MARINE GEOLOGY & GEOGRAPHY

MARINE GEOLOGY MARINE GEOLOGY & GEOGRAPHY Marine Geology 4 LAYERS OF THE EARTH CRUST THICKNESS: VARIES BETWEEN OCEAN & CONTINENTS 5-40 KM STATE: SOLID ELEMENTS: SILICON, ALUMINUM, CALCIUM, SODIUM, POTASSIUM LOCATION OF THE EARTH S PLATES FLOATS ON THE LAYER BENEATH LEAST DENSE LAYER CONTINENTAL AND OCEANIC CRUSTS LITHOSPHERE= CRUSTS + UPPER MOST PART OF MANTLE Layers of the Earth Layers of the Earth

MANTLE THICKNESS: 2,750 KM STATE: PLASTIC- ABILITY OF A SOLID TO FLOW ELEMENTS: SILICON, OXYGEN, MAGNESIUM, IRON, ALUMINUM, CALCIUM CONVECTION CURRENTS DUE TO UNEVEN HEATING IN THIS LAYER CAUSE THE EARTH S PLATES TO MOVE ASTHENOSPHERE AND MESOSPHERE OUTER CORE THICKNESS: 2,260 KM STATE: LIQUID ELEMENTS: IRON AND NICKEL EXTREMELY HOT RESPONSIBLE FOR OUR MAGNETIC FIELD Layers of the Earth Layers of the Earth INNER CORE THICKNESS: 1,228 KM STATE: SOLID TEMPERATURE AND PRESSURE IS SO GREAT, THAT THE METALS ARE SQUEEZED TOGETHER AND CANNOT MOVE. ELEMENTS: IRON AND NICKEL ALFRED WEGENER PLATE TECTONICS KNOWN FOR HIS THEORY ON CONTINENTAL DRIFT 1915- PUBLISHED THE ORIGINS OF CONTINENTS AND OCEANS CONTINENTAL DRIFT SUPERCONTINENT- PANGEA Layers of the Earth

PLATE TECTONICS CONTINENTAL DRIFT SUPPORTED BY: IDENTICAL FOSSILS FOUND ON DIFFERENT CONTINENTS CONTINENTS FIT TOGETHER LIKE PUZZLE PIECES GEOLOGICAL FEATURES MATCH TOGETHER COAL DEPOSITS IN EUROPE AND N. AMERICA MOUNTAIN RANGES IN AFRICA AND S. AMERICA PLATE TECTONICS PLATE BOUNDARIES SO WHAT CAUSED THE PLATES TO MOVE APART? THE CRUST IS MADE UP OF SEVERAL DIFFERENT PLATES THAT CAN MOVE INDEPENDENTLY OF ONE ANOTHER CONVECTION CURRENTS IN THE MANTLE PUSH/PULL THE PLATES

DIVERGENT BOUNDARIES OCEAN- (SEA-FLOOR SPREADING) TWO PLATES MOVE AWAY FROM EACH OTHER MAGMA MOVES UP TO FILL THE SPACE CREATING NEW ROCK FORMS OCEAN RIDGES CONTINENTAL- FORMS RIFT VALLEYS CONVERGENT BOUNDARIES PLATES MOVE TOWARDS EACH OTHER AKA: SUBDUCTION ZONES- AREAS OF PLATE DESTRUCTION 3 TYPES: OCEANIC- OCEANIC OCEANIC- CONTINENTAL CONTINENTAL- CONTINENTAL FORMS: TRENCHES ISLAND ARCS CONVERGENT: OCEANIC- OCEANIC CONVERGENT: OCEANIC- CONTINENTAL FORMS: TRENCHES VOLCANIC ARCS

FORMS: CONVERGENT: CONTINENTAL- CONTINENTAL MOUNTAINS OCCURS AS TWO PLATES SLIDE PAST EACH OTHER NO PLATE DESTRUCTION EARTHQUAKES ARE COMMON DUE TO FRICTION OFFSETS GEOLOGIC FEATURES TRANSFORM BOUNDARIES PLATE BOUNDARIES OTHER CIRCUMSTANCES SOME AREAS HAVE PLUMES OF MAGMA CLOSE TO THE SURFACE AKA: HOT-SPOTS RESPONSIBLE FOR SEVERAL ISLAND CHAINS INCLUDING HAWAII MAGMA RISES TO THE SURFACE AT VOLCANOES CREATING NEW ISLANDS

11/12/2015 OTHER CIRCUMSTANCES BATHYMETRY HYDROTHERMAL VENTS SEA WATER SEEPS THROUGH CRACKS IN THE CRUST NEAR PLATE BOUNDARIES IT GETS HEATED CLOSE TO MAGMA CHAMBERS RUSHES BACK TO THE CRUST CARRYING NUTRIENTS Bathymetry BATHYMETRY THE UNDERWATER EQUIVALENT TO TOPOGRAPHY BATHYMETRY INFORMATION COMES FROM: ECHOSOUNDERS (SONAR) THE STUDY OF WATER DEPTH BOUNCE SOUND WAVES OFF OF OCEAN FLOOR A BATHYMETRIC MAP SHOWS FLOOR RELIEF OR TERRAIN AS CONTOUR LINES MAP THE DISTANCE FROM SEA LEVEL TO FLOOR Bathymetry CURRENT SONAR READS WIDE BANDS SIMULTANEOUSLY (MULTIBEAM)) Bathymetry

INFORMATION COMES FROM: SATELLITES MEASURE SLIGHT VARIATIONS IN SEA LEVEL SEA LEVEL IS HIGHER ABOVE MOUNTAINS AND RIDGES THAN ABYSSAL PLAINS LIDAR (LASERS) BATHYMETRY WHO COLLECTS THE DATA? ARMY CORPS OF ENGINEERS INLAND WATERWAYS, RIVERS, LAKES NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (NOAA) OCEANS, SEAS, GULFS BATHYMETRY Bathymetry Bathymetry OCEAN FLOOR FEATURES CONTINENTAL MARGIN TWO MAIN DIVISIONS: CONTINENTAL MARGIN CONTINENTAL SHELF CONTINENTAL SLOPE CONTINENTAL RISE OCEAN BASIN PLAINS TRENCHES RIDGES & RISES SEA MOUNTS & GUYOUTS CORAL REEFS & ATOLLS CONTINENTAL SHELF SUBMERGED PART OF CONTINENT GENTLE SLOPE TO OCEAN BASIN

11/12/2015 CONTINENTAL MARGIN CONTINENTAL SLOPE EXTENDS FROM SHELF BREAK TO RISE BOUNDARY BETWEEN CONTINENTAL AND OCEANIC CRUST CONTINENTAL MARGIN CONTINENTAL SLOPE SUBMARINE CANYONS FORM FROM RIVER EROSION TURBIDITY CURRENTS STEEP SLOPE CONTAINS SUBMARINE CANYONS CONTINENTAL MARGIN CONTINENTAL RISE CONTINENTAL MARGIN ACTIVE: FOUND AT BASE OF SLOPE CONVERGENT PLATE BOUNDARIES FORMED FROM SEDIMENT DEPOSITION NARROW MARGIN/ SHELF GENTLE SLOPE FROM SEA FLOOR TO SLOPE TRENCHES TECTONICALLY ACTIVE PASSIVE: NO PLATE BOUNDARY WIDE MARGIN/ SHELF THICK SEDIMENT LITTLE TECTONIC ACTIVITY

OCEAN BASIN OCEAN BASIN OCEAN BASIN FLOOR: ABOUT 30% EARTH S SURFACE BEGINS AT THE CONTINENTAL RISE MOSTLY ABYSSAL PLAINS WITH OTHER FEATURES ABYSSAL PLAIN FLAT DEEP OCEAN FLOOR MAY BE MORE THAN 2 MILES DEEP THICK SEDIMENT ACCUMULATION TRENCHES OCCUR AT SUBDUCTION ZONES OCEANIC CRUST IS FORCED INTO MANTLE ASSOCIATED WITH EARTHQUAKES DEEPEST= MARIANA S TRENCH 11000+ M LONGEST= PERU-CHILE TRENCH 5900+ KM OCEAN BASIN RIDGES & RISES OCEAN BASIN UNDERWATER MOUNTAIN RANGES FORMED BY SEA-FLOOR SPREADING CONTAIN CENTRAL RIFT VALLEY RIDGES RISES STEEP SLOPE (SLOW MOVING PLATES) GENTLE SLOPE (FAST MOVING PLATES)

SEAMOUNTS & GUYOUTS UNDERWATER VOLCANOES NEAR RIDGES AND OVER HOT SPOTS MAY EMERGE AS ISLANDS SEAMOUNTS- STEEP SLOPE JUTTING UP FROM SEA FLOOR GUYOUTS- FLAT TOP DUE TO EROSION OCEAN BASIN CORAL REEFS & ATOLLS OCEAN BASIN FORM AROUND VOLCANIC ISLANDS AND SEAMOUNTS ONLY FORM IN SHALLOW WATERS DORMANT VOLCANOES/ SEAMOUNTS ERODE AWAY AND BECOME A BARRIER REEF AND EVENTUALLY AN ATOLL BARRIER REEF- ACTIVELY GROWING CORAL REEF SURROUNDING A RECEEDING ISLAND ATOLL- SHALLOW LAGOON SURROUNDED BY MATURE CORAL REEF OCEANS OF THE WORLD REVIEW AVERAGE DEPTH 2.3 MILES SALINITY= 35 PPT (3.5% SALT) MAJORITY IS <39 F (4 C) MAJORITY IS DARK CONTAINS >97% OF THE EARTH S WATER

OCEANS OF THE WORLD PACIFIC LARGEST AVG. DEPTH 14,500 FT BASIN COVERS 33% OF THE EARTHS SURFACE HOLDS 52% OF THE EARTH S WATER RING OF FIRE HIGHLY TECTONICALLY ACTIVE REGION 90% OF WORLD S EARTHQUAKES MARIANA TRENCH ATLANTIC 2 ND LARGEST AVG DEPTH 12,500 FT MANY SHALLOW MARINAL SEAS LARGE MARGINS MID-ATLANTIC RIDGE MOSTLY UNDERWATER MOUNTAIN RANGE SOME PEAKS RISE ABOVE SEA LEVEL TO FORM ISLANDS MANY BARRIER ISLANDS INCLUDING THE LONGEST S. PADRE OCEANS OF THE WORLD INDIAN SMALLEST OF THE LARGER OCEANS AVG DEPTH 13,000 FT ALMOST COMPLETELY IN THE S. HEMISPHERE 3 OF THE WORLDS LARGEST RIVERS DUMP INTO THE NORTH INDIAN CONTRIBUTES TO HIGH LEVELS OF SEDIMENT AND FRESHWATER IN THE OCEAN OCEANS OF THE WORLD

SOUTHERN OCEANS OF THE WORLD NEWEST OCEAN AVG DEPTH 13,100 FT ONLY OCEAN THAT COVERS A FULL 360 OCEAN IS SEPARATE FROM BORDERING OCEANS DUE TO ANTARTIC CIRCUMPOLAR CURRENT YOUNGEST OCEAN GEOLOGICALLY SPEAKING ARCTIC SMALLEST OCEAN AVG DEPTH 3,500 FT UNIQUE BECAUSE IT IS ALMOST COMPLETELY SURROUNDED BY LAND COVERED IN ICE MOST OF THE YEAR ONLY 2% OF THE WORLD S OCEAN WATER OCEANS OF THE WORLD