Geology Study Guide Bundle
Geology Study Guide Bundle GEO 101
Popular in Dynamic Earth
Popular in Geology
This 34 page Bundle was uploaded by Carter Cox on Saturday April 30, 2016. The Bundle belongs to GEO 101 at University of Alabama - Tuscaloosa taught by Keene in Spring2015. Since its upload, it has received 28 views. For similar materials see Dynamic Earth in Geology at University of Alabama - Tuscaloosa.
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Geology Study Guide Bundle Exam 2 Where do magma and lava come from? - Magma comes from inside the earth - Lava comes from outside the earth What are the ways magma forms, and how does each work? - Decrease in Pressure o Heat makes rock melt (pressure) o Pressure keeps the rock together o Same heat and less pressure = melt o Pressure happens due to plate tectonics - Adding Volatiles o Evaporate easily o Water is a volatile o Adding volatile makes the evaporation easier o Adding volatile to rock (mostly H2O) makes melt temperature decrease therefore rock melts sooner o Volatile are released from the crust - Heat Transfer o Heat comes up and melts what is above it (Hawaiian Islands Moving) o Decrease in pressure o Adding volatile What are the major types of magma and how/ why are their compositions different? - Felsic o Pink and whit in color, your able to see visible grains o High silica content - Intermediate o “Middle” composition between felsic and mafic o Gray colored - Mafic o High amount of pyroxene, amphibole, and Ca- rich o Dark near black in color - Ultramafic o Very dark commonly green - Why? Their compositions are different because of the silica content and which melts first and last What does the Bowens reaction series tell us about magma formation? - Shows us the order in which minerals form out of melt Why does magma flow and what affects viscosity? - Flow o Because hot things rise o Less dense than solid rock o Squeezed by pressure - What affects viscosity (resistance to flow) o Heat- more heat more flow o Volatile- more volatile more flow o Silica- less silica more flow What are the differences between intrusive and extrusive rocks? - Intrusive rocks o Inside the earth - Extrusive o Outside the earth How do geologists classify igneous rocks? - Composition and texture o Felsic/ intermediate/ mafic/ ultramafic - Texture o Aphanitic Fine grained Cool quickly o Phaneritic Coarse grain Cool slowly o Porphyritic Large crystal with smaller background 2 stages of cooling o Glassy No crystals Very fast cooling Vesicular Cools so fast the gases get trapped o Pyroclastic Volcanic Contains pieces of broken rock In what areas are igneous rocks formed - Subduction zone o Continental arc Felsic o Island arc Mafic - Hotspots - Continental rift zones o Magma- felsic first than mafic - Mid ocean ridge o Mafic - Igneous Provinces o Runny ketchup like magma o Very low viscosity mafic lava Which rock types makes up most continental crust? Most ocean crust? - Granite for continental - Basalt for ocean crust What are the products of volcanic eruptions? What are their characteristics? - Lava - Pyroclastic Material - Gas - Geological Deposits/ rocks What are the main types of lave and why are they different from one another - Basaltic (mafic is runny) o Subtypes Pa hoe hoe Ropey A’a’ Jagged Pillow Lava being squirted in underwater vent - Andesitic o Thick flow (really slow) - Rhyolitic (felsic) (peanut Butter) o Mound up into lava dome because of its thickness What are the differences between the types of eruptions we studied? - Effusive o Low viscosity o Lava is basaltic - Explosive o Lots of pyroclastic debris o Trapped gas explodes What are the main features of a volcano? - Magma chamber o Filled with molten rock - Crater/ fissure o Big hole/ long crack - Vent - Flank Vent o Vent on the side of a volcano - Fumarole o Gas vent - Caldera o Collapsed magma chamber What are the major types of volcanoes? What are their Characteristics? - Sheild Volcano o Low and made of many lateral flows o Mild erruptions o Low viscosity lava o Found on ocean hot spots - Scoria Volcano o Made out of basaltic lapilli pile o Steep sides, deep crater o Symmetrical o Geologically short lived - Strato Volcano o Large steep sides o Alternating layers of lava and pyroclastic material Where do volcanoes occur? - Mid Ocean Ridge o Mafic lava o Sheild volcanoes here - Subduction Zone o Island arc o Strato volcano Gasses from seduction zone o Japan o Continental Arc o Explosive because thicker magma and andesitic lava - Continental Rift Zones o Lots of felsic material o African rift zone - Hot Spot o Area of the globe where heat comes out of the mantle - Oceanic Hot Spot o Ex. Hawaii o Lava is mafic o Eruption type: effusive - Continental Hot Spot o Ex. Yellowstone o Lava is felsic o Eruption is explosive (thick lava) - Flood Basalts o Massive flows from very fluid lava cover vast areas What are the volcanic hazards covered? What are their Characteristics? - Lava o Slowly takes over an area - Pyroclastic Flow o 100- 300 Km/h (flows super fast) o full of poison gas - Ash and Lapilli o Toxic glass shards o Blunt trauma o Aircraft - Blast itself - Landslides o Move up to 250 km/h o Billions of tons of material - Lahar o Water mixed with ash (snow) o Travel over 50 km/h - Earthquakes o Most all major eruption have these - Poison Gas o Can occur with or without eruption o Lake Nyos - Tsunami o Large volume of water caused by blast or collapse can be more damaging than blast What factors help us predict a volcanic eruption? - Earthquake activity o Increases before blast - Heat flow o Increased heat can cause landslides - Volcano shape o Bulges - More gas and steam What are options when it comes to stopping/ protecting ourselves from a volcano? - Determine danger of each volcano - Active o Currently erupting - Dormant o Hasn’t erupted lately, but geologically active - Extinct o Not geologically possible to erupt How to volcanic eruptions affect climate? - High altitude dust may block sunlight o Creates cooler climate - Large eruptions can affect planet - In deep time had profound effect Are there volcanoes elsewhere in the solar system? What are they like? - Extinct o Moon o Mars (Olympus mons) Largest volcano - Active o Io (Jupiter moon) o Saturn Moons What are all the steps in the process of weathering and erosion? - Weathering - Erosion - Transport - Deposition - Lithification What are the principle agents of erosion? - Liquid Water o Most common - Ice o Rare but effective - Wind o Only smaller particles o Cant pick up big things What are the major types of weathering and how are they different from one another? - Physical o Biologically Plant- microbes Animal o Jointing Change in heat and pressure o Frost wedging o Salt wedging Deserts and coasts Abrasion Glaciers, wind, water - Chemical: chemical composition is altered or rock is dissolved o Dissolution Water (and acids within) dissolve mineral All rain is acidic o Hydrolysis Chemical reaction between water and mineral New minerals form o Oxidation Mineral combines with oxygen New mineral forms o Hydration Water absorbs into mineral Expansion breaks up rock o Biological Fungi, lichen, and plants secrete acid What factors affect weathering rates? Why? - Ice - Where its flowing - Chemical processes - Why? Bowens reaction series says mineral weather at different rates How do different size grains act during entrainment, transportation, and deposition? - Entrainment o Act of lifting a particle from a position of rest to be carried in wind or current o Not determined by only size o Has more energy - Transportation o Energy determines the size of the grain because the mineral is being picked up and moved - Deposition o Energy determines size (larger particles/ grains means the less energy) o Deposited somewhere - Why? o Explains why sediments are found in different places o Helps reconstruct past environments o What the earth looked like during a time in history. What are the products of weathering? - Sediments o Loose fragments of rocks or minerals o Includes shells - Soil o Sediment mixed with organic material Why are there different types of soil? - Controlled by: o Parent rocks and minerals o Water content o Climate (heat/ humidity) o Local vegetation o Age How do geologists classify sedimentary rocks? - Detrital - Biochemical - Chemical How are bed, strata, and formation related to one another? - Bed: is a single deposit of sedimentary rock - Strata: layered beds together o Both can be various sizes Know the common stratigraphic structures we covered in class and what they tell us about the rocks in which they are found? 1) Ripple Marks / Dunes a. Indicate moving air or water b. Ripples= small c. Dune= large d. Ripples and dunes can determine flow direction 2) Cross bedding a. Always moving b. Sand piles up then falls to the bottom of the dune c. Layers in different directions 3) Desiccation Cracks a. Which kind of chemical weathering is causing this i. Hydration 4) Graded beds a. Sudden change in water velocity b. Underwater landslides, storms, deltas i. Must be created in a water environment 5) Trace Fossil a. Anything an organism has left behind i. Footprints, burrows worm feet Know the environments of deposition we covered in class. What kinds of rocks would form in each environment? - Environment in which sediment was deposited 1) Glacial a. Glacier = river of ice i. Moves any size grain ii. Glacial till 2) Mountain Stream a. Fast moving water i. Carries small grain away ii. Conglomerates 3) Annual Fan a. Change in velocity i. Arkose (feldspar) – doesn’t last long ii. Conglomerate 4) River a. Heavy grains roll, small grains float b. Flood deposits c. Sandstone, siltstone, mudstone (mudcracks) 5) Lake a. Low energy b. Mudstones c. Varves (fine grained beds) d. Delta at incoming stream 6) Sand Dunes a. Beach and Desert i. Small grains blown away ii. Well sorted limestone iii. Ripple marks and cross bedding What is the significance of a sedimentary basin? - to provide both a source of sediment and a relatively low place for the deposition of that sediment. What do transgressions and regressions tell us? - Transgression o Geologic event during which sea level rises relative to the land and the shoreline moves toward higher ground, resulting in flooding o Can be land sinking or ocean basins filling with water - Regression o Area of submerged seafloor are exposed above sea level Why does sea level change? - tides change this changing the sea level Exam 3 What is the significance of a sedimentary basin? - They are the location of most of the earths hydrocarbon reserve What do transgressions and regressions tell us? Transgressions are when sea level rise – shoreline migrates inland Regression is when sea levels fall- coast migrates seaward Why does sea level change? Ecstatic – global sea level change o Sedimentary- local variation from accumulation and/ or compaction of sediment o Tectonic- continents and/ or sea floor rising and falling How are diagenesis and metamorphism related to each other and what causes each? Digenesis As temperature and pressure increase still in deeper in the subsurface, the changes that take place in the rocks on more profound. At a high temperature and pressure metamorphism begins and make new mineral s The transition between metamorphism and diagenesis occurs between 150 and 300 degrees Celsius What kinds of changes occur during metamorphism? Recrystallization Same mineral, different size and shape of grains Changes the size and shape of grains without changing the identity of the mineral Phase Change Same chemical composition Transforms one mineral into another mineral with the same composition but a different crystal structure Neocrystallization New minerals Growth of new mineral crystals that differ from those of the protolith (Clay and Quartz) turn into (quarts garnet and mica) Pressure solution (Must be in Water) Minerals change shape – elongate Wet rock is squeezed more strongly in one direction than in others. Mineral grains dissolve where their surfaces are pressed against other grains Plastic deformation Happens when a rock is squeezed or sheared at elevated temps and pressures. Under these conditions grains behave like soft plastic and change shape without breaking How do geologists classify metamorphic rocks? Parent Rocks o Component minerals Sandstone- Quartzite Shale – slate Limestone- marble Texture o Foliated- layer or stripes- forms by rotation or recrystallization o Nonfoliated o Shape, size, and arrangement of grains What causes foliation? Foliation- layer or stripes o Forms by rotation and recrystallization What does metamorphic grade tell us? Degree of metamorphic change What do metamorphic facies and index minerals tell us? Metamorphic facies o Group of minerals that are created under specific temperatures and pressures Index Mineral o Tells what forms with specific temperature and pressures Where does metamorphism happen? Contact Metamorphism o Existing rock heated by intruding magma o Low grade metamorphism Regional Metamorphism o Associated with mountain building Burial o Very deeply buried sediment Dynamic o Fault Zones Subduction Zones o High pressure and low temperature Shocks o Meteorite impact What is the rock cycle? Series of processes in which rock forms; Any type of rock can be reformed into any other type of rock What causes earthquakes? Movement of magma Volcanic explosion Giant landslides Water pumping or injection Underground nuclear bomb tests Plate tectonics o New fault or old fault Know the major types of faults, the sub-categories under each, what kind of movement occurs at each fault type, and why that particular type of movement occurs with that fault. Dip slip o Normal – occur where there is tension or stretching of Earths crust o Reverse Thrust- compression (opposite of normal), pops up (mountains), much steeper o Oblique- extension or shorting (moves in two directions at once) Strike Slip o Left Lateral o Right Lateral What is elastic rebound theory and what does it explain? Idea that earth can take a certain amount of pressure o Has a certain breaking point like a twig snapping in half What are the kinds of displacement that occur along faults? how far each side of fault moves away from each other o Fault Creep- moves a little bit everyday o Periodic Energy Release- earth is moving and pressure builds o Store up energy Be able to explain foreshock, aftershock and earthquake triggering. Foreshock- fault is beginning to move Aftershock- fault is adjusting to the new position Earthquake Triggering- more earthquakes outside aftershock area o Hanging wall- rock is above fault o Foot wall- rock is below fault What are the types of seismic waves and their characteristics? Body Wave- travels through the Earth o P- Right to left o S- Up and down o P waves Compressional waves Particle motion is parallel to the wave direction Can go through outer core o S- Waves Shear wave Particle motion is perpendicular to the wave direction Cant move through outer core o Each wave changes velocity depending what they are going through Surface Wave o Love Wave Moves like a snake (side to side particle motion) Deeper you go the less motion o Rayleigh Waves Make a lot of damage, creates most shaking during quake Up, back, around Counter clockwise elliptical particle motion How are earthquakes recorded, measured, and located? Seismograph o Measures intensity, direction and duration of an earthquake Seismograms o Record of ground motion as function of time st Primary wnde- 1 Shear- 2 Locating o P waves are faster than S- waves Determine difference (s-p) Distance 8(s-p) Earthquake size o Magnitude Measure energy release o Intensity Look at damage (centered around humans) o Which earthquake magnitude measurement scale is considered the most accurate? Why? Richter o Uses Maximum amplitude of S- wave S- P time Good for shallow local quakes Mercalli o Based on human experience o Measures damage to humans and their structures Most Accurate o Moment Magnitude Uses Several wave types Rock properties Area of fault Amount of slip Where do earthquakes occur, and where will you find shallow or deep earthquakes? - occur around all of the plate boundaries Deep o Subduction Zones Shallow o Divergent Plate Boundaries Normal fault o Continental Rift Zone Normal fault o Continental collision Zone Reverse and thrust (compression) o Convergent Plate Boundaries Normal and thrust faults o Transform Strike slip fault Center of plate o Rare – 5% o NOT FULLY understood earthquake How and why does each earthquake hazard happen and what are the results? Ground shaking – amount of damage is determined by shaking o Ground Displacement o Land slide- movement of rock and sediment downslope o Liquefaction- mixing of soil and ground water o Fire- stoves, gas, electrical line rupture o Tsunami- wide wave (large volume) 500 MPH can predict only hours o Disease- no clean water, sewage spilling, no transportation Can earthquakes be predicted? What can we do to mitigate the damage? Not really o Can be predicted where but not when To mitigate damages o Monitory USGS Maps o Early Warning Systems o Being Prepared o Construction Techniques What are the factors that determine the kind of deformation that will take place? Type of rock Temperature Pressure Rate of deformation Which geologic features are caused by deformation? What are their characteristics? Faults- brittle Joint- brittle o Natural cracks- no opposing movements o Veins- minerals precipitate in joints Folds- ductile o Compressive strain o Anticline o Syncline o Monocline- stair step o Plunging- asymmetrical o Nonplunging- symmetrical o Basin- bowl- oldest is on the edge o Dome- oldest in the center What information does a geologist get from strike and dip? Strike o Compass direction of outcrop Angle relative to north (measured clockwise) Dip o Perpendicular to strike Measures amount and direction of tilt What happens at each place where orogenies occur? A mountain building event o Subduction Zone Oceanic plate pushes into another creating a mountain o Continental Collision Two plates meet in the middle and crumple up Deforming each other Example: Himalayas o Continental Rifting Stretching, faulting, and volcanoes o What is isostasy? Lithosphere “floats” on asthenosphere o Gravity pulls down lithosphere Idea that earth is always in equilibrium o Squeeze in one place and another place pops out What is a craton? What are the parts of a craton? craton: crust that hasn’t experienced an orogeny for at least 1 billion years, center/ Parts: o Shield- Precambrian Exposed rocks o Platform- Precambrian Rocks covered by sediment Exam 4 Types of Fossilization/ How they work - Frozen or Dried o Fossils of fairly young, measured in thousands of years Ex: permantly frozen in ground - Amber or Tar o Both act as a preservative Amber is like a sticky sap Tar is like sticky oil residue - Permineralized o Minerals precipitate into porous material - Preserved or Replaced o Bones, teeth, shells consist of durable minerals which may survive in rock - Molds and Casts of bodies (Replica or Original) o Conforms to the shape of the shell or body, if body later disappears because of weathering and dissolution, the cavity is called a mold. - Carbonized o Flattened molds created when soft or semisoft organisms are squeezed and pressed between layers of sediment - Trace Fossils o Anything left behind by an organism, including footprints, feeding traces, burrows, and dung - Extraordinary Fossils (DNA) o Chemical Evolution and Natural Selection - Evolution o Both Fact and Theory o Change in population over a succession of generations due to the transfer of inheritable characteristics - Natural Selections o Theory that explains fact o The fitter organisms are going to survive and produce offspring o Same differences are advantages, more advantages = more offspring o Population of organisms are always changing to adapt to their environment Many Different Pieces of Evidence that help us understand how organisms evolve - Anatomy – skeletons, teeth, anything left behind o Fossils o Modern - Vestigial Organ o Organ that no longer functions in the same way that it did - Embryology o Way bone develops - Genetics o PNAS o Phylogenic relationships among their major cetartiodactly subgroups - Biogeography - Homology o Sameness o How anatomy looks the same in different creatures Causes of Extinction - Climate Change - Tectonic Activity o Causes level to rise o Habitat Change - Asteroid or meteor impacts - New predators Techniques or Relative Dating - Original Horizontality o How sediment is deposited Fairly horizontal o Superposition Each layer must be younger than the one below them Oldest is on bottom, and youngest on top o Lateral Continuity Sediments generally accumulate in continuous sheets within a given region Can be distributed later o Cross Cutting Relationships If one geological feature cuts across another, the feature that has been cut is older Baked contact o Igneous rocks “bake” surrounding rocks, so the rock that has been baked must be older Inclusions o Rock containing a fragment of another rock must be younger than the inclusion What do unconformities tell us? - Abrupt transitions in stratigraphic columns o Missing time Non deposition Erosion Fossils for Dating - Principle of Fossil Succession o Fossils found in limited strata o Found in a definable order o Don’t reappear - How we use o Index fossils – Trilobites Well dated Widespread Short lived Geological Column - Represents entire Earths history - Graphic representation of the layers of rock that make up Earths crust - Divided into segments each of represents a specific time interval Radioactive Isotope and Numerical Age - Radioactive Decay o Converts to a different element - Half Life o Time it takes for half of a group of parent isotopes to decay Cannot predict when a single atom will decay - Isotopic Dating o Is like a ticking of a clock, it provides a basis for telling time Characteristics Needed in Order to be dated with Radio Isotopes - Find the right type of elements to work with - Have to have long enough half lives - Steps o Collecting the rocks o Seperating the Minerals o Extracting parent and daughter isotopes o Analyzing parent and daughter ratio From the ration decide age What can be dated with radioactive methods? - Radioactive isotopes only - With useful half lives - Unweather minerals o Volcanic Ash o Carbon o Coral Other Methods Used to Determine Numerical Age - Growth Rings (Dendrochronology) o Rings on a tree o Shells/ coral - Seasonal Layers o Varves o Ice Age of the Earth - 4.55 to 4.6 billion years old What is the extremely general history of human evolution? - Rapidly changing Sources of Energy - Sun (results from nuclear fusion reactions in the Sun) o Solar energy - Gravity o Helps cause tides, flow of water can drive turbines o Falling Water - Chemical Reactions o Inorganic chemicals can burn to produce light and energy - Nuclear Fission o Atoms of radioactive elements can split into smaller pieces - Geothermal o Happens in the center of the Earth - Oil and Natural Gas o Hydrocarbon compounds o Remains of marine algae and plankton How does Fossil Fuels Form? - Remains of organisms o Lived by photosynthesis or by eating algae or plant Where do fossil fuels get trapped? - Anticline - Fault - Salt Domes - Stratigraphic Methods to Extract Fossil Fuels - Tar Sands (Expensive) o Viscous oil in sand o Cannot Pump Mined then heated/ heated then pumped - Oil Shale (Expensive) o Not reached oil window o Mined then heated - Fracking o Hydraulic Fracturing Extracting natural gas o Increases well production o Drawbacks Groundwater contamination Land use issues - Extracting Oil and Natural Gas o Drilling Puncture the seal rock o Pumping Brings oil to surface - Refining Oil o Crude oil is distilled o Process depends on grade Sulfur grade Specific gravity Running Out Oil - Geologists say soon - Economists say we will stop using before Answers - Other sources exists o Liquidfied coal o Oil Shale o Tar Sands o Methane Hydrate Drawbacks of Fossil Fuel use - Air Pollution o Particles and gases/ acid rain - CO2 o Greenhouse gas - Byproducts o Mine runoff - Spills o Groundwater/ ocean - A lot of fatalities Alternative Energy/ Drawbacks Nuclear Power o Energy release when nucleus is split (fission) o Drawback Controlling nuclear reactions Lot of work and planning Potential meltdown o Nuclear waste Damaging to living organisms Long time decay (decades- centuries) Wind o Must have steady breeze o Clean o Drawback Noisy Ugly Hazard to Wildlife Solar o Sunlight converted to electricity o Clean o Drawbacks Not efficient Not cost effective Hydroelectric o Two Kinds River No pollutants Drawbacks o Damns Tidal No pollutants Drawbacks o Construction Geothermal o Use the earths eternal heat where it come near the surface o Used in two ways Water Steam to turn turbines o Drawbacks Conditions limited Final Exam Geology Final Study Guide Scientific Method - Exploration and Discovery - Identifying a Problem - Community Anaslysis and Feedback - Testing Ideas o Interpreting/ gathering data Major Rock Types/ where they’re found - Igneous o Start from hot to cold o “freeze” out of lava/ magma o Found in volcanoes Convergent and Divergent Plate Boundaries - Sedimentary o Detrital- weathering and erosion Clast size, sorting, grain shape, clast composition, cement composition o Chemical o Biochemical o Found near rivers, bottom of mountain, and deep ocean - Metamorphic o Convergent. Middle of mountain o Parent rocks – component mineral s o Texture – foliated/ non foliated What happens at each tectonic boundary? - Convergent o Two plates moving away from each other Subduction zone – reason for earthquakes at plate boundaries Collision - Divergent o Two plates move apart Mid ocean ridge – cooling creates topography, gravity acts on it Continental rift - Transform o Two plates sliding past each other Mostly ocean / ocean o Fracture zone Active is transform Inactive is no longer boundary - Collision o Continent vs continent Cant go down so they go up - Subduction zone o Ocean/ continent o Continental plates never sub duct Dating Rocks - Relative Dating o Original horizontality How is sediment deposited Fairly horizontal o Superposition Apply to Sedimentary only Undeformed Older on bottom Can get tricky o Lateral Continuity Sediments are deposited in continuous layers Can be distributed later o Cross cutting relationships Formations in relation to each other Baked Contact Inclusions - Numerical o Decay and Half Life Unstable atoms eject particles predictably Become more stable atom (14C – 14 N) Parent isotope Daughter Isotope o Half Life Time it takes for half of the population to decay Cannot predict when single atom will decay o Carbon dating o Radioactive decay What do geologists Study - Everything - Every aspect of Earth: land, air, and oceans Why is geology important? - Constantly going on around us - Alabama o Coal, oil, natural gas, iron ore geological resources Basics of Earths history - - How old are the earth and universe o 4.6 and 13.7 - How do we know o By numerical and relative dating - Very general timeline of Earth History o Beginning (no life) o Land then photosynthesis (oxygen/ life) Cambrian explosion Diversified life o Shelled creature then fish, then amphibians, then mammals Major Fossil energy sources/ how to obtain/ how formed - - How do we get them o Mining or fracking/ drilling o Fossil fuel Coal, oil, gas - How are they formed o Over time o Oil is temperature o Coal is carbon and pressure o Aren’t easy to make or preserve Rivers and Streams definitions Hydrologic Circle - Circulation of Earths water supply Tributaries - Side channels that flow into the main channel of a stream Drainage Network - A group of interconnecting stream that form patterns reflecting the underlying geology Dendritic - Drainage network pattern that looks like a branching tree formed due to uniform underlying geology and slope Water Shed - Land area contributing water to a stream Divide - Imaginary line separating one basin from another Continental Divides - Water flowing down either side of this divide will flow to different oceans Permanent Stream - Stream that flows all year long because it is always at or below the water table Ephemeral Stream - Stream that does not flow all year because it is above the water table; dry climate Turbulence - Twisting, swirling motion Discharge - Volume/ time (gallons/ minute) in one section Sediment Load - Total volume of sediment carried Competence - Maximum particle size a stream can carry Capacity - Total quantity of sediment a stream can carry, depends on competence and discharge Deposition - Decrease in velocity that causes sediment to dump out of the water Base Level - Lowest elevation a stream can reach Floodplain - An area next to a stream that regularly gets flooded Recurrence Interval - Average number of year between floods of the same size Annual Probability - The likelihood that a flood of a given size will happen at a specific location during any given time What are ores, formation, and use. - Naturally occurring solid material from which a metal or valuable mineral can be profitably extracted - Economic minerals - Ore deposit – economic significant occurrence of ore How do we extract mineral resources and what are the drawbacks? Hydrologic Cycle - Circulation of earths water supply How do streams erode, transport, and deposit sediment - Down cutting o Relatively clear of sediment Carries sediment that has fallen or slumped into the channel from the stream walls - Undercutting - V- shaped - Stair step canyon - Characteristics landforms of stream systems, how do they form or change - Types of Floods, causes - Seasonal o Wet season- rainfall is heavy o Submerge floodplains- produce floodplain floods Submerge delta plain- delta plain floods - Flashfloods o Floodwaters rise so fast that it may be impossible to escape from the path of the water Effect Humans have on rivers and vice versa - Urbanization o Increased paved areas o Building in floodplains o Pollution - Agriculture o Increase sediment in streams o Change the stream chemistry Fertilizers Animal waste o Ecosystem change - Dam Construction o Changes ecosystem Migrating fish Sediment load Nutrients o Flood control Positive and negative - Overuse- our water o Central Arizona project canal o Los Angeles canal Major features of the ocean floor - Continental Shelf - Continental Slope - Abyssal Plain - Seamounts - Canyons (underwater) o Rivers cut into sediment Types of underlying causes of ocean currents - Currents - Flowing water in defined area o Surface Driven by wind/ affected by Coriolis effect o Deep Down welling Upwelling Caused by Density (thermohaline circulation) Temperature Salinity Causes of Tides - Tides - High and low tides - The larger tidal bulge is on the side closer to the moon - Smaller tide on the other side of earth opposite of the moon - Tidal reach Types of wave and waves action - Waves o Energy moves forward o Water stays put - Open ocean waves o Energy moves forward o Water stay - Breaker o Friction between wave and ocean floor - Wave Refraction - Long shore Current Different Kinds of Coast lines - Tidal Flat - High Tide- covered by water - Low Tide- exposed - Rocky Coast o Embayment o Headland o Always Changing - Fjords o Glacial valley o Flood after glaciers melt - Coastal Wetland o Shallow Water o No Wave Action o Temperate climate Salt marsh o Subtropical climate Mangrove swamp o Coral Reef o Shallow, warm o Grows until conditions change o Erodes into coral sand - Estuaries o Ocean rises into river valley o Mix of fresh and salt water - What determines type of coast? o Tectonic Settling o Sea level o Sediment Supply o Climate Helps stabilize the coastline - Jetty protect harbor entrance - Breakwater- decreases wave energy - Riprap – decrease wave erosion - Beach Nourishment - Bring in new sand - Groin- barrier built to keep sand from eroding Hazards associated with living near the ocean - Growing or eroding away Characteristics of a good Aquifer - Allows water to flow - High porosity and permeability o % Of pore space and ease of flow between pores Size number, shape Groundwater Movement/ how affected by different sediments and rocks - Unsaturated zone, gravity moves groundwater - Saturated zone, pressure moves groundwater - Moves from more pressure to low pressure - All moves slowly o Dacrys Law More permeable = faster Steep slope Easier to move through rocks than sand because rocks have a bigger avenue How do Humans access groundwater? - Wells o Ordinary well o Seasonal Well – only filled with water during some seasons o Artesian well Works like water tower - Spring o Place where groundwater naturally flows to the surface - Hot springs o Hot water comes to surface o Very deep groundwater forced up by pressure or pathway o Geothermal regions Magma near the earths surface Components of a geyser - Water under pressure - Water supply o Recharge - Heat source o Super heated water - Plumbing system o To store water while being heated o Pressure tight Can humans deplete groundwater supplies? - Yes o Lowering the water table o Saline intrusion o Reversing flow o Land subsidence Groundwater Quality - Most is safe to drink - ‘Soft water’ – more salt - ‘Hard water’- lot of calcium, magnesium o erodes pipe - Hydrogen sulfide- rotten egg - Iron- rich Geological Features Created by Groundwater - Caves- form below water table o Limestone in acidic groundwater, water table lowers, cave collapses o Speleothems Calcium filled water Evaporates and deposits calcite o Stalactite Not hollow, water drips off end, grows like icicle o Stalagmite Mound on floor Types of deserts - Subtropical o Global air circulation - Rain Shadow - Coastal - Continent Interior o Far from ocean o Air moisture used over continent - Polar o Global air circulation o Cold air is dry Weathering and Erosion/ Main Causes of Weathering and Erosion Desert Weathering - Physical weathering o Wedging, abrasion, jointing, biological, mass wasting - Chemical o Desert varnish- microbial action on clay Water Erosion - Flash floods - High competency and capacity - High turbulence Wind Erosion - Wind is a fluid- erodes like water o Energy level determines grain size Desert Deposition - Alluvial Fan o Abrupt change in velocity o Stream dumps coarse sediment - Talus Apron o Pile of debris o Gravity - Salt Lake o No outlet o Water collects and evaporates o Salt concentrates - Playa o Dry lake bed - Dunes o Wind moves sand o Wind carries small grains away o Larger grains only move so far Types of Dunes/ Geological Formation - Amount of sand - Wind direction and speed Desertification - Changing non deserts into deserts - Causes o Deforestation o Overgrazing o Agriculture o Water mismanagement o Drought Types of Glaciers - Mountain - Continental - Polar - Temperate Formation - Large amount of snow that doesn’t melt - Gentle slope - Stratified - Compact over time Glacier Movement - Gravity is prime mover - Each glacier is moving at a different rate - Two main types o Basal Sliding Slides on melt o Plastic Deformation Solid changing shape Occurs below about 60 meters Ice cracks above 60 meters - Glacier always move downslope or out from center Glacier Advancing and Retreating - They also advance and retreat o Larger or smaller over time o Advancing- larger o Retreating- smaller o Causes Amount of snow Summer temperatures Glacial Erosion - Incorporation- of rocks - Plucking - Bulldozing - Embedded Rocks o Striations o Polishing o Dust Erosional Landforms - Arête (Knife) o Ridge caused by 2 glaciers - Horn (Matterhorn) o Peak shaped by three glaciers - U- Shaped Valley o Scooped out by glaciers - Hanging valley o Cuts then stops o End abruptly - Fjords o Costal valleys filled with water o Sea level change Global Consequences of Glaciers - Ice loading and glacial rebound o Isostacy - Sea level change History of Glaciation event - Till deposits - Small frequency events - Most resent o Pleistocene Ice age - Ended o 11,000 years ago - How? o Till deposits o Pollen o Fossils Why is New Orleans below sea level/ sinking? - Human activity o Wetland removal No where for water to go o Artificial Levees No new sediment o Extracting Groundwater Comparing sediment - Isostacy o Lithosphere maintaining equilibrium
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