UNIT 2 THE EARTH´S PHYSICAL CHARACTERISTICS. PART 1: RELIEF

1. UNIT 2 THE EARTH´S PHYSICAL CHARACTERISTICS. PART 1: RELIEF

2. IN THIS UNIT YOU WILL … LEARN ABOUT THE STRUCTURE OF THE EARTH AND HOW IT WAS FORMED … LEARN ABOUT THE FORCES THAT SHAPE THE EARTH´S RELIEF IDENTIFY THE MAIN FEATURES OF THE EARTH´S RELIEF LEARN ABOUT EARTHQUAKES AND VOLCANOES

3. THE EARTH´S SURFACE THE EARTH´S SURFACE IS MADE UP OF WATER AND LAND CONTINENTS OCEANS ARE BODIES OF SALTWATER THAT COVER 71% OF THE EARTH´S SURFACE THERE IS SUBMERGED LAND BENEATH THE OCEANS ARE LARGE AREAS OF LAND THAT COVER 29% OF THE EARTH´S SURFACE WE CLASSIFY MATERIAL THAT MAKES UP THE EARTH´S SURFACE IN DIFFERENT ZONES LITHOSPHERE HYDROSPHERE ATMOSPHERE BIOSPHERE IS THE SOLID, ROCKY COVERING OF THE EARTH´S SURFACE IS ALL THE WATER ON EARTH, INCLUDING OCEANS, SEAS, LAKES, RIVERES AND UNDERGROUND WATER IS A LAYER OF GASES, INCLUDING NITROGEN AND OXYGEN, THAT SURROUNDS THE EARTH IS THE THIN LAYER OF ATMOSPHERE, EARTH AND WATER WHERE LIFE EXISTS

4. OCEANS AND CONTINENTS

5. THE SCIENCE OF GEOLOGY IS THE STUDY OF ALL THE MATERIALS THAT MAKE UP THE SOLID PART OF THE EARTH GEOLOGISTS EXAMINE ROCKS TO FIND EVIDENCE OF ALL THE CHANGES THAT HAVE OCCURRED THEY ALSO STUDY FOSSILS, WHICH ARE THE REMAINS OF LIVING THINGS PRESERVED IN THE ROCKS BOTH ROCKS AND FOSSILS ARE FOUND IN LAYERS CALLED STRATA. THESE ARE FORMED OF SEDIMENTARY ROCKS, WHICH GRADUALLY ACCUMULATE AT THE EARTH´S SURFACE THE OLDEST MATERIALS ARE FOUND IN THE LOWEST STRATA 6 minutes video aboutthescience of Geology

7. STRUCTURE OF THE EARTH THE EARTH IS MADE UP OF 3 MAIN LAYERS: • CORE • MANTLE • CRUST Mantle Outer core Inner core Crust

8. THE CRUST This is where we live! The Earth’s crust is made of CONTINENTAL CRUST OCEANIC CRUST • thin (~7 km) • dense (sinks under continental crust) • young • thick (10-70km) • buoyant (less dense than oceanic crust) • mostly old

9. What is Plate Tectonics?

10. IF YOU LOOK AT A MAP OF THE WORLD, YOU MAY NOTICE THAT SOME OF THE CONTINENTS COULD FIT TOGETHER LIKE PIECES OF A PUZZLE. WHY?

11. CONTINENTAL DRIFT THE SINGLE SUPERCONTINENT THAT SCIENTISTS CALL PANGEA EXISTED ABOUT 200 MILLION YEARS AGO OVER TIME, IT BROKE UP INTO SEPARATE CONTINENTS THAT GRADUALLY MOVED APART THIS THEORY IS CALLED CONTINENTAL DRIFT THE BOUNDARIES BETWEEN THE PLATES ARE VERY UNSTABLE. WHEN PRESSURE BUILDS UP UNDER THE EARTH´S SURFACE IT CAUSES EARTHQUAKES AND VOLCANIC ERUPTIONS ALONG THESE BOUNDARIES THE EARTH´S CRUST IS MADE UP OF TECTONIC PLATES THAT MOVE CONTINOUSLY THERE ARE SEVEN OR EIGHT MAJOR PLATES AND SEVERAL OTHER MINOR ONES THESE PLATES SLIDE AGAINST EACH OTHER OR MOVE APART

12. Interesting video (5:17) abouttectonicplates 3:19 m long video aboutthe continental drift. Music , images and texts

13. World Plates

14. True or False: The Earth’s surface has stayed the same for thousands of years False The Earth’s surface is always changing!

15. RELIEF FORMATION AND TRANSFORMATION RELIEF IS THE SHAPE OF THE EARTH´S SURFACE. IT IS THE RESULT OF INTERNAL FORCES THAT FORM IT AND EXTERNAL FORCES THAT TRANSFORM IT • RELIEF FORMATION • RELIEF TRANSFORMATION INTERNAL FORCES EXTERNAL FORCES THESE FORCES MAY MOVE, RAISE OR SINK LAND ON THE EARTH´S SURFACE. THEY ACT THROUGH CONTINUAL PRESSURES AND THROUGH EARTHQUAKES AND VOLCANOES IN ADDITION TO INTERNAL FORCES DEEP INSIDE THE EARTH, RELIEF IS ALSO SHAPED BY EXTERNAL AGENTS ON THE EARTH´S SURFACE • OROGENY • EARTHQUAKES • VOLCANOES • ATMOSPHERE • WATER • LIVING THINGS

16. INTERNAL FORCES

17. OROGENY: PRESSURES ON THE EARTH´S SURFACE THERE ARE CONTINUAL PRESSURES ON THE EARTH´S SURFACE NEAR THE BOUNDERIES OF TECTONIC PLATES. FOLDS AND FAULSTS ARE CREATED AS A RESULT OF THESE PRESSURES FOLDS FAULTS FAULTS ARE BREAKS IN ROCK LAYERS WHERE THE ROCK IS TOO HARD TO BEND FOLDS ARE DEFORMATIONS OF THE EARTH´S SURFACE WHERE ROCK LAYERS BEND

19. EARTHQUAKES EARTHQUAKES ARE CAUSED WHEN THE EARTH´S CRUST IS SHAKEN EARTHQUAKES GENERALLY OCCUR ALONG THE BOUNDARIES OF TECTONIC PLATES, WHERE THE PLATES SLIDE AGAINST EACH OTHER. ENERGY IS RELEASED IN SEISMIC WAVES FROM A FOCUS, OR HYPOCENTRE, INSIDE THE EARTH EARTHQUAKES ON THE OCEAN FLOOR CAUSE TSUNAMIS, WHICH ARE HUGE TIDAL WAVES THAT CAUSE GREAT DESTRUCTION IN COASTAL AREAS THE EPICENTRE IS THE POINT ON THE EARTH´S SURFACE THAT IS DIRECTLY ABOVE THE FOCUS. THIS IS WHERE THE EARTHQUAKE IS AT ITS STRONGEST ACTIVITIES WHAT IS THE FOCUS OR HYPOCENTRE OF AN EARTHQUAKE? WHAT IS THE EPICENTRE?

22. VOLCANOES A VOLCANO IS A CRACK IN THE EARTH´S CRUST HOT LIQUID ROCK, CALLED MAGMA, RISES TO THE SURFACE WHEN IT ERUPTS. ROCKS, ASH AND GASES ARE EJECTED THROUGH ITS MAIN CHANNEL, OR VENT, AND MATERIAL IS DEPOSITED ALL AROUND THE CRATER DURING THE ERUPTION, HOT LIQUID LAVA FLOWS OUT BEFORE IT COOLS AND BECOMES SOLID. TOGETHER WITH SOLID ROCKS, IT ACCUMULATES AROUND THE CRATER AND FORMS A CONE ACTIVITIES COPY THE DIAGRAM OF THE VOLCANO THAT IS IN YOUR BOOK (28) WHAT IS THE RICHTER SCALE? WHAT DO THE DIFFERENT NUMBERS ON THE SCALE MEAN?

24. EXTERNAL AGENTS OF RELIEF

25. EROSION PROCESS

26. PROCESS OF EROSION EROSION SEDIMENTATION TRANSPORTATION

27. WEATHERING ROCKS ARE EXPOSED TO AIR, WATER CHANGES IN TEMPERATURE AND VEGETATION, BECOME VULNERABLE TO WEATHERING. WEATHERING INCLUDES THE BREAKING UP (DISINTEGRATION) AND DECAY (DECOMPOSITION) OF ROCKS IN PLACES WHERE THEY FORMED. UNLIKE EROSION, WEATHERING NEED NOT INVOLVE THE MOVEMENT OF MATERIAL • THERE ARE THREE MAIN TYPES • Itiswhen rock isbrokenintosmollarpiecesbyphisicalprocesses. Itismostlikelytooccur in areas of bare rock wherethereis no vegetationtoprotectthe rock from extremes of weather: • Freeze-thaworfrostshattering • Exfoliationoronionweathering. Itiswhenwater and air activatechemicalchangesthat cause rock torot and decay. Chemicalreactions are greattwheretheclimateisverywarm and wet. Limestonesolutionisanexample of chemicalweathering. Itoccurswheneithertreerootspenetrate and widencracks in a rock (phisical) oracids, releasedbydecayingvegetation, attackthe rock (chemical). • PHISICAL • WEATHERING • BIOLOGICAL • WEATHERING • CHEMICAL • WEATHERING

28. EXFOLIATION OR ONION WEATHERING OCCURS IN VERY WARM CLIMATES WHERE EXPOSED ROCK IS REPEATEDLY HEATED AND COOLED. DURING THE DAY, THE SURFACE LAYERS OF ROCK ARE HEATED AND EXPAND. AT NIGHT, THEY COOL AND CONTRACT. IN TIME THIS CAUSES THE OUTER LAYERS TO PEEL OFF, LIKE THOSE OF AN ONION, TO LEAVE STEEP-SIDED, ROUNDED HILLS AND BOULDERS. FREEZE-THAW OR FROST SHATTERING IS COMMON WHEN TEMPERATURE IS AROUND FREEZING POINT AND WHERE EXPOSED ROCKS CONTAINS MANY CRACKS . WATER, ENTERING CRACKS DURING THE DAY, FREEZES DURING COLDER NIGHTS. AS THE WATER TURNS TO ICE IT EXPANDS AND, DUE TO THE ICREASE IN PRESSURE, CAUSES CRACKS TO WIDEN. WHEN THE TEMPERATURE RISES, THE ICE MELTS AND PRESSURE IS RELEASED. THIS REPEATED PROCESS WEAKENS THE ROCK UNTIL PIECES BREAK OFF.. • PHISICAL WEATHERING

29. THE EARTH´S RELIEF OCEANIC CONTINENTAL SIMPLE LANDFORMS ON THE CONTINENTAL RELIEF LARGE RELIEF FORMS LANDFORMS OF COASTAL RELIEF • The continental Shelf • The continental slope • Abyssalplains: • Oceanicridges • OceanicTrenches • Plains • Plateaus • Mountains • Depressions • TheShields • - Sedimentary • basins • Young mountains • Capes orheadlands • Gulfsorbays • Peninsulas • Estuaries • Deltas • Isthmus • Fjords • Islands • Archipelagos • Beaches • Cliffs Pages 26-27

30. CONTINENTAL RELIEF SIMPLE LANDFORMS ON THE CONTINENTAL RELIEF DEPRESSIONS MOUNTAINS PLATEAUS PLAINS ELEVATIONS OF TERRAIN ABOVE THE SURROUNDING LAND WITH STEEP SLOPES PLAINS HIGHER THAN 200 METERS ABOVE SEA LEVEL SUNKEN OR DEPRESSED AREAS BELOW THE SURROUNDING AREAS LARGE AREAS OF FLAT TERRAIN

31. CONTINENTAL RELIEF LARGE RELIEF FORMS YOUNG MOUNTAINS THE SHIELDS SEDIMENTARY BASINS Steep, youngermountains at high altitudes Largedepressedareasthatwefind in theshields. Theoldestparts of continents.

32. LANDFORMS OF COASTAL RELIEF CAPE OR HEADLAND PENINSULA

33. LANDFORMS OF COASTAL RELIEF ESTUARY ISLAND DELTA ARCHIPELAGO

34. LANDFORMS OF COASTAL RELIEF FJORD BEACH CLIFF RIA

35. ARCHIPELAGO BAY ISLAND GULF STRAIT BEACH CCAPE PENINSULA “CALA” POINT CLIFF ISTHMUS

37. YOUNG MOUNTAIN BASIN OR DEPRESSION BEACH OLD MOUNTAIN CAPE GULF CLIFF RIA BAY LAGOON ITHSMUS DELTA PENINSULA ARCHIPELAGO

38. OCEANIC LANDFORMS • OCEANIC LANDFORMS CONTINENTAL SLOPE CONTINENTAL PLATFORM OR SHELF ISLANDS OF VOLCANIC ORIGIN OCEANIC RIDGE ABYSSAL PLAIN OCEANIC TRENCH RIFT

39. ANY QUESTIONS?