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Geog final study guide

by: Cj Sivulka

Geog final study guide Geog 1002

Cj Sivulka

GPA 3.9

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includes notes from class, ppts, and the text book! good luck!
Intro to Physical Geography
Dr Stereletskiy
Study Guide
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This 32 page Study Guide was uploaded by Cj Sivulka on Thursday April 28, 2016. The Study Guide belongs to Geog 1002 at 1 MDSS-SGSLM-Langley AFB Advanced Education in General Dentistry 12 Months taught by Dr Stereletskiy in Spring 2016. Since its upload, it has received 31 views. For similar materials see Intro to Physical Geography in Geography at 1 MDSS-SGSLM-Langley AFB Advanced Education in General Dentistry 12 Months.


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Date Created: 04/28/16
Chapter 12: Soils • Soil  –  relatively  thin  surface  layer  of  mineral  matter  that  normally  contains  a   considerable  amount  of  organic  material  and  is  capable  of  supporting  living  plants;     o About  6  inches  deep   o combination  of  mineral  and  organic  matter,  water  and  air,  living  organisms,   liquid  solutions,  etc   o 25%  air,  25%  water,  5%  organic  matter,  45%  mineral  matter  /  parent  matter   (rock  fragments);  all  of  which  support  plant  growth   • regolith  –  broken  and  partly  decomposed  rock  particles;  covers  bedrock;  kind  of  like  a   blanked  over  the  unfragmented  rock  below  the  soil   • Humus  –  dark  colored  semi  soluble  organic  substance  formed  from  decomposition  of   organic  matter;  “black  gold;”  loosens  the  structure  and  density  of  soil     o Decomposition  is  the  chemical  or  physical  breakdown  of  a  mass  of  matter  into   smaller  parts  or  chemical  elements     • 5  Factors  of  Soil  formation   o Parent  Material  –  the  source  of  rock  fragments  that  make  up  the  soil   § Composition  has  a  direct  impact  on  soil  chemistry  and  fertility   • Ones  rich in nutrients (e.g., limestone and basaltic lava), are easily dissolved in water and made available to plants.   • If low in soluble nutrients (Sandstone), water moving through the soil removes them and substitutes with hydrogen making the soil acidic and unsuitable for agriculture.   o Influence on soil properties tends to decrease with time as it is altered and climate becomes more important   o Climate   § Temperature  and  moisture  are  the  strongest  influencers  to  soil  formation   (they  influence  physical  and  chemical  reactions  on  the  parent  material)   § Climate  also  determines  the  vegetation cover which in turn influences soil development by producing organic matter.   § Precipitation also affects movement of matter through soil.   § As time passes, climate tends to be a prime influence on soil properties while the influence of parent material is less.   § Soils tend to show a strong geographical correlation with climate, especially at the global scale.   o Topography   § Slope  and  drainage  influence  it   § When  soil  develops,  its  vertical  extent  is  continuous  and  slow  changing   § Topography determines runoff of water, and its orientation affects microclimate which in turn affects vegetation.   § For soil to form, the parent material needs to lie relatively undisturbed so soil horizon processes can proceed.   § Water moving across the surface strips parent material away impeding soil development.   § Steep slopes have poorly developed soils •Flatter terrain accumulates soil faster   § Soil is thinner on slopes because of erosion   § Steep slopes don’t have any soil development   § Residual soil is developed on bedrock   o Vegetation  /  Biological  factor   § Influences  it  through  litterfall  and  process  of  decomposition  because   organisms  add  organic  matter  and  nutrients  to  the  soil  which  influences   soil  structure  and  fertility     § Surface  vegetation  also  protects  the  upper  layers  of  soil  from  erosion   § Animals  live  in  the  soil  and  can  tunnel  through  it  Vegetation  roots  provide   aeration  and  drainage  roots     § Nutrient  Cycling   • Biotic elements of the environment need life-sustaining nutrients that find their origin in the soil.   • Upon their death, organisms return these nutrients to the soil to be taken up again by other plants and animals.   • Hence there is a constant cycling of nutrients between organisms and soils.   • Without it, soluble nutrients would be removed from the soil by percolated water, decreasing the soil's ability to support life.   o Time  –  slow  process   § Influences the temporal consequences of all of the factors described previously § Soils get better developed (Thicker, with greater differences between layers) with more time § Climate interacts with time during the soil development process. § Soil development proceeds much more rapidly in warm and wet climates thus reaching a mature status sooner. § In cold climates, weathering is impeded and soil development takes much longer. • Horizons  –  soil  layers   • Soil  profile  –  all  the  soil  horizons  taken  together;  from  surface  to  bed  rock   • Horizon  development  process;  basically  what  goes  in  and  out  of  the  soil  and  how  stuff   moves  around  in  the  soil     o Additions  (for  soil  enrichment):  water,  oxygen,  carbon,  nitrogen,  chlorine,  sulfur,   organic  matter,  sediments,  energy  from  the  sun     o Translocation:  clay  and  organic  matter  carried  by  water,  nutrients  circulated  by   plants,  soluble  salts  carried  in  water,  soil  carried  by  animals,  chemicals,     o Transformation:  organic  matter  converted  to  humus,  particles  made  smaller  by   weathering,  structure  and  concentration  formation,  minerals  transformed  by   weathering,  clay  and  organic  matter  reactions     o Loss  /  Removal:  water  and  minerals  in  solution  or  suspension;  chemicals,   particulates,  organic  matter   • Soil  movements     o Eluviation  –  downward  transport  of  fine  soil  particles,  removing  them  from  the   upper  soil  horizon   o Illuviation  –  accumulation  in  a  lower  soil  horizon  of  materials  eluviated  from   higher  horizons     • Soil  Horizons       o O  horizon  –  loose  and  partly  decayed  organic  matter   o A  –  mineral  matter  mixed  with  some  humus;  dark  colored  horizon  of  mixed   mineral  and  organic  matter  and  with  much  biological  activity     o E  –  zone  of  eluvation  and  leeching;  a  alight  colored  horizon  marked  by  removal   of  clay  particles,  organic  matter,  and/or  oxides  of  iron  and  aluminum   o B  –  accumulation  of  clay,  iron  and  aluminum,  from  above;  zone  of  illuviation   o C  –  partially  weathered  parent  material     o R  –  unweathered  parent  material;  consolidated  bedrock     • Soil  in  Boreal  forests  –  (spodosols);  pine  trees  have  low  nutrient  demands  so  the  litter  is   poor;  little  cycling  of  the  nutrients  occurs;  precipitation  also  flushes  some  organic   material  from  the  soil     • Soil  in  the  warm  and  wet  tropics  –  (oxisols);  Bacterial activity proceeds at a rapid rate, thoroughly decomposing leaf litter; Available nutrients are rapidly taken back up by the trees; High annual precipitation flushes some organic material from the soil; Create soils lacking much organic matter in their upper horizons.   • Soils  in  grasslands  –  (mollisols);  some  of  the  richest  in  the  world;  lots  of  rich  humus;  fast   accumulation  of  nutrients;  low  leaching     • Soil  Properties   o Color  -­‐  A  product  of  soil  forming  processes;  usually  red,  gray  or  white,  or  black  or   brown;  colors  give  strong  hints  about  soil  fertility     o Texture  –  refers  to  the  relative  proportion  of  sand,  silt,  and  clay  size  particles  in  a   sample  of  soil;  sand,  slit,  clay  refer  to  particle  size;  you  use  a  soil  texture  triangle   to  classify  the  texture  class   o Structure  –  refers  to  the  way  in  which  soil  grains  are  grouped  together  into  larger   masses  (peds  –  an  individual  natural  soil  aggregate);  soil  structure  has  a  major   influence  on  water  and  air  movement     § Granular  structure  –  where  the  structural  units  are  approximately   spherical  and  are  bounded  by  curved  or  irregular  faces  (look  like  cookie   crumbs!);  allows  water  and  air  to  penetrate  the  soil   § Blocky  structure  -­‐  the  structural  units  are  blocklike;  the  strongest  blocky   structure  is  formed  as  a  result  of  swelling  and  shrinking  of  the  clay   materials  which  produce  cracks     § Platy  structure  –  looks  like  stacks  of  dinner  plates  overlaying  one  another;   platy  structure  tends  to  impede  the  downward  movement  of  water  and   plant  roots  through  soil   o Soil  water   § Infiltration  capacity  is  the  maximum  rate  at  which  water  (falling  rain  or   melting  snow  can  be  taken  in  (absorbed)  by  soil  through  the  surface)   • Infiltration  capacity  –  amount  (depth)  /  time   o F  =  d/t   • Different  values  of  F  for  different  soil  textures     o EG:  coarser  soils  have  higher  infiltration  capacity     § Field  /  storage  capacity  –  maximum  capacity  of  soil  to  hold  water  against   the  pull  of  gravity     • Sand  is  7%;  peat  is  greater  than  170%     § Types  of  soil  water   • Hydroscopic  water  –  water  that  is  bound  to  soil  particles  due  to   molecular  forces;  can’t  be  evaporated,  used  by  plants,  or  removed   by  any  other  natural  process   • Capillary  water  –  the  part  of   soil  water  which  is  held  as  a   continuous  layer  around   particles;  most  of  it  is  available   to  plant  roots     • Gravity  water  –  subsurface   water  that  responds  to   gravitational  force,  percolating   it  through  the  soil     o Chemistry  –     § some  elements  are  required  for  plant   growth   • Calcium  (Ca++)   • Magnesium  (Mg++)   • Potassium  (K+)   • Sodium  (Na+)   § Colloids   • Plant nutrients (bases) are attracted and held by very small organic and mineral particles (colloids).   • Colloids generally have a net negative charge as a result of their physical and chemical composition.   • One of the most important properties of colloids is their ability to attract, hold, and release ions.   § Ion Exchange- the exchange of an ion in the soil for another on the surface of a colloid.   • The capacity of a soil to retain and exchange ions, is called its exchange capacity.   o Exchange capacity - measure of the chemical reactivity of the soil, varies inversely with particle size. Fine soils accumulate and retain many times more ions than do coarse soils.  The exchange capacity of the soil's colloidal particles is of tremendous importance. Nutrients that would otherwise be washed away are held in reserve and become available to the plant.   § Cations differ in their ability to replace one another; if present in equal amounts, H+ replaces Ca++ replaces Mg++ replaces K+ replaces Na++. If one ion is added in large amounts it may replace another by sheer force of number. This is largely what occurs with the addition of fertilizer. The release of hydrogen ions in soils tends to promote the exchange of ions, making them available to plants.   § Ph  -­‐  H+ concentration in the soil is measured in terms of the pH scale. Soil pH ranges from 3 to 10. Pure water has a pH of 7 which is considered neutral, pH values greater than seven are considered basic or alkaline, below seven acidic. Most good agricultural soils have a pH between 5 and 7.   § Pdeogenic  regimes  –     • Laterization Eluviation and leaching of A horizon in wet warm climates (red soils, Fe, Al) • Podzolization Eluviation and leaching of A horizon in cold temperate climates (ash like A, yellow B) • Gleization Reduction of Fe+++ to Fe++ in anaerobic environment • Calcification Calcic hardpans (prairies/steeps) in dry conditions • Salinization Accumulation of chlorides, sulfates in desert climates • Naming and Labeling of Soils o Soil taxonomy – generic; soil is organized based on observable soil characteristics; focus on the existing properties of the soil rather than on the environment, process of development, or other properties • Classifications o Alfisols § Al stands for aluminum and F stands for iron; lots of these 2 elements in the soils; clay accumulation with high bases; most wide ranging of mature soils o Andisols § Andesite, rock formed from a type of Magmum in the Andes Mountans volcanoes; lots of ash o Aridisols § Dry soils; 1/8 of the earth’s surface; requires irrigatoin o Entisols § Very little profile development; sandy / droughty conditions; 12% in Us mostly in west; were recently formed (recENT) o Gelisols § Permafrost layers; in the polar and alpine regions; freezing § Soils of very cold climates that contain 2 meters of the surface § These soils are limited geographically to the high latitude polar regions and localized areas at high mountain elevations § Has a high percentage of organic matter because of the slow rate of microbial decomposition in cold climates o Histosols § Organic soils; cover a small area (2% of US); essentially peatlands, large carbon; living tissue; mostly organic matter o Inceptisols § Few diagnostic features; adolescent in various environments, young soils; beginning of soils in their life o Mollisols § Soft, dark, 22% of the US; excellent for agriculture o Oxisols § highly weather and leached; warm, rainy areas; soils with large amounts of oxygen containing compounds o Spodosols § Acid, sandy forest soils; coniferous forests; wood ash; ashy soils o Ultisols § Soils that have had the last of their nutrient bases leached out; clay accumulation with low bases o Vertisols Chapter 13: Introduction to Landform Study • The Earth interior o Crust – outermost solid layer § 1% of the earth’s volume § 7-70km o mantle – beneath the crust and surrounding the outer core; 2900km, 84% volume § Lithosphere – crust and uppermost zone of mantle § Asthenosphere – layer of the upper mantle and underlying lithosphere; very hot, weak, and easily deformed § Mesosphere – rigid part of the deep matle o Outer core – molten shell beneath the mantle that encloses Earth’s innter core o Inner core – primarily solid: iron nickel alloy • The Composition of the Earth – 100 natural chemicals in the Earth’s crust, mantle, and core o Minerals are the building blocks of the rocks o Solid when – atoms are arranged in a regular pattern to form solid crystals o Naturally found in nature and are organic o Have a specific chemical composition § Silicates, oxides, sulfides, carbonates, halides, native elements o Rocks are consolidated combinations of minerals • Bedrock – buried layer of the residual rock that has not experienced erosion (underneath regolith and soil) • Igneous rocks are formed by solidification of molten magma o Extrusive – volcanic rock; molten rock aka magma is ejected onto the earth’s surface and solidifies in the open air; (lava is when it is out of the earth); pyroclastic § Can see the horizontal layers like on river beds o Intrusive – plutonic; rocks that cool down and solidify beneath the earth’s surface; granite is intrusive • Sedimentary Rocks – formed by sediment consolidation; pressure and cementation o Sediment is material that is broken down by natural processes and is subsequently transported by the action such as wind, water, and ice o Sediment is formed by particles deposited by wind or water and it builds up layers and compacts; cementation happens when pores between the dirt are filled by cementing agents like silica, calcium carbonate, iron oxide o Sedimentary rocks form: § In terrestrial environments – rovers and flood plains (fluvial and alluvial); lakes (lacustrine); deserts (Aeolian environment) § Marine environments – continental shelf; continental slope; abyssal plain; beach and barrier islands o Abundant types of sedimentary rocks • Sandstone – compacted sand grains o Shale – compacted silt and clay particles; most abundant o Limestone – chemically or organically produced (calcium carbonate; skeletal remains lime secreting creatures) • Metamorphic rocks – originally was a different type of rock (like sedimentary or igneous) but was changed by heat and / or pressure within the earth • Ocean floor rocks o Basalt (dense rock) covered with thin layer of sediments o Ocean crust sima rock • Isostasy – isostatic equilibrium o Huge plates of crustal and upper mantle material (lithosphere) “float” on more dense, plastically flowing rocks of the asthenosphere. The “depth” to which a plate, or block of crust, sinks is a function of its weight and varies as the weight changes. This equilibrium, or balance, between blocks of crust and the underlying mantle is called isostasy. The taller a block of crust is (such as a mountainous region), the deeper it penetrates into the mantle because of its greater mass and weight. Isostasy occurs when each block settles into an equilibrium with the underlying mantle. Blocks of crust that are separated by faults will “settle” at different elevations according to their relative mass (Figure ) o Crust floats on the denser, deformable mantle below o There is a gravitational equilibrium at Earth’s crust; where material is added, crust will sink, remove and the crust will rise Geomorphological Processes • Geomorphological processes – what changes the earth o Endogenic – energy from within the earth that changes it § Internal § Geothermal energy § Tectonics, igneous activity, metamorphism § Orogeny / orogenesis (vertical displacement; mountain ranges) § Epeirogeny / Epierogenesis (vertical displacement; entire continents) § Mainly relief construction o Exogenic – energy outside the earth (like atmosphere) that changes it § External § Solar radiation § Denudation: weathering, erosion, transport, deposition § Mainly relief reduction • Erosion wears down a landmass through a predictable series of stages, to a surface of low relief; landscapes can be young and old (relative) • Internal Processes – originate from within the earth; initiated by the internal energy that generates forces that apparently operate outside of any surface or atmospheric influences o Plate tectonics o Volcanism and plutonism o Folding o Faulting o Earthquakes • External processes – operate at the base of the atmosphere; draw their energy mostly from source above the lithosphere, either in the atmosphere or in the oceans o Weathering o Mass wasting o Erosion / deposition • Continental drift – theory to explain Pangea o Originally proposed by Alfred Wegner in 1912; his theory was rejected b/c the ocean floor was too strong to be plowed aside; and because wegner had not proposed a plausible force that could induce the continents to drift o Evidence for continental drift § 1. Fit of coastlines – coastlines of the continents fit together like puzzle pieces § 2. Godwana ice age – finding of tilltes (glacial sediments) in similar places where Pangea was near the south pole § 3, mesosauurus – same animals found on coasts of continents – would’ve been impossible if these continents had not once been touching § 4. Matching mountain ranges § 5. Pole wandering § 6. Sea floor spreading – cracks in the seafloor where they split; midocean ridges are formed by currents of magma rising up from the mantle; volcanic eruptions create new basaltic ocean floor that spreads away from the ridge § 7. Global seismicity – earthquake cracks • Plate tectonics – the combination of the concept of transform faults with the hypothesis of sea floor spreading led to the construction of the theory of plate tectonics; the theory states that the lithosphere is divided into an interlocking network of blocks named plates • Plate boundary movements o Divergence – seafloor spreading o Convergence – collision o Lateral – transform (one goes up one goes down) • Divergent plate boundaries (where they split apart) – are the origin of ocean basins • Rift valley formation - near-shaped lowland between several highlands or mountain ranges created by the action of a geologic rift or fault; formed on a divergent plate boundary, a crustal extension, a spreading apart of the surface, which is subsequently further deepened by the forces of erosion o Begins on a continent o Grows to be come linear sea o A constructive boundary out of rock is created • Convergent plate boundary: ocean to continent – subduction trenches (the slab is pulled next to continents) o The rock is destroyed by subduction; one plate going over the other o Continent plate goes over sea plate o Andes mountain • Convergent plate boundary: ocean to ocean o Subduction trenches deep in the ocean o Rock is destroyed via subduction o Aleutian islands, marina islands • Convergent plate boundary: continent to continent o No subduction o Conservative boundary- rock is neither created or destroyed but pushed up o Makes mountains like the humalayas • Volcanism o Lava – exposed magma o Magma – molten mineral material below the surface that is extruded onto the surface of the earth o Pyroclastic material – solidified materials such as solidified lava blobs, rock fragments, ash, and dust thrown into the air by explosive volcanoes • Types of landforms associated with volcanic activity o Shield volcano – never steep sided; wide; big, largest; high layer upon layer of solidified lava flows; gentle angles; large base; created from basalt; characteristic of the midocean region; basalt has a lot of sand so the lava flow is slow o Composite volcano – steep sided, large, symmetrical cone, layers of pyroclastic material; erupt explosively; can grow tall but not as tall as shield volvanoes o Cinder cone – smallest; steep sided; loose pyroclastic material; 500 meters tall; result of a single eruption • Plate tectonics and hot spots o Hawaii, along the coast of cali, along plate tectonics o Volcanoes are distributed based on the locations of plate tectonics o Volcanoes that aren’t along the edges of the plates are called hotspots – spots that have mantal flumes (much higher temperature of magma); these are the special areas because they sit in the same location regardless of where the plates are moving • Plutonism: ingenous intrusions o Vertical ones are called dikes o Horizontal intrusions are called sills o Baleolith – a very large igneous intrusion extending deep in the earth’s curst • Tectonism or Diastrophism o General term referring to the deformation of the earth’s crust; implies the material is solid and that there’s plate boundary movement § Implies the material is sold § Plate boundary movement – variety to unknown causes § 2 types: folding and faulting • Folding – lateral pressure causes bending in the sedimentary rocks; happens when the rock bends and not breaks o Syncline – a sequence of folded rocks with the youngest rocks on the inside of the fold (at the surface) o Anticline – a sequence of folded rocks with the oldest rocks on the inside of the fold (below the surface) o In the Appalachian mountains in the eastern US, most anticlines and synclines are plunging folds ( V fold goes into the ground) rather than horizontal folds (remains parallel with the ground) o Ridges – when the folded rock turns sharp and stiff o Valleys – when the folded rock turns out smooth and wavy • Faulting – breaking apart of crustal material o Displacement o Occurs in zones of weakness in the crust at the fault line or zone o Types of faults – regardless of size, all faults are classified by the direction of the relative movement which is called the slip § Dip slip faults (normal and reverse) – pulling away at the faults or pushing together at the faults • Motion of the blocks is parallel to the direction o Normal movement is down dip o Reverse movement is up dip § Strike slip faults (left and right lateral) • Horizontal side to side grinding at the fault • Right lateral and left lateral § Oblique slip faults • Displacement both vertically and horizontally § Reverse fault – when 2 blocks collide together and one is pushed on top of the other • Earthquakes – vibration of the earth produced by shock waves resulting from the sudden displacement usually along a fault; release tension accumulating across the plate tectonics o Earthquake waves § P waves – fastest moving, alternately compressing § S waves – slower moving, producing both side to side and up and down motion o Seismic waves – energy waves in an earthquake that originate at the center of the fault motion o Magnitude – calculated on a logamartihic scale § Least understood § Difference between a 3 and a 7 is 1,000,000 times energy § Common scale is richter scale CH15: Preliminaries to Erosion: Weathering and Mass Wasting • Denudation o Overall  effect  of  the  disintegration,  wearing  away,  and  removal  or  rock  material  (i.e.   lowering  of  the  surface  of  continents) o Three  processes § Weathering  –  breaking  down  rock  into  smaller  components  by  atmospheric  and   biotic  agencies § Mass  wasting  –  short  distance,  downslope  movement  of  broken  rock  material   due  to  gravity § Erosion  –  more  extensive  and  distant  removal,  transportation  of  fragmented   rock  material • Weathering  (rocks  are  broken  down)   -­‐-­‐>  Mass  Wasting  (gravity  moves  deb ris)-­‐-­‐>  Erosion   (weathered  debris  is  removed)  -­‐-­‐>  Deposition  (debris  is  deposited) • Weathering  is  the  initial  stage o It’s  the  disintegration  and  decomposition  that  destroys  rock ;  rock  is  fragmented  into   small  pieces,  the  atmosphere  is  a  key  agent  in  weatheri ng   o 3  main  types  (mechanical  chemical  and  biological) § Mechanical  /  physical  weathering   -­‐  the  mechanical  disintegration  of  rock   without  a  change  in  its  chemical  decomposition • Thermal  expansion  and  contraction   -­‐  enlargement  and  reduction  in   volume  in  response  to  heating  and  cooling;  when  a  rock  is  heated  it   expands,  when  it  is  cooled  it  contracts;  different  minerals  expand  and   contract  at  different  rates • Exfoliation  – o Mechanical  exfoliation   -­‐  rock  expands  and  cracks  as  pressure  is   reduced  due  to  removal  of  overlaying  material;  rocks  below  the   earths  surface  support  the  weight  of  the  overlying  column  of   rock;  buried  rocks  are  slightly  contracted  under  pressure;   erosion  or  tectonics  strops  away  overlying  rock  and  decreases   pressure  on  buried  rocks;  this  results   in  release  of  the  pressure   that  forms  parallel  to  the  surface;  with  continued  exposure  of   buried  rock  slabs  of  rock  break  long  the  pressure  release   fractures;  this  is  called  unloading o Unloading  exfoliation   -­‐  Stripping  away  of  roughly  parallel,   cocentric  rock  slaps;  curved  layers  peel  off  bed  rock ;   deformation  of  rock  due  to  the  relief  of  confining  pressure  of   overlying  rock • Frost  wedging  -­‐  expansion  of  water  in  the  rock  and  cracks  the  rock • Crystal  growth  –  salt  crystals  grow  from  evaporated  salty  water;   in   desert  an  semi  desert  environments,  water  on  the  surface  or  in  th e  soil   is  often  evaporated;  as  water  evaporates,  salts  that  were  dissolved  in   the  water  are  forced  to  crystalized § Chemical  weathering  -­‐  reactions  involve  exchanges  of  materials  between   reactant  and  the  rock;  principal  agents  of  chemical  weathering:  oxygen,  water,   carbon  dioxide • Agents  in  chemical  weathering:  oxidation,  hydrolysis,  carbonation o Oxidation  -­‐  Oxygen  attacks  the  minerals  containing  iron,   forming  red  oxides  =  reddish  rock o Hydrolysis  -­‐  Water  attacks  hydrogen  and  hydroxide  in  rock,   displacing  potassium,  sod ium,  calcium  and  magnesium  ions;   hydrolysis  is  the  most  common  weathering  reaction  on  earth o Carbonation  -­‐  A  weak  carbonic  acid  converts  limestone  to   dissolved  calcium  and  biocarbonate s;  deeply  pitted  surface  of   the  limestone;  rainfall  erodes    the  limestone  into  pits  and   channels  by  dissolving  it   • Spherodial  weathering  –  when  the  chemical  weathering  makes  rocks   spherical   • Rates  of  chemical  weathering    -­‐  Australians  do  this  with  rocks  in   graveyards  and  dates   § Biological  weathering • Direct • Biophysical   Biochemical   Root  pressures,  growth  stresses,   Bacterial  redox,  chelation,   wetting  and  drying,  mechancial   cation  exchange,  solution   boring   • Indirect  -­‐  soil  mixing;  production  of  organic  acids   and  CO2;  organic   layers  protecting  a  surface • Biological  agents  in  weathering • Root  weathering  -­‐  where  tree  roots  influence  pavement • Lichens  and  mosses  open  fissures  and  rocks  and  scrounge   nutrients   • Rates  of  weathering • Relative  resistant • Permeability  /  porosity • Quartz  content • Jointing • Relative  exposure • Increasing  surface  exposure  of  rock  accelerates   weathering • Vegetation • Interception  rate;  infiltration  rates;  organic  matter  production • Altitude • Mechanical  (freezing  /  thawing)  increases  in  importance  with   higher  altitude  /  elevation • Chemical  increases  in  importance  at  lower  altitudes  especially   with  increase  in  vegetative  cover • Slope • Inverse  relationship  between  slope  and  interception,  infiltration,   vegetative  cover • Direct  relationship  between  slope  and  materia l  transport o Regolith – a product of rock weathering – the amount of weathering increases towards the surface • Mass wasting is step 2 of denudation (after weathering = 1 stage) st o Intermediate  stage  is  the  mass  wasting;  gravity  is  the  energizing  force  behin d  mass   wasting o Mass  movements   -­‐  any  unit  of  movement  of  a  body  of  material,  propelled,  and   controlled  by  gravity  (2  major  categories:  landslides  (rock  and  soil);  avalanches  (snow   and  ice) o Major  mass  movements   -­‐  seismic  activity,  atmospheric  elements o Increasing  risk  of  this  worldwide  -­‐  land  hunger  (Barrio  settlements) § Up  to  90%  of  landslide  deaths  occur  on  the  pacific  rim § US  economic  loss  well  over  $1  billion  a  year § Death  total  is  usually  low,  speed  off  the  slide o Landslides  –  downslope  movement  of  rock  and  s oil  debris  that  have  been  separated   from  the  underlying  slope;  occur  when  the  strength  of  the  material  comprising  the  slope   is  exceeded  by  a  downslope  stress   § Mechanics  of  landslides • D=driving  force  or  shear  stress • S  =  resisting  force  or  shear  strength • Landslides  occur  when  D>S • N  =  normal  force;  force  perpendicular  to  the  slope • W  =  weight  of  the  material,  vertical  pull  of  the  vravity • A  =  angle  of  the  slope • Angle  of  repose  -­‐  the  maximum  angle  at  which  a  material  can  remain  at   rest  on  the  slope § Landslides  occur  in  areas  where  there  is:  seismic  shaking;  high  relief,   mountainous  environments;  moderate  relief,  severe  land  degradation;  areas   with  loose  deposits;  areas  with  high  rainfall o Types  of  mass  wasting    -­‐  movement  of  debris  (mainly  rock)  transported  through   the  air § Fall  –  movement  of  debris  (mainly  rock)  transported  through  the  air;  presence   of  water  freeze-­‐thaw  cycle;  earthquakes;  slopes  steeper  than  40  degrees;  on   some  roadways,  there  is  mesh  that  prevents  rock  from  covering  roadway § Slide  –  can  be  rock  or  land;   • Rockslides  can  happen  suddenly  with  rapid  downslope  movement  of   talus • Landslides  –  happen  when  the  movement  of  rock  and  soil  slip  along   surfaces  due  to  gravity o Two  main  types § Rotational  slides  (slumps);  curved  slip  surface § Translational  slides  –  relatively  uniform,  planar  surfaces;   block  glides  and  debris  slides o Landslide  warning  signs:  doors  or  windows  jam  for  the  first   time;  new  cracks  appear  in  plaster,  tile,  brick,  or  foundations;   outside  walls  or  stairs  begin  pulling  away  from  building;  slowly   developing  widening  cracks  appear;  underground  utility  lines   break § Flow  –  when  there  is  water  or  ice  to  lubricate  the  movement  of  slope  material • Debris  (Mud  flow)  –  movements  of  fluidised  soil  and  other  material   acing  in  a  viscos  mass o occurs  when  there  is  lo ose  slope  material  that  becomes   saturated   o high  water  content  –  fast  moving;  generally  follow  stream   channels;  deadly § creep  –  the  imperceptibly  slow  down-­‐slope  movement  of  material;  usually  has   to  do  with  freezing  and  thawing  of  the  soil;  can  be  indicated   by  tilted  fence   posts   • soilfluction  –  involves  the  freezing  and  thawing  of  soil  above  the   permafrost,  causing  the  slope  to  sag  downslope   § Other triggers of mast wasting: events ice wedging; biological activity (human pushing a rock down a hill); shocks (like an earthquake) • Slope modification – modification of a slop by either humans or by natural cause can result in changing the slope angle so that it is no longer at the angle of repose; a mass wasting event can then restore the slope to its angle of repose • Undercutting – streams eroding their banks or surf action can undercut a slope making it unstable • Overloading – involves an increase in weight which may increase the shear stress on the slope or may increase the water pressure and decrease friction causing slope failure; this factor is almost always the result of human activity including the weight of buildings, or things like dumping, filling or piling up material • Removal of vegetation – can cause erosion of soil more easily • Exceptional precipitation – heavy rains can saturate regolith reducing grain to grain contact and reducing the angel of repose, thus triggering a mass wasting event Fluvial processes • Running  water  over  the  land   • Fluvial  -­‐  system  is  powered  by  conversion  of  the  potential  energy  of  sol ar  radiation  and  gravity  to   kinetic  energy  of  motion  and  heat;  most  energy  is  lost  to  friction  and  turbulence,  but  small   fraction  is  converted  to  mechanical  work  of  erosion  and  transportation   o Contributes  more  to  shaping  landforms  than  all  the  other  externa l  components  combined   • Agents  of  continental  denudation   o Rivers  85-­‐90%   o Glaciers  7%   o Waves  2%   o Wind  1%   • Stream  -­‐  a  long  narrow  body  of  water  that  flows  in  a  trench  like  depression  (channel)  under  the   force  of  gravity   • Classical  Fluvial  Classification  Systems   o By  constancy  of  flow   • Perennial  streams  -­‐  constant  flow;  streams  that  we  see  in  mid  latitudes;  base  flow  is   provided  by  ground  water  seepage  into  the  channel   • Intermittent  (seasonal)  streams  -­‐streams  which  only  flow  during  wetter  times  of  the   year     • Ephermal  Streams  -­‐  a  stream  that  carries  water  only  during  and  immediately  after   periods  of  rainfall  or  snowmelt     • The  stream  system   o Drainage  basin  /  watershed   -­‐  an  area  of  land  that  contains  a  common  set  of  streams  and   rivers  that  all  drain  into  a  singer  larger  body  of  water,  such  as  a  larger  river,  lake  or  ocean   o Drainage  divide  -­‐  represents  the  boundary  between  adjacent  drainage  basins  and   determines  into  which  basin  precipitation  flows   o Tributary  systems  -­‐  are  small  streams  that  enter  into  the  main  stream   o Endorheic  basins  do  not  drain  into  the  ocean   • Stream  characteristics   o Channel  slope  or  gradient   -­‐  the  difference  in  elevation  between  two  points  on  a  stream   divided  by  the  distance  between  them  measured  along  the  stream  channel   o Flow  velocity  -­‐  how  fast  the  water  is  movin g  through  a  cross  section;  determined  by  the   balance  between  the  down  slope  gravitational  stress  as  a  result  of  the  slope  of  a  stream,   and  the  loss  or  expenditure  of  energy  in  the  overcoming  the  frictional  resistance  of  the   channel  bed  and  side   o Stream  discharge  (Q)  -­‐  the  volume  of  water  passing  through  a  particular  cross  section  in  a   unit  of  time,  measured  in  units  like  cubic  meters  per  second  or  cubic  feet  per  second     • Q  =  A*V   § A  -­‐  cross  sectional  area;  V  -­‐  velocity   • The  work  of  streams   o Erosion  -­‐  the  group  of  processes  whereby  earth  material  is  loosened  or  dissolved  and   removed  from  any  part  of  the  earth's  surface;  stream  erosion  is  the  detachment  of  material   from  bed  or  sides  of  the  channel   • Erosional  landforms  -­‐  landforms  shaped  by  removal  of  regolith  or  bedr ock  by  erosion   o Transportation  -­‐  once  material  is  detached  from  the  channel  it  can  be  transported;   transportation  is  the  movement  of  earth  material,  in  this  case,  by  water     o Deposition  -­‐  the  laying  down  of  potential  rock  forming  material  in  the  form  of  sedim ents     • Depositional  landforms   -­‐  landforms  made  by  the  deposition  of  sediment   o Hydraulic  action  -­‐  the  impact  of  water  on  the  sides  and  bed  of  a  channel;  it  dislodges   unconsolidated  materials  and  makes  them  available  for  transport   o Abrasion  -­‐  the  mechanical  wearing  down  of  rock  by  the  rock  fragments  that  are  being   transported  by  the  stream   o Corrosion  -­‐  the  chemical  reaction  of  moving  water  with  the  material  on  the  stream  bed   o Rainsplash  erosion    the  process  of  disturbing  the  soil  surface  by  the  direct  force  of  fal ling   rain  drops   o Overland  flow  -­‐  unconfined  flow  of  water  running  across  the  surface  in  very  shallow  depths;   occurs  on  relatively  smooth  slopes   • Rill  erosion  -­‐  If  there  are  small  irregularities  at  the  surface,  the  water  tends  to   concentrate  in  small  channels  called  Rills.  Because  water  is  confined  it  moves  much   faster   § Rill  erosion  is  the  removal  of  material  by  concentrated  erosion  running  through   little  streams   o Gullies  -­‐  steep  sided  trenches  formed  by  the  coalescence  of  many  rills     o Ravine  -­‐  a  deep  narrow  steep-­‐sided  valley  formed  by  running  water   o Progression  of  erosional  landforms  associated  with  streams   • Rills  -­‐-­‐>  gullies  -­‐-­‐>    ravines  -­‐-­‐>  valleys   o The  base  level  of  a  stream  is  defined  as  the  lowest  level  to  which  a  stream  can  erode  its   channel;  lowest  level  at  which  erosion  is  impossible  (aka  like  the  mouth  of  the  river  where  it   meets  the  ocean)   • For  most  streams,  base  level  is  sea  level  (Absolute  (ultimate)  base  level)   • Variations  in  bedrock  and  topography  will  often  result  in  a  temporary  base  level  (local   base  level)   • Examples  of  local  base  levels:  lakes,  larger  streams,  resistant  rock   • Sediment  transport  in  a  stream   -­‐  the  material  transported  through  a  stream  is  called  the  stream   load:   o Dissolved  -­‐  part  of  the  fluid;  comes  from  groundwater  seepage  into  the  stream;   also  comes   from  the  solution  of  materials  that  line  the  channel;  particular  important  in  limestone  areas   o Suspended  -­‐  comprised  of  sediment  and  transported  through  the  stream;  composed  of  silt   and  clay  particles  suspended  by  flow   o Bed  (or  traction)  load   -­‐  that  which  is  moved  across  the  bed  of  the  channel   • Can  be  transported  by   § Traction  -­‐  scooting  and  rolling  of  particles  along  the  bed   § Saltation  -­‐  a  bouncing  like  movement     • Stream  competence  -­‐  the  size  of  the  largest  particles  a  stream  can  move;  competence  is  ex pressed   in  terms  of  mass;  it  is  a  function  of  stream  velocity   • Steam  capacity  -­‐  the  total  sediment  load  a  stream  can  move  or  transport  in  a  given  length  of  time;   expressed  in  terms  of  mass  per  time;  it  is  a  function  of  stream  discharge   • The  functions  of  velocity   o Deposition  in  regards  to  velocity -­‐  as  velocity  and  discharge  decreases,  the  ability  of  the   stream  to  move  sediment  through  it  decreases,  the  heaviest  particles  deposit  on  the  bed   first,  with  the  smaller  and  lighter  particles  transported  much  further  b efore  accumulating   • Alluvium  -­‐  materials  deposited  by  streams   o Erosion  -­‐  if  velocity  goes  up  then  rate  of  erosion  goes  up   o Transportation  -­‐  stream  capacity  (the  total  sediment  load  a  stream  can  move  or  transport)  is   a  function  of  stream  discharge  (Q   -­‐  the  volume  of  water  passing  through  a  particular  cross   section  in  a  unit  of  time);  if  stream  discharge,  Q,  is  increasing,  then  so  is  stream  capacity   • AKA:  the  more  water  passing  in  a  rover,  then  the  more  sediment  load  a  stream  can   move  and  transport   o Streams  can  undergo  substantial  changes  in  their  geometry  in  response  to  changes  in  the   velocity,  discharge  and


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All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.