GEOLOGY: UNIT 1

GEOLOGY: UNIT 1

1. THE EARTH AND ITS SPHERES

   • GEOSPHERE
     • PROCESSES TO GENERATE HEAT
       • CONTINUOUS IMPACTS OF PLANETESIMAL DURING ACCRETION
       • DECACY OF RADIACTIVE ISOTOPES
         • POTTASIUM
         • URANIUM
       • DIFFERENTIATION OF MATERIALS, DUE TO GRAVITY INTO 3 LAYERS
         • CRUST
           • THIN TOP LAYER FORMED OF ALUMINIUM SILICATES
         • MANTLE
           • LAYER OF IRON AND MAGNESIUM SILICATES FLOATING ON THE CORE
         • CORE
           • METALIC CENTRE FORMED OF THE HEAVIEST ELEMENTS
   • ATMOSPHERE
     • ORIGIN
       • HYDROGEN AND HELIUM ESCAPED INTO THE SPACE. CARBON DIOXIDE AND WATER VAPOUR WERE TRAPPED IN THE CRUST. THEY ESCAPE THROUGH FISSURES. CAUSING INTENSE VOLCANIC ACTIVITY
   • HYDROSPHERE
     • WATER IN THE ATM CONDENSE. HEAVY RAINFALL FLOOD THE DEPRESSIONS ON THE SOLID SURFACE
   • BIOSPHERE
     • LIFE ON THE EARTH WAS POSSIBLE BY TWO FACTORS
       • DISTANCE BETWEEN THE EARTH AND THE SUN
       • PHYSICAL AND CHEMICAL CONDITIONS ON THE EARTH
         • TEMPERATURE
         • PRESSENCE OF LIQUID WATER
     • BIOLOGICAL ACTIVITY HAS INFLUENCED
       • OXIGENATION OF THE ATMOSPHERE
         • PLANTS
         • BACTERIA
         • ALGAE
       • FORMATION OF THE SOIL
       • CREATION OF THICK BANDS OF ROCK
         • LIMESTONE

2. INTERNAL STRUCTURE OF THE EARTH

   • GEOCHEMICAL MODEL
     • BASED CHEMICAL COMPOSITION OF THE EARTH
     • CRUST
       • CONTINENTAL CRUST
       • OCEANIC CRUST
     • MANTLE
     • CORE
     • DISCONTINUITIES
       • MOHOROVICIC
         • CRUST - MANTLE
       • GUTEMBERG
         • MANTLE - CORE
       • REPETTI
         • UPPER MANTLE - LOWER MANTLE
       • LEHMAN
         • OUTER CORE - INNER CORE
   • GEODYNAMIC MODEL
     • LITHOSPHERE
       • DIVIDED IN PLATES (INMEDIATE UPPER MANTLE)
     • ASTENOSPHERE
       • NO CONTINUOUS LAYER. (UPPER MANTLE)
     • MESOSPHERE
       • SOLID BUT FLOWS SLOWLY (LOWER MANTLE)
     • OUTTER CORE
       • HEAT IN THE SOLID INNER CORE SPREADS TO THE LIQUID OUTER CORE. GENERATES CONVECTION CURRENTS
     • INNER CORE
       • PUSH HEAT OUT OF THE CORE INTO THE D’’-LAYER. GENERATES EARTH`S MAGNETIC FIELD
     • BASED ON
       • PHISICAL STATE OF LAYERS
         • PLASTICITY, RIGIDITY AND DENSITY
       • MECHANICAL PROPERTIES OF THE LAYERS (HOW THEY RESPOND TO CHANGES IN PRESSURE AND TEMPERATURE)
     • D'' LAYER
       • FROM THE OUTER CORE ACCUMULATES HEAT AND HOT MAGMA ESCAPES FROM THIS LAYER AS MANTLE PLUMES THET BREAK LITHOSPHERE CREATING HOTSPOTS

3. CHEMICAL COMPOSITION OF THE EARTH

   • SEISMIC WAVES ARE USED TO UNDERSTAND THE INTERIOR OF THE EARTH
   • EARTHQUAKES
     • HYPOCENTRE IS THE POINT WITHIN THE EARTH WHERE AN EARTHQUAKE ORIGINATES. FROM HERE THE VIBRATIONS TRAVEL THROUGH THE INNER LAYERS OF THE EARTH AS SEISMIC WAVES
       • P-WAVES
         • PRIMARY WAVES
         • TRAVEL THROUGH SOLID AND LIQUID
         • AS IT TRAVELS IT SHAKES THE GROUND BACKWARDS AND FORDWARS
         • FASTEST WAVES AND THE FIRST TO REACH THE SISMOGRAPH
       • S-WAVES
         • SECONDARY WAVES
         • TRAVEL THOUGH SOLID BUT NOT IN LIQUID
         • THE OSCILLATIONS ARE AT RIGHT ANGELS TO THE DIRECTION OF THE TRAVEL
         • SLOWER THAT P-WAVES
       • THE POINT OF THE SURFACE THAT THE WAVES REACH FIRST IS CALLED EPICENTRE

4. THE INTERNAL ENGINE OF THE EARTH

   • HEAT FLOW
     • GRATER IN DEPHT
     • HIGHER TEMPERATURE (GEOTHERMAL GRADIENT)
       • AVERAGE GEOTHERMAL GRADIENT IN THE CRUST IS 3ºC PER 100M
   • CONVECTION CURRENTS
     • INTERNAL ENGINES DIVIDING THE INTERNAL DYNAMICS OF THE EARTH
     • LITHOSPHERIC PLATES MOVE HORIZONTALLY
       • ALFRES WAGEBER - THEORY OF CONTINENTAL DRIFT
       • 300 M Y - PLATES WERE JOINED (PANGEA)
       • CONTINENT BEGAN TO SEPARATE
         • EVIDENCES
           • GEOLOGICAL EVIDENCE
             • SOME CONTINENTS SEEMED TO FIT TOGETHER
           • PALEOCLIMATIC EVIDENCE
             • GLACIATION THAT OCCURED 300 MY AGO CURRENTLY SEPARATED AREAS
           • PALEONTOLOGICAL EVIDENCE
             • FOSILS OF VERY SIMILSR ANIMALS WERE FOUND ON DIFFERENT CONTINENTS
             • THE ONLY EXPLANATION WAS THAT THOSE CONTINENTS HAD BEEN VERY CLOSE TO EACH OTHER IN THE PAST
   • PLATES TECTONICS
     • THEORY - WILSON
       • PRINCIPLES
         • LITHOSPHERE IS DIVIDED INTO PLATES. PLATES ARE SEPARATED BY UNSTABLE BOUNDARIES CHARACTERISED BY INTENSE SEISMIC AND VOLCANIC ACTIVITY
         • OCEANIC LITHOSPHERE IS THINNER AND DENSER THAN CONTINENTAL LITHOSPHERE. GENERATED AT 'MID OCEAN RIDGETS'. AT THE SAME TIME IT IS DESTROYED IN 'OCEANIC TRENCHES OR SUBDACTION ZONES'
         • GRAVITY AND THE INTERNAL HEAT OF THE EARTH GENERATE CONVECTION CURRENTS THAT MOVE TECTONIC PLATES
     • OCEANIC PLATES
       • OCEANIC LITHOSPHERE
     • CONTINENTAL PLATES
       • MIXTURE OF CONTINENTAL AND OCEANIC LITHOSPHERE
   • BOUNDARIES
     • CONVERGENT
       • EVENTS
         • CONTINENTAL COLLIDE
         • OCEANIC LITHOSPHERE IS DESTROYED
       • GEOLOGICAL STRUCTURE
         • OROGENS / OROGENIC BELTS: MOUNTAIN RANGES
         • SUBDACTION ZONES
     • DIVERGENT
       • EVENTS
         • OCEANIC LITHPHERE IS CREATED
       • GEOLOGICAL STRUCTURE
         • MID-OCEAN RIDGES
     • TRANSFORM
       • EVENTS
         • PLATES SLIDE PAST EACH OTHER
       • GEOLOGICAL STRUCTURE
         • TRANSFORM FAULTS