GEOG 104 1st Edition Exam 2 Study Guide Lecture 1 Simple Model of Seismic Refraction Why do seismic waves travel a curving path in the mantle Layered Earth set off by earthquakes and they become more dense Viscous apply pressure to it and it ll move 270 km Upper Mantle Viscous Nickel 410 km 670 km Lower Mantle Solid Fe Iron Mg Magnesium O Oxygen Si Silicon 2230 km 2250 km Liquid Molten These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Iron Nickel Alloy 5150 km Solid Fe 1220 km 1 Temptation decreases from core to crust 2 Pressure increases towards center of Earth 3 Composition Material More pure in the center abundance of minerals increases towards crust Felsic Continental Crust Rich in silica and oxygen Light colored clear white pink Lower density specific gravity 3 0 Viscous Mafic Ocean Crust Rich in iron and magnesium Dark colored dark gray to black Higher density specific gravity 3 0 Less viscous Lecture 2 Theory of Continental Drif Proposed in 1915 by Alfred Wegener Two lines of evidence 1 Shapes of continent fit together like jigsaw puzzle 2 Fossils continents match where continents line up Super Continent called Pangea came together 300 mya fell apart 200 mya Theory was never accepted never knew how it happened and lacked in mechanism for continent movement Convection of the Mantle Magna in mantle rising or sinking due to differences in temperature or composition cool more dense sink warm rises Plate Motion 1 Transform Plates move past each other horizontally 2 Divergent Movement of plates away from each other Rising magma causing plates to spread apart Rifting 3 Oceanic Continental Oceanic plate sub ducts continental plate because it s denser 4 Oceanic Oceanic Denser of 3 plates sub ducts 5 Continental Continental Two continental crusts converging they push together and end up with mountains Crust folds at collision Mountain ranges Lecture 3 Rock Cycle Igneous Felsic intrusive coarse grained fine grained extrusive Igneous Rocks Weathering Transport Cooling Sedimentary Rocks Magma Sedimentary Rocks Clastic clasts or bits of rock or mineral Chemical precipitate chemically Organic forms from carbon based organic matter Clastic 1 2 3 4 5 Sediments erode from continent Transport of sediment by streams Sediments settle on sea floor Burial Lithification Eventual uplift of rock layers Limestone Different types liquidifies Evaporation Halite Gypsum Chemical Organic Precipitated minerals Magma CaCo3 in seashells NaCl in Halite CaSO4 x 2 H2O Igneous 300 million years ago swamp 100 water dirt dead plants Rocks Dirt Coal Sedimentary Metamorphic Batholith Granite gray huge Sill Horizontal plate like Dikes Vertical wall like Exposed Volcanic Neck Ship Rock by erosion Foliated vs Nonfoliated Bands and layers No bands or layers Volcanoes 1 Explosive 2 Fluid Shield 3 Hotspots a Cinder Cone b Composite Pahoehoe Hawaiian term low viscosity lava smooth ropy surface Aa Hawaiian term high viscosity lava jagged Lecture 4 Rock Weathering Physical Weathering Frost wedging freezing causing cracks Salt crystal growth haloclasty series of holes Exfoliation intrusive igneous rocks popping apart due to release of pressure Chemical Weathering Oxidation rust Fe2O3 Hydrolysis rounds rocks off acceptable to erosion strong to weak mineral Dissolution carbonation Biological Weathering Biomechanical tree growing in rock sidewalk with cracks Biochemical breaks down minerals acid causes to grow things on rock Lecture 5 Geomorphology how Earth is changed or formed looking mostly at stuff on surface Process force induces a physical or chemical change in materials or landforms on Earths surface Landforms constantly changing due to interactions of driving resisting forces Driving Forces Resisting Forces Gravity Climate Lithology what rocks is like itself Internal heat radioactive decay friction more resistant rocks Why moving downhill protect less resistant Structure organization of rocks sediment Larger sizes of pebbles have larger angle of repose irregular pebbles bigger than with fine sand smaller Larger particles higher level of repose much steeper than a pile of sand Fine Sand 25 Degrees Coarse Sand 35 Degrees Irregular Pebbles 40 Degrees Mass Wasting Examples Landslides does not behave like a fluid Slumps rotation mass of material moving water to lubricate it Debris Slides material slides downhill gravity little water ex Earthquakes Flows does behave like a fluid Earthflows saturated with water regular soil Mudflows lots of water high rainfall clay holds onto water Debris flows lots of water high angle of repose moves as fluid downhill Other Rock Fall weathering no longer smooth surface vertical falls to ground can be large rocks gravity Soil Creep ex Fence posts leaning downhill happens very slowly by only force of gravity Solifluction areas of permafrost carries soil downhill flows and creeps Lecture 6 Soil Water terms to know Gravitational Water water that moves down through the soil due to gravity Hygroscopic Water water held tightly to clay particles unavailable to plants Capillary Water ability of water to move upwards in the soil through small pore pathways Dry Periods Hygroscopic water no water available to plants Precipitation Water table ground zone capillary water water available Heavy Precipitation Gravitational water Field Capacity maximum amount of water let in the soil after gravitational water has been drained Wilting Point threshold under which soil water is not available to plants minimum Pedogenic Processes 1 2 3 4 Additions Organic matter leaves roots Water infiltration Oxygen Carbon Dioxide Minerals breakdown Sediments Energy from sun Depletions Water Carbon Dioxide Nitrogen Sediments by erosion Energy long wave radiation Water Dissolved Minerals into groundwater Translocations Clay organic matter dissolved minerals carried by water Nutrients circulated by plants Sediments carried by animals ELUVIATION leaching of materials out of upper layers ILLUVIATION movement of materials into lower layers Transformations Organic matter decomposed Weathering particles transformation of minerals Structures formed SOIL FORMING FACTORS CLORPT CLimate Organisms Relief Parent Materials Time Climate humid semi arid arid Organisms bioturbation mixing of soil by plants animals leave behind traces in the soil Relief how it is drained Parent Material Residual soil forms from parent materials in place when
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