the earth's history, structure and composition
TRANSCRIPT
The Earth’s History, Structure &
Composition Earshad B. BanjalInstructor – Physical Sciences Math & Science DepartmentCollege of Arts & Sciences EducationUniversity of MindanaoBolton, Davao City
The Moving Earth
The Moving Earth
Continental Drift TheoryContinental Drift Theory by Alfred WegenerAll continents were once connected and united as one supercontinent called Pangaea.
Pangaea broke off into Laurasia and Gondwanaland
The Moving Earth•The ground below you travels at a rate of 10 cm. per year•This is because of Plate Tectonics, or the large scale movement of Earth’s continents.
Layers of the EarthThree main structures (inner)1. Crust2. Mantle3. Corei. Outerii. Inner
Layers of the Earth1. Crust - outermost layer of the
Earth composed mainly of alumino-silicates
Layers of the EarthTwo main structures1. Crusta. Continental
crust Thicker layer; forms the continents and shallow water close to the shores; made of granite rocks
Two main structures1. Crust
b. Oceanic crustThinner layer; forms the ocean basins; made of basaltic rocks
Layers of the EarthTwo main structures2. Mantle - Denser than the
crust; consist mostly of iron;
i. upper part is bounded by Mohorovicic discontinuity (Andrija Mohorovicic)
ii. Lower part is bounded by Gutenberg discontinuity (Beno Gutenberg)
Layers of the EarthTwo main structures2. Mantle - Denser than the
crust; consist mostly of iron;
i. upper part is bounded by Mohorovicic discontinuity (Andrija Mohorovicic)
ii. Lower part is bounded by Gutenberg discontinuity (Beno Gutenberg)
The Mantle
Layers of the EarthTwo main structures3. Core
i. Outer core – fluid molten Fe and Ni
ii. Inner coure – solid made of Fe
Collective Layers of the EarthMain inner layers:1. Lithosphere2. Asthenosphe
re
Structure of the Earth1. Lithosphere which includes the
crust and the uppermost mantle, comprises the land around you.
2. Asthenosphere – the highly viscous but solid rock portion of the upper mantle, wrapping around the core; 80 – 120 km below the surface
The Asthenosphere
Separated by Tectonic Plates
The Tectonic PlateThe South American Plate is an example of a Tectonic Plate made of two crusts: Continental Crust (the continent South America) and the Oceanic Crust (large region of Atlantic Ocean).
Tectonic Plates Collectively comprising the lithosphere, Tectonic Plates are more brittle and stiff than the heated malleable layer of Asthenosphere.Thus, the Tectonic Plates float on top of the Asthenosphere and move independently of one another.
Tectonic Plates
Three Basic Types of Plate BoundariesDivergent
ConvergentTransform
Subduction, Faulting & FoldingSubduction – one plate goes below the otherFolding – when rocks undergo tremendous pressure producing folds which give rise into land formationsFaulting – the formation of cracks in crust layers
Faults & EarthquakesFaults – cracks in rock layersFocus – the point where the fault movedi. intermediate focus
– happens in upper mantle (70-350 km)
Epicenter – place on top of the focus
FaultingNormal Faults – the hanging wall block moves downward relative to the footwall blockReverse Faults – the hanging wall block moves upward relative to the footwall block
a. Thrust – horizontal movement of the ground
b. Uplift – rising of crust
Faults & EarthquakesEarthquake – any movement or shaking of the ground1. Tectonic2. Volcanici. Tsunami
Richter scale-measures magnitude/quantity of freed energy- by Charles Richter
Mercalli Intensity Scale-assigns a degree to the effects on the environment (Intensity)- By Giuseppe Mercalli
Earthquakes can be detected by a Seismograph
2011 Sendai Japan, Mag. 9.0
Worst Earthquakes and Tsunami in the History
Source: US Geological Survey1. The Great Chilean Earthquake (1960) – 6,000 people
died; magnitude 9.5/ intensity IX2. Sendai, Japan Earthquake (2011) - most powerful
earthquake ever recorded in Japan with 15,890 deaths, 6,152 injured and 2,590 missing; magnitude 9.0
3. Sichuan, China Earthquake (2008) – millions of people were left homeless after their house fell down; lasted for 2 minutes; magnitude 8.0
4. Haiti Earthquake (2010) – magnitude 7.0; 200,000 deaths
5. Sumatra, Indonesia (Dec. 26, 2004) – magnitude 9.3; deadliest tsunami ever 215,000 people died from Indonesia, Sri Lanka, Thailand, India and Somalia
The Pacific Ring of Fire
Intensity Scale used by the Philippine Volcanology & Seismology (PHILVOLCS)
INTENSITY DESCRIPTIONI Scarcely perceptibleII Slightly felt – still waters oscillates
slowlyIII Weak – dizziness; hanging objects
swingIV Strong – sleeping people are
awakenedV Very Strong – very old or poorly built
house toppleVI Destructive – landslides are observed
Intensity Scale used by the Philippine Volcanology & Seismology (PHILVOLCS)INTENSITY DESCRIPTION
VIII Very Destructive – people panicky. Difficult to stand.
IX Devastating – people are forcibly thrown to ground.
X Completely Devastating – All man made structures are
destroyed
DiastrophismFolds – warps in layered bedrocksDiastrophism refers to the series of processes (folding and faulting) by which the major features of the Earth’s crust are formed and changed because of relative changes of positions and deformation of rock.
Minerals Minerals – naturally occurring, solid, has definite chemical composition, and generally inorganic; may be identified by its:1. Crystal form2. Hardness3. Cleavage and Fracture4. Color or Streak5. Specific Gravity
Mineral DepositsOre is a kind of mineral deposit with a high concentration of at least one metallic element.Example: GOLD ORE & COPPER ORE
Mineral DepositsMetallic minerals: Cadmium, chromium, cobalt, copper, gold, silver, lead, iron, manganese, mercury, nickel, palladium, uranium and zinc.
Mineral DepositsNon-metallic minerals: asbestos, cement raw material, dolomite, feldspar, gypsum, marble, phosphate, sulfur and talc.
Minerals Mineral ores
ChalcopyriteChromiteGalenaMagnetitePitchblende
Minerals obtained
CopperChromium
LeadIron
Uranium
Mineral Deposits•Philippine mineral deposits are thought to be at 30.8 billion MT, of which 37% are metals and 63% are non-metals•Our prime contributions to foreign exchange earnings valued at 3 billion USD in 2000
How are oil and gas made ?
Why use Oil & Natural Gas?
Since 1910, oil and natural gas have replaced coal because they are “environmentally clean”.They can also be refined.Almost all countries in the world burn fossil fuels for energy.
In the Philippine settingFirst Oil Well in the Cebu, Philippines was drilled in 1986.We rely from OPEC and its 13 member countries.Organization of Petroleum Exporting Countries (OPEC) processes 56-84% of the world’s oil production and export.
OPEC, the War in the Mideast, & Oil Crisis
•Saudi Arabia has the largest oil reserves producing at a cost of 12 cents a barrel to 3 USD.•1973 18-day War with Israel, OPEC instituted Oil Embargo (12 USD/ barrel)•1979, Iranian revolution (35 USD/ barrel) •1990, Iraq’s invasion of Kuwait (40 USD/ barrel)
Geothermal ResourcesNon renewable but perpetual energy resources.1. Hot springs2. Wells3. Near vents4. Caldera
Geothermal ResourcesIn the Philippines, we have geothermal power plants in:1. Leyte2. Tiwi, Albay3. Makban, Quezon4. Laguna5. Negros Occidental6. Mt. Apo
Rocks Rocks - aggregate of minerals; formed by weathering, erosionTypes:1. Igneous - cooled and crystallized magma or lava2. Sedimentary - from pre-existing rock, or from
dissolved compounds worn away from other rocks, that are transported by wind, water, or ice
3. Metamorphic - from pre-existing rocks, that, without melting, are transformed by high temperature, high pressure, or both
Igneous Rocks•Formed by the cooling of Magma
magma
volcano
Igneous Rocks 1. Intrusive or
Plutonic rocks – when cooled and solidified underground
2. Extrusive - when cooled and solidified on land or seafloor
Granite
Gabbro
Basalt
Rhyolite
Sedimentary Rocks• Sedimentary Rocks are rocks
formed when particles of sediment build up and are “cemented together” by the effect of pressure and minerals.
sea
Fragments washed to the sea
Sedimentary rocks
Rocks are brokenup by the actionof weather
Getting older
Sedimentary Rocks Coal is chemical sedimentary rock formed through stages of:a. Peatb. Lignitec. Bituminousd. Anthracite
How is coal formed ?
Sedimentary Rocks Generally made of Calcium carbonate1. Limestone2. Sandstone3. Shale4. Chalk5. Dolomite
Limestone
Sedimentary Rocks
Clastic (Calcite + Quartz)
Coal
Metamorphic Rock• The literal meaning
is to “change shape”
Rocks change with temperature and pressure, but remains solid
Usually takes place deep in the Earth
Metamorphic Rocks• Metamorphic rocks are formed by the effect of heat
and pressure on existing rocks.• This can greatly affect the hardness, texture or
layer patterns of the rocks.
Magma
metamorphicrock forming here
heat
Pressure from surface rocks
Metamorphic Rocks Metamorphic rocks are formed by the effect of heat and pressure on existing rocks.
Marble
Quartzite
Gneiss
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