and gas  a P-wave moving to the north will shake a mineral grain north-southnorth-south  can be detected all over Earth  outer core is liquid because it transmits P-waves, not S-waves  S – or shear  Moves slower than the P-wave  An S-wave moving to the north will shake the mineral grains east-westeast-west or up-down-up-down  DO NOT travel through liquids  A P-wave that passes through the outer core loses some energy in making an S-wave when the P-wave hits the inner core  This S-wave passes through the solid inner core, makes a new P-wave when it hits the liquid outer core again, and that P-wave travels on to the surface

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Where Quakes Occur: o Earthquakes occur where rocks are moving past other rocks o Rocks can be pulled apart, because the breaks often are angled rather than vertical, and the upper side slides down over the lower o Rocks can be pushed together, or rocks can slide past each other o Mostly occurs near plate boundaries o Volcanoes can cause small-to medium sized quakes Seismic waves shake buildings

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Size of Earthquakes o Commonest way to measure earthquake size is the Richter scale – a measure of how much the ground shakes during a quake o Richter developed a logarithmic scale:  A magnitude-3 quake moves ground 10 times more than a magnitude-2 quake, which moves ground 10 times more than a magnitude-1 quake  Increase of 1 means increase of 10 in ground motion, and increase of 30 in total energy o The ground motion can be measured with seismographs o Scientists look at P-waves or surface waves to get the size of a quake o Distance can be calculated from  The difference in arrival time between the first P-wave and the first S-wave from the quake to reach the instrument,

GEOSC10 Final Exam Study Guide  

Using the different in speed between P- and S- waves, By timing the arrival of the earthquake at three or more stations and determining where the quake must have been so that the waves arrived earlier at this station than the next o Small quakes are very common and large quakes are rare o Most damage in few, big, rare quakes 

Predicting Earthquakes o The easiest way to predict quakes is to identify those places where quakes are likely to occur o One way is to use patterns of seismicity  If one section of a fault has had a quake every 20 yrs

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Death Valley: Tear-Apart Makes Oceans: o The Gulf of California was formed by spreading, tearing Mexico apart o As the rocks move away from the crack, their weight no longer squeezes the hot mantle beneath the crack o The sea floors of all oceans are made of the frozen crack-filling lava. o Ocean—floor rocks are youngest near the ridges, oldest farther from the ridges o Sediment is thicker away from the ridges because older rocks have had more time for fish to poop on them o Where ridges come up on land, they are ripping continents apart, as at Death Valley and in the East African rifts

GEOSC10 Final Exam Study Guide Chapter 3: Mountain Building and Volcanism 3.1: More Plate Tectonics, Crater Lake  Sea-floor is made of basalt and is made at the spreading ridges o Basalt – melted rock from the mantle that floated to the surface to cool and solidify  When sea floor becomes cold and dense enough, it can sink back into the mantle into the “subduction zone”  As slabs of rock are heated as they go down, a melt if produced and rises to freeze to form andesite.

3.2 Olympic National Park:  Olympic National Park was established for biological and geological reasons o To protect the Roosevelt elk o The rocks are all young – less than 40 million years  The rocks of the Olympic Peninsula are a mix of sea-floor basalts and other sediments  Rivers draining the peninsula carry loads of sediment down to the ocean where is piles on the sea-floor that is slowly moving beneath the continent, a conveyor belt that tries to pull the sediment down to melt and be erupted.  Plate Tectonics Picture: o Earth is heated inside, softening deep rocks of the asthenosphere enough that they can move in slow convection currents that transfer heat from deep to the surface o Heat is conducted through the upper rocks or is erupted, and lost in space o The sea floor rocks in the crust fall between the continents and the mantle in composition o Then, the sea-floor lithosphere consisting of the sea-floor crust plus a little attached mantle will sink into the asthenosphere of the deeper mantle  Plate boundaries include spreading ridges where the plates move apart, and subduction zones where the plates come together and one side sinks under the other  Transform Boundaries (or Transform Faults): slide-past boundaries where plates can slide past each other  Continents grow as the conveyer belt from the mid-ocean ridge to the subduction zone brings in sediments and islands 3.3 Mt. St. Helens:  Mt. St. Helens has been the most active of the Cascades volcanoes over recent centuries  Types of Volcanoes: volcanoes are associated with one of three settings: o Pull-apart margins (spreading ridges) o Push-together subduction zones o Hot spots  Hot spots

GEOSC10 Final Exam Study Guide

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o Deep in the warm, soft, convecting mantle, in some places a rising tower of hot rock forms o As the lithosphere drifts overhead, the hot spot may “punch through” to make a volcano o The lithosphere carries away that volcano and the hot spot punches a new volcano o Hot spots make a string of separate volcanoes, not a continuous line or ridge Type of Volcano depends on temperature, composition, supply of melt, duration of supply, etc. o Composition (how much silica):  Silicon + oxygen = silica  Silica has 4 oxygen atoms which form a tetrahedron  The tetrahedron will stick together into chains and sheets with some oxygens serving in more than one tetrahedron o Volatile content (how much water, and other compounds) o Silica-rich melts form with many volatiles

FINISH 3.3

GEOSC10 Final Exam Study Guide Chapter 4 Mountain Building, Obduction and Tsunamis 4.1 The Great Smoky Mountains: (a thrust fault/push together fault)  Obduction Zones – The Push-Together Boundaries o Older rock sits on top of younger rock o Between the old and young rock is a thrust fault, or push-together fault o Thrust faults show evidence of sliding – scratches and polish indicting motion, breaking of rocks  Thrust faults are of the push-together type. o Squeezing from either side, one set of rocks will be pushed over another set o Each set is right-side up, but where they meet, the older rocks are on top o Can cause folds 

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Push-together forces occur at subduction zones or other collision zones The continents fit together like a jigsaw-puzzle Continents CANNOT sink Continents stand above the oceans because the silica-rich continental crust is lower in density than the silica-poor sea-floor crust The Appalachian Mountains o Older-push-together forces led to closing of a proto-Atlantic ocean that produced the Appalachians o When the proto-Atlantic was closing, subduction-zone volcanoes formed and spread ash layers across the land o When pushing stopping, the Appalachians began to fall apart (like Death Valley) o Older rocks slid over younger ones

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Old, cold sea floor can sink Obduction: layers of rock are bent into folds or broken into thrust faults In subduction, denser side sinks under less-dense side

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The 3 Structural Styles:  Pull-Apart: (Death valley, spreading ridges) o This behavior involves stretching of rocks until they break, forming pull-apart or gravity faults, gravity pulls one block down past the other o Occurs at spreading centers, where the convection cells deeper in the mantle spread apart  Push-together (Crater lake and Mt. St. Helens subduction, State College, and the Great Smokies obduction) o Occurs at subduction and obduction zones o Produces squeeze-together folds and fault (thrust faults)  Slide-Past (San Andreas Fault in California) o Aka “Transform Faults”

GEOSC10 Final Exam Study Guide

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o Occur where 2 large blocks of rack move past each other but not toward or away from each other o Produces earthquakes without mountain ranges Mountain ranges correspond directly to the main boundary types Fault -block mountains form at pull-apart margins o The mountains are high because the rocks beneath them, in the mantle, have expanded because of hot convection cells Volcanic-arc mountain ranges form over subducting slabs, where some of the down going material melts and is erupted to form stratovolcanoes Smaller ranges may form from the sediments scraped off the down going slab Continent-continent or continent/island-arc obduction collisions o occur at convergent or push-together boundaries o produce folded and thrust-faulted moun...