geology and the rock cycle. geologic processes the earth is made up of a core, mantle, and crust...
TRANSCRIPT
GEOLOGIC PROCESSESGEOLOGIC PROCESSES The earth is made up of a core, mantle, and The earth is made up of a core, mantle, and
crust and is constantly changing as a result crust and is constantly changing as a result of processes taking place on and below its of processes taking place on and below its surface.surface.
The earth’s interior consists of:The earth’s interior consists of: CoreCore: innermost zone with solid inner core and : innermost zone with solid inner core and
molten outer core that is extremely hot.molten outer core that is extremely hot. MantleMantle: solid rock, under which is the : solid rock, under which is the
asthenosphere that is melted pliable rock.asthenosphere that is melted pliable rock. CrustCrust: Outermost zone which underlies the : Outermost zone which underlies the
continents. (Lithosphere)continents. (Lithosphere)
Fig. 15-3, p. 337
Spreading center Ocean
trench
Plate movement
Subduction zone
Oceanic crust
Continental crust
Continental crust
Material cools as it reaches
the outer mantle
Cold dense material falls back through
mantleHot
material rising
through the
mantle
Mantle convection
cell
Two plates move towards each other. One is subducted back into the mantle on a falling convection current.
Mantle
Hot outer core Inner
core
Plate movement
Collision between two continents
Tect
onic
pl
ate
Oceanic tectonic
plate
Oceanic tectonic plate
Oceanic crust
INTERNAL GEOLOGIC INTERNAL GEOLOGIC PROCESSESPROCESSES
Huge volumes of heated and molten rock Huge volumes of heated and molten rock moving around the earth’s interior form moving around the earth’s interior form massive solid plates that move extremely massive solid plates that move extremely slowly across the earth’s surface due to slowly across the earth’s surface due to convection currents.convection currents. Tectonic platesTectonic plates: huge rigid plates that are : huge rigid plates that are
moved with convection cells or currents by moved with convection cells or currents by floating on floating on magmamagma or molten rock. or molten rock.
Fig. 15-2, p. 336
Volcanoes
Folded mountain belt
Abyssal floor
Oceanic ridge
Abyssal floor TrenchAbyssal hills
Craton
Abyssal plain
Oceanic crust (lithosphere)
Continental Continental shelfshelf
Aby
ssal
pla
in
Continental slope
Continental rise
Continental crust (lithosphere) Mantle (lithosphere)
Mantle (lithosphere)
Mantle (asthenosphere)
EarthEarth
orbit: 149,600,000 km (1.00 : 149,600,000 km (1.00 AU) from Sun ) from Sun diameter: 12,756.3 km : 12,756.3 km mass: 5.972e24 kg: 5.972e24 kg Earth’s layers (depths in km)Earth’s layers (depths in km)
0- 40 Crust 0- 40 Crust 40- 2890 Mantle 40- 2890 Mantle 2890-5150 Outer core 2890-5150 Outer core 5150-6378 Inner core 5150-6378 Inner core
EarthEarth
Earth’s mass (measured in 10^24 kg)Earth’s mass (measured in 10^24 kg) atmosphere = 0.0000051 atmosphere = 0.0000051 oceans = 0.0014 oceans = 0.0014 crust = 0.026 crust = 0.026 mantle = 4.043 mantle = 4.043 outer core = 1.835 outer core = 1.835 inner core = 0.09675 inner core = 0.09675
Earth’s InteriorEarth’s Interior
Core is made up mostly of iron/nickelCore is made up mostly of iron/nickel Temperatures in core reach 7500 KTemperatures in core reach 7500 K The crust is primarily quartz. The crust is primarily quartz. Taken as a whole, the Earth's chemical Taken as a whole, the Earth's chemical
composition (by mass) is: composition (by mass) is: 34.6% Iron 34.6% Iron 2.4% Nickel 2.4% Nickel 29.5% Oxygen29.5% Oxygen 1.9% Sulfur 1.9% Sulfur 15.2% Silicon 15.2% Silicon 0.05% Titanium0.05% Titanium 12.7% Magnesium 12.7% Magnesium
Major PlatesMajor Plates
North American Plate North American Plate South American PlateSouth American Plate Antarctic PlateAntarctic Plate Eurasian PlateEurasian Plate African PlateAfrican Plate Indian-Australian PlateIndian-Australian Plate Nazca PlateNazca Plate Pacific PlatePacific Plate
Plate MovementPlate Movement
The extremely slow movements of these The extremely slow movements of these plates cause them to grind into one another plates cause them to grind into one another at convergent plate boundaries, move apart at convergent plate boundaries, move apart at divergent plate boundaries and slide past at divergent plate boundaries and slide past at transform plate boundaries.at transform plate boundaries.
Figure 15-4Figure 15-4
Fig. 15-4a, p. 338
EURASIAN PLATEEURASIAN PLATENORTH NORTH AMERICAN AMERICAN PLATEPLATE
ANATOLIAN ANATOLIAN PLATEPLATE
JUAN DE JUAN DE FUCA PLATEFUCA PLATE
CHINA CHINA SUBPLATESUBPLATE
CARIBBEAN CARIBBEAN PLATEPLATE
PHILIPPINE PHILIPPINE PLATEPLATE
ARABIAN ARABIAN PLATEPLATEAFRICAN AFRICAN
PLATEPLATEPACIFIC PACIFIC PLATEPLATE SOUTH SOUTH
AMERICAN AMERICAN PLATEPLATENAZCA NAZCA
PLATEPLATEINDIA-INDIA-
AUSTRALIAN AUSTRALIAN PLATEPLATE
SOMALIAN SOMALIAN SUBPLATESUBPLATE
ANTARCTIC PLATEANTARCTIC PLATE
Divergent plate boundaries
Convergent plate boundaries
Transform faults
Fig. 15-4b, p. 338
Trench Volcanic island arc Craton
Transform fault
LithosphereSubduction zone
Lithosphere Lithosphere
Asthenosphere Asthenosphere Asthenosphere
Divergent plate boundaries Convergent plate boundaries Transform faults
Rising magma
Convergent Plate BoundaryConvergent Plate Boundary
Two plates pushed togetherTwo plates pushed together Oceanic + Continental = Subduction ZoneOceanic + Continental = Subduction Zone Oceanic + Oceanic = TrenchOceanic + Oceanic = Trench Continental + Continental = Mountain RangeContinental + Continental = Mountain Range
Divergent Plate BoundaryDivergent Plate Boundary
Plates moves apart from one anotherPlates moves apart from one another Oceanic plates form oceanic ridgesOceanic plates form oceanic ridges
Transform FaultsTransform Faults
Plates slide and grind past one another along Plates slide and grind past one another along a fracture in the lithospherea fracture in the lithosphere
Benefits of volcanoes, earthquakes, Benefits of volcanoes, earthquakes, and tsunamisand tsunamis
Geological: Geological: Recycle rock and earth’s crustRecycle rock and earth’s crust Form mineralsForm minerals
Ecological:Ecological: Speciation (due to isolation)Speciation (due to isolation) Maintaining atmosphere thus climateMaintaining atmosphere thus climate Enrich soils = more foodEnrich soils = more food
Geologic Time ScaleGeologic Time Scale
~4.6 billion years ago: Earth believed to have ~4.6 billion years ago: Earth believed to have formed, hot ball of rockformed, hot ball of rock
3.9 billion years ago: rainstorms3.9 billion years ago: rainstorms 3.5 billion years ago: oceans, first living 3.5 billion years ago: oceans, first living
organismsorganisms
Geologic ErasGeologic Eras Precambrian Era:Precambrian Era: 4.6 billion years ago- 545 million years ago 4.6 billion years ago- 545 million years ago
87% of Earth’s history87% of Earth’s history Prokaryotes dominated Prokaryotes dominated First eukaryotes appeared ~ 1.5 billion years agoFirst eukaryotes appeared ~ 1.5 billion years ago Simple multicellular organisms in seasSimple multicellular organisms in seas
Paleozoic Era:Paleozoic Era: 545 million years ago – 248 million years ago 545 million years ago – 248 million years ago ““Explosion of life”Explosion of life” Many types of invertebrates in shallow seasMany types of invertebrates in shallow seas Early: earliest vertebratesEarly: earliest vertebrates Middle: amphibiansMiddle: amphibians Later: reptilesLater: reptiles
Geologic ErasGeologic Eras
Mesozoic Era:Mesozoic Era: 248 million years ago – 65 million years ago 248 million years ago – 65 million years ago Triassic: mammals made first appearanceTriassic: mammals made first appearance Jurassic: “age of dinosaurs”Jurassic: “age of dinosaurs” Cretaceous: radiation of mammals and evolution of Cretaceous: radiation of mammals and evolution of
flowering plantsflowering plants Plate Tectonics: continental shiftPlate Tectonics: continental shift
Cenozoic Era:Cenozoic Era: 65 million years ago – now 65 million years ago – now Mammals flourishMammals flourish Primates evolvePrimates evolve Extinctions affect diversityExtinctions affect diversity Modern human species evolved ~200,000 years agoModern human species evolved ~200,000 years ago
EXTERNAL GEOLOGIC EXTERNAL GEOLOGIC PROCESSESPROCESSES
Surface processesSurface processes Based largely on energy from the sun and gravityBased largely on energy from the sun and gravity
Tends to wear down Earth’s surface and Tends to wear down Earth’s surface and produce a variety of landforms by the buildup produce a variety of landforms by the buildup of eroded sedimentof eroded sediment
ErosionErosion WeatheringWeathering
Wearing Down and Building Up the Wearing Down and Building Up the Earth’s SurfaceEarth’s Surface
Weathering Weathering is an is an external external process process that wears that wears the earth’s the earth’s surface surface down.down.
Figure 15-6Figure 15-6
EROSIONEROSION
Process by which material is dissolved, Process by which material is dissolved, loosened or worn away from one part of the loosened or worn away from one part of the earth’s surface and deposited in other placesearth’s surface and deposited in other places
Streams are most important agents of Streams are most important agents of erosionerosion
MINERALS, ROCKS, AND THE MINERALS, ROCKS, AND THE ROCK CYCLEROCK CYCLE
The earth’s crust consists of solid The earth’s crust consists of solid inorganic elements and compounds called inorganic elements and compounds called mineralsminerals that can sometimes be used as that can sometimes be used as resources.resources. Mineral resourceMineral resource: is a concentration of : is a concentration of
naturally occurring material in or on the naturally occurring material in or on the earth’s crust that can be extracted and earth’s crust that can be extracted and processed into useful materials at an processed into useful materials at an affordable cost.affordable cost.
Nonrenewable mineral resourcesNonrenewable mineral resources
Fossil fuels (oil, natural gas, coal)Fossil fuels (oil, natural gas, coal) Metallic minerals (Al, Cu, Fe)Metallic minerals (Al, Cu, Fe) Nonmetallic minerals (sand, gravel, Nonmetallic minerals (sand, gravel,
limestone)limestone)
Minerals and their UsesMinerals and their Uses
Metals Metals Al- building, cansAl- building, cans Steel- buildingSteel- building Cu- conductor, Cu- conductor,
electronicselectronics Mn, Co, Cr- used in alloysMn, Co, Cr- used in alloys Pt- catalytic convertersPt- catalytic converters
NonmetalsNonmetals Sand- glass, concrete, Sand- glass, concrete,
bricksbricks Gravel- roadbedsGravel- roadbeds Limestone- roadbeds, Limestone- roadbeds,
natural buffernatural buffer Phosphate salts- Phosphate salts-
fertilizersfertilizers
US consumptionUS consumption
8% of world population but use 75% of 8% of world population but use 75% of metals on earthmetals on earth Uses: cars, engines, appliances, weapons, Uses: cars, engines, appliances, weapons,
satellitessatellites
ROCKROCK
A very slow chemical cycle recycles three types of A very slow chemical cycle recycles three types of rock found in the earth’s crust:rock found in the earth’s crust: Sedimentary rock Sedimentary rock (sandstone, limestone). Formed from (sandstone, limestone). Formed from
sediment of pre-existing rocks that are weathered and sediment of pre-existing rocks that are weathered and erodederoded
Metamorphic rock Metamorphic rock (slate, marble, quartzite). Formed (slate, marble, quartzite). Formed when pre-existing rock is subjected to high temperatures when pre-existing rock is subjected to high temperatures or pressureor pressure
Igneous rock Igneous rock (granite, pumice, basalt). Formed from (granite, pumice, basalt). Formed from cooled magma at or below earth’s surfacecooled magma at or below earth’s surface