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Transcript
SES4U Final Exam Notes 1. Sun, Moon, Earth Terms Spinoff: technology developed in space program that now has common commercial uses Eclip9c: plane of Earth’s orbit around the sun Ejecta: material blasted out of the Moon’s surface as a result of space-‐object impacts Reflec9ng Telescope: a device that brings visible light to a focus with mirrors Summer sols9ce: Earth’s posi<on around June 21, at which the northern hemisphere has its maximum daylight hours Winter sols9ce: Earth’s posi<on near or on December 21, at which the northern hemisphere has its minimum daylight hours Autumnal Equinox; Earth’s posi<on when the lengths of day and night are equal Synchronous rota9on: Moon’s state, in which its rota<onal period and its orbital period are equal Mare: a dark, smooth plain on the surface of the moon Regolith: a loose, ground-‐up rock on the Moon’s surface Interferometry: a process of linking separate radio telescopes to act as one Solar Eclipse: the blocking of the disk of the sun by the Moon Albedo: the por<on of sunlight reflected by the Moon’s surface Perigee: closest point to Earth in the Moon’s orbit Apogee: farthest point from Earth in the Moon’s orbit 2. Main Ideas: -‐Electromagne9c spectrum is the arrangement of waves that includes gamma rays, X rays, ultraviolet radia<on, visible light, infrared radia<on, microwaves and radio waves according to the wavelength and frequency, -‐The telescope that uses lenses to bring visible light to a focus is a refrac9ng telescope -‐Telescopes are placed above the atmosphere in order to most effec<vely collect infrared and ultraviolet radia<on, X-‐rays, and gamma rays SES4U Final Exam Notes -‐The space explora<on program that landed astronauts on the Moon was Apollo -‐The Moon’s surface is very different from the surface of Earth because the Moon has no erosion -‐The theory that suggests the Moon was formed at about the same <me as Earth and from similar materials is called the simultaneous forma9on theory -‐The daily rising and seNng of heavenly objects like Sun is caused by the rota9on of Earth -‐One reason different seasons occur on Earth is because Earth’s axis is <lted 23.5o rela<ve to the eclip<c -‐When the Moon waxes during its lunar cycle, the amount of its sunlight por<on that we see appears to increase in size -‐A lunar eclipse occurs when Earth passes between the Sun and Moon -‐A lunar eclipse can only occur during the phase of the full moon 3. Earth Moon Mystery Ar9cle Q&A 1) Is the moon geologically ac<ve? -‐Moon is geologically not ac<ve -‐Moon is like a control-‐ it is not as complicated as the earth is-‐ no weathering, no plate tectonics 2) What was the Lunar Magma Ocean? Describe some of its characteris<cs -‐sea of molten rock; very hot about 1 200 degrees, several hundred miles deep 3) What are the bright whi<sh areas called on the moon’s surface? What are the darker areas called? -‐Bright whi<sh-‐gray areas are mountains called Lunar Highlands which is made of anorthosite (light minerals) -‐Fla_er grayish-‐black areas are called Lunar Mare which is made of basalt (lava outpourings) 4) Outline four main models of lunar forma9on 1 The intact capture model: earth and moon are formed separately in solar system; rela<vely non-‐violent 2 The coaccre9on model: both bodies form from the same material at the same <me 3 Earth Fission model: earth divides out due to molten and rapid rota<on 4 Collision Ejec9on model: mars sized object collides with earth and moon forms out of rings of debris ejected SES4U Final Exam Notes 5) Is there a difference between the oxygen isotope data on the moon and the earth? Which model does this data support? -‐Comparison of 0 isotopes in crust-‐ similar in both the moon and earth -‐> supports the earth fission model and the coaccre<on model 6) Which model is currently favored? -‐Collision Ejec<on Model -‐> because it answers some ques<ons about the Earth’s change in nota<on and its apparent change in axis 4. Drake Equa9on -‐terms involved in es<ma<ng the number of technological civiliza<ons that may exist in our galaxy -‐iden<fies specific factors thought to play a role in the development of such civiliza<ons N=R*fpneflfifcL -‐N= the number of communica<ve civiliza<ons -‐R*= the rate of forma<on of suitable stars (such as sun) -‐fp= the frac<on of those stars with planets (current evidence indicates that planetary systems may be common for stars like the sun) -‐ne= the numbers of Earth-‐like worlds per planetary system -‐fl= the frac<on of those Earth-‐like planets where life actually develops -‐fi= the frac<on of life sites where intelligence develops -‐fc= the frac<on of communica<ve planets (those on which electromagne<c communica<on technology develops) -‐L= the “life<me” of communica<ng civiliza<on *Problem with this equa<on is that everything passed fp is really unknown. 5. Seasons -‐Moon did influence season early in our history-‐ the collision that may have formed the moon <lted the earth’s axis at 23.5 degrees from normal -‐Moon stabilized earth’s wobble -‐Moon does not influence seasons now -‐Seasons are not driven by how close or far we are from the sun; we are actually closer in the winter; further in the summer -‐Seasons are driven by the <lt of the earth and what part of what hemisphere is facing the sun at which <me of the year SES4U Final Exam Notes 6. Gravity -‐The strength of the force of gravita<on (FG) between two objects depends on the mass of the objects and the distance separa<ng them -‐FG is directly propor<onal to the product of masses -‐FG a m1 m2 -‐> FG is measured in newtons -‐> m1 & m2 measured in kilograms -‐Let m1= mass of earth & m2= your mass -‐> if mass of earth is doubled, FG between you and the Earth is doubled -‐> if m2 is doubled, FG between you and the Earth is doubled -‐> if both mass of earth and m2 is doubled, FG between you and the Earth is quadrupled -‐FG is inversely propor<onal to the square of the distance between the centres of the objects -‐> FG a 1/d2 -‐The combined expression: FG = Gm1m2, where G= 6.67 x 10-‐11 N*m2 d2 kg2 -‐Therefore, gravity is a weak force -‐For FG to be great, the interac<ng masses must be large and/or separa<on must be small -‐Why does gravita<onal field strength at Earth’s surface vary between 9.78m/s2 and 9.83m/s2? è “g” is greater than average at the poles because Earth’s radius at the poles is at its smallest è “g” is lesser than average at the equator because Earth’s radius at the equator is at its largest 7. Tides è Tides are the result of the gravita<onal effects of the Sun and Moon on Earth’s oceans Spring Tide: Moon Sun -‐The difference between high and low <de is at its greatest -‐Occurs just aper a new or full moon SES4U Final Exam Notes Neap Tide: Sun Moon -‐The difference between high and low <de is at its lowest -‐Occurs at the first and third quarters of the moon l Why do astronauts appear to be weightless when they are in orbit? è Microgravity= apparent weightlessness è g= 9.8m/s2 at Earth’s surface, for everything! 8. Origins: The Earth is Born -‐ Early Earth is described as hellish, hot, bombarded and lifeless -‐Sun forma<on may have triggered by supernova; elements such as H, He, Fe, C, all elements beyond Fe were found -‐Early Earth have grown due to collision between rocks, gravita<onal a_rac<on and accre<on -‐Asteroids and meteorites will help us get the snapshot of the early Earth -‐Carbon, water and radioac<ve isotopes are found on that meteorite and gives us the age of solar system -‐Age is about 4-‐4.5 billion years -‐Condi<ons such as molten planet, bombarded from space, radioac<ve decay gave rise to Iron Catastrophe -‐*Iron Catastrophe: heavy metals like iron and nickel migrate to the core -‐>this lead to differen<ated planet -‐*Spinning core: it protects earth by: the molten core spinning and swirling which creates electric current and magne<c field then deflects the solar wind and eventually protects the planet -‐Nebula: debris exists with a vast cloud of gas and dust called a nebula 9. Discoveries of Galileo -‐Moon surface= rough and uneven -‐> the surface is covered with craters, mountains and valleys -‐sunspots, landscape on moon, Jupiter moons, jail, ideas of universe -‐supports Copernican idea that Earth and other planets orbit the Sun SES4U Final Exam Notes 10. Addi9onal informa9on from ar9cles 1 Describe what happened to Mars: è Mars too small; core cooled and solidified; no more magne<c field; no barrier to solar wind; solar wind strips atmosphere 2 How was the Moon formed? è Formed as same <me as Earth 3 What did astronauts find out about age of Moon? è Younger than the earth; some composi<ons as the outer part of the earth 4 What did the new Moon do for the early Earth? è Stabilized the earth rota<on; reduced the earth’s wobble; 23.5 degrees from normal gives the earth seasons 5 Where did life begin? è Under the surface (refuge from bombardment) è Under the oceans (hydro thermal vents) è Opposi9on: the term used to describe two celes<al bodies as being opposite each other in the sky, rela<ve to the observer. An exam is when the Moon is opposite the Sun, with the observer on the Earth in the middle 11. Geologic Time -‐Geologic Time Scale: record of Earth’s history from its origin 4.6 billion years ago to the present -‐> By studying rock layer and fossils within them, geologists can reconstruct aspects of Earth’s history and interpret ancient environment -‐>Enables to organizes <me into meaningful “chunks”, context to understand <me frames -‐Eon: the largest of <me units (Hadean, Archaen, Proterozoic, Phanerozoic) -‐Precambrian: unit of geologic <me consis<ng of the first three eons during which Earth formed and became hospitable to life; makes up nearly 90% of geologic <me -‐Era: ten-‐hundreds of millions of years in dura<on (Paleozoic, Mesozoic, Cenozoic) -‐Periods: tens of millions of years in dura<on -‐Epochs: hundreds of thousands to millions of years in dura<on -‐Bascially: Eon > Era > Period > Epoch Phanerozoic > Cenezoic > Neogene > Holocene Phanerozoic > Mesozoic > Cretaceous Phanerozoic > Paleozoic > Silurian Phanerozoic > Paleozoic > Cambrian -‐Why do scien<sts know more about the Cenozoic than they do about other eras? SES4U Final Exam Notes è We live in it; shorter <me phrase; no <me for material(rocks) and fossils to disappear -‐Why do scien<sts know so li_le about Precambrian Era? è Long <me frame; we aren’t there; lots of <me for erosion -‐Ex<nc<on events determine the divisions of eras and periods on the geologic <me scale -‐Cenozoic era is divided into both periods and epochs -‐Geologists study fossils for paleo ecology where they can find out the pa_erns of life, predict and/or protect future -‐We live in Holocene epoch, Quaternary period and Cenozoic era -‐Major divisions of Earth’s history are Eras -‐Each major division may be divided into periods -‐The Cenozoic Era is divided into epochs -‐Clues to which organisms lived in different eras are found in fossils -‐A gradual change in life-‐forms over <me is organic evolu<on -‐Aper major changes in Earth’s environments, species either died out or adapted -‐Organisms with traits that are suited to an environment survive by the process of natural selec<on -‐Plate tectonics caused collision and separa<on of con<nents -‐Many species adapted or became ex<nct because plate tectonics caused their environments to change when the con<nents collided or separated -‐Protorozoic era lasted the longest -‐Hadean era is the oldest Order of which species appeared on Earth: - iron catastrophe-‐> origin of the moon -‐> great bombardment -‐> Origin of Life-‐> Cyanobacteria -‐> oxygen & ozone layer -‐> shielding of Earth from ultraviolet rays -‐> complex organisms (mul<cellular)-‐> invertebrates -‐> organisms with hard parts (shells) -‐> fish –amphibians -‐> rep<les -‐> Pangaea (all Earth) -‐Why did coal deposits begin to form in the Paleozoic Era? -‐> Forma<on of vast forest + swamps Mass Ex<nc<on: many groups of organisms disappear from the rock record at about the same <me è the end of Palezoic Era is marked by the largest mass ex<nc<on event in Earth; forma<on of Pangea and Catastrophe caused Mass Ex<nc<on in that era What happened to all of the con<nental plates near the end of the Paleozoic Era? –they merged into one 12. Key Concepts in development of Geologic Time -‐Up to late 1700s, Earth history was based on biblical interpreta<on only -‐Catastrophism: a belief that the varied landscapes were created by great catastrophes in history; e.g. Noah and the Flood -‐Uniformitarianism: the physical, chemical and biological laws that operate today have also SES4U Final Exam Notes operated in the geological past-‐ “the key to the present is the key to the past” -‐<me/geology/history of planet/challenge to religion point of view 13. Fossils -‐The preserved remains or traces of once-‐living organisms -‐> provided evidence that species have changed over <me on this planet è fossils help determine sequence of rock layers and the rela<ve ages of rocks è shows the succession of life forms 14. Index Fossils: è The fossil remains of an organism that lived in a par<cular geologic age, used to iden<fy or date the rock or rock layer in which it is found è The best type of index fossils are usually those of swimming or floa<ng organisms that evolved quickly and were able to spread over large areas (such as ammonites & graptolites) è More useful than other fossils; easily recognized, abundant, widely distributed, short <me frame 15. Rela9ve Da9ng vs. Absolute Da9ng -‐Absolute Da9ng: used to give an actual age (ex. Radioac<ve decay) -‐Rela9ve-‐age Da9ng: used to establish the order of past geologic events (through different principles) Principles of Rela9ve Da9ng -‐Original horizontality: the principle that sedimentary rocks are deposited in horizontal or nearly horizontal layers -‐Cross-‐cudng rela9onships: an intrusion is younger than the rock it cuts across -‐Superposi9on: the principle that in an undisturbed rock sequence, the oldest rocks are at the bo_om and each consecu<ve layer is younger than the layer beneath it Absolute Da9ng – Radioac9ve Decay -‐The atoms of some chemical elements have different forms called isotopes. These break down over <me in a process called radioac<ve decay. Each original isotope called the parent gradually decays to form a new isotope called the daughter. When the number of parent atoms decreases, the number of daughter atoms increases by the same amount. Isotopes are important because each radioac<ve element decays at a constant rate. These rates of decay are known so that one can measure the propor<on of parent and daughter isotopes in rocks now; one can calculate when the rocks were formed Principle of inclusions: the fragments called inclusions in a rock layer must be older than the rock layer that contains them -‐Unconformi9es: gap in the rock record caused by erosion or weathering -‐Disconformity: when a horizontal layer of sedimentary rock overlies another horizontal layer of sedimentary rock (harder to see b/c they are flat) -‐Nonconformity: a layer of sedimentary rock overlies a layer of igneous or metamorphic rock such as granite or marble, the eroded surface SES4U Final Exam Notes is easier to iden<fy -‐Angular unconformity: a horizontal layer of sedimentary rock is later laid down on top of the <lted eroded layers 16. Structure of Earth: chemical vs. physical proper9es Chemical proper9es: Crust (silicates) – Mantle (Silicates) – Core (Iron) Physical proper9es: I. Lithosphere: Rigid outer; subdivided into con<nental and oceanic lithosphere II. Asthenosphere(plas9c): underlies the lithosephere; sop, par<ally molten layer III. Mesosphere(solid): main bulk of planet-‐ highly viscous (firm-‐plas<c) IV. Outer core: liquid material V. Inner core: solid, high-‐density, nickel-‐iron sphere; it spins and is the source of the earth’s magne<c field 17. Plate tectonics & Sea Floor Spreading -‐The theory of plate tectonics describes how the plates move, interact, and change the physical landscape -‐The surface of earth is broken into large plates; the size and posi<on of these plates change over <me; the edges of these plates are sites of intense geologic ac<vity such as earthquakes, volcanoes, and mountain building -‐Sea Floor Spreading -‐> the hypothesis that new ocean crust is formed at mid-‐ocean ridges and destroyed at deep-‐sea trenches; occurs in a con<nuous cycle of magma intrusion and spreading Key Evidences to Sea Floor Spreading: 1 Sonar è Allowed for mapping of ocean floor è Ocean has ridges and under water mountains; Mid-‐Atlan<c Ridge and deep trenches 2 Magnetometer è Picked up background hiss-‐ turned out to be magne<c signature in the ocean rocks è When rocks are newly formed, any magne<c components in the rock will line up in the direc<on of magne<c north pole 3 Pa_erns in Ocean rock magne<sm è Rocks flipped between north&south poles in a defined pa_ern è Reversal pa_ern leading away from the ridge all the way to the con<nental shelves *Old rock is pushed aside by a new rock 4 Age of Ocean Rocks also varied è Ridge rocks-‐ youngest, ocean floor-‐ furthest away from the ridge being the oldest 5 Deposi<on of Sediment è Ocean floor= spreading apart from the middle (meaning older) and is being destroyed in the trenches 18. Boundaries: SES4U Final Exam Notes è Convergent Boundaries: two plates move towards each other resul<ng in one plate sliding underneath the other è Divergent Boundaries: as two plates on either side of magma chamber are pulled apart, they create a void that is filled with new magma that solidifies and creates new oceanic crust è Transform Boundaries: two plates are sliding horizontally past one another 19. Driving Mechanisms 1) Convec<on: crust cools and heats repe<<vely and plate pulls apart due to tension 2) Ridge Push 3) Slab Pull 20. Henry Hess è Figured out how plate tectonics worked è Worked on origin of ocean basins & island arcs, mountain building and the movement of con<nents è Suggested that con<nents do not move across oceanic crust but rather that the con<nents and oceanic crust move together; states that the seafloor separates at oceanic ridge where new crust is formed by upwelling magma; as the magma cools, the newly formed oceanic crust moves laterally away from the ridge 21. Subduc9on zone è An area where two plates move towards one another and one moves under the other; creates a trench SES4U Final Exam Notes è Creates earthquakes since subduc<on zone is a place where crustal plates are being forced down into the mantle below other crustal plates; the fric<on causes the plates to lock in posi<on un<l the stress exceeds the shear strength of the fault zone 22. Problem in Australia -‐> their geological loca<on do not provide enough nutrient -‐> they do not have earthquakes, volcanoes or any other kind of erup<ons where they might help carry minerals and soils to the ground as it explodes -‐> lacks of glaciers 23. Con9nental Margins 1 Passive Margin: è Not a plate boundary; both con<nent and oceans are locked together as part of same plate; no trenches; volcanoes; or earthquakes è Ex) North America & Southern and Western margins of Australia 2 Ac9ve Margin: è At or near plate boundaries è Ex) Iceland-‐ Western North America; Nasca-‐ South American Plate 24. Con9nental Breakups-‐ “Breaking Up is hard to do” è Mid-‐con<nental break is preceded by con<nental uplip (dome); the development of mid-‐con<nental rips è As con<nent drips over a hotspot, it is liped è As con<nent rises, it fractures-‐ and rip valley is born è Breaking of (con<nental crust) involves the forma<on of a y-‐shaped break called a triple-‐junc<on; each arm is called GRABEN è Failure structures are called AULACOGENS; and are typically when large rivers and lakes are found 25. Magma/Intrusions/Volcanoes è Magma: mixture of molten rock, mineral grains and dissolve gas è Some factors that affect forma<on of Magma-‐ to melt rock-‐ include increase in temperature, decrease in pressure; and addi<on of water è Types of Magma 1 Basal9c: -‐low silica content; low viscosity; least explosive; from upper mantle; linked to shield volcanoes 2 Andesi9c: -‐medium silica; medium viscosity; medium explosive -‐along con<nental margins at subduc<on zones -‐from oceanic crust and oceanic sediments -‐linked to both cinder and composite volcanoes SES4U Final Exam Notes 3 Rhyoli9c: -‐highest silica; highest viscosity; most explosive -‐from con<nental crust where interac<on with silica is greatest -‐linked to composite volcanoes è Types of volcanoes 1 Shield Volcanoes: -‐Largest of the three types of volcanoes -‐Basal<c Lava -‐Quiet erup<ons 2 Cinder Cones: -‐Smallest of the three types of volcanoes -‐Andesi<c Lava -‐Explosive erup<ons 3 Composite volcanoes: -‐Considerably larger than cinder cones -‐Rhyoli<c Lava -‐Most explosive erup<ons è Intrusions I. Plutons: intrusive igneous rock bodies II. Batholiths: irregular shaped masses of coarse grained rocks which is found in the interior of mountains III. Stocks: irregularly shaped plutons that are similar to batholiths but smaller in size IV. Laccoliths: mushroom shaped pluton with round top and flat bo_om; cause overlying rocks to curve upwards V. Sill: Pluton that intrudes parallel to rock layers VI. Dyke: Pluton that cuts across rock layers 26. Pressure and Water influence 1. Pressure: -‐higher pressure increases the temperature for mel<ng -‐Why? -‐> the pressure helps hold the atoms in place; the more pressure, the more <ghtly the atoms are held, the greater temperature required to split them apart -‐Therefore, high pressures in the mantle rocks prevent atoms within mineral from breaking chemical bonds and moving freely from one another to form a liquid (magma) -‐when pressure is reduced the result is mel<ng of the rock & when pressure increases the tock becomes hardened 2. Water: -‐small amounts of water in rock will result in a decrease in a mel<ng temperature -‐electrical polariza<on causes a decrease in bond strengths within minerals and so the rock will melt at lower temperatures -‐in essence, the water interferes with the chemical bonds in the rock making it SES4U Final Exam Notes easier to break apart and for a liquid 27. Types of Lava -‐> pahoehoe lava: -‐surface looks silky and smooth but its texture is unpleasantly gri_y and coarse because the sugar crystals, while few, have grown large -‐>’a’a lava: more rough and broken surface -‐>The major difference comes from their appearance of the surfaces and they also differ in the way they flow 28. Scales è Mercalli: -‐based on damage -‐rela<ve scale which means that it is not based on real earthquake but rather on human infrastructure è Richer: -‐Describes the earthquake’s magnitude by measuring the seismic waves that cause the earthquake 29. Stress/Fault/Boundary Stress Compression Tension Shear Fault Reverse Normal Strike Slip Boundary Convergent Divergent Transform 30. Waves I. Body Wave -‐a seismic wave that moves through the interior of the earth -‐P wave: Primary -‐> compressional-‐> travels in a straight line -‐>squeezes and pulls rocks in the same direc<on as wave travels -‐S wave: Secondary SES4U Final Exam Notes -‐>goes up and down; more damage II. Surface Wave -‐a seismic wave that travels near the surface of the earth -‐Love wave: -‐> a surface wave having a horizontal mo<on that is transverse (perpendicular) to the direc<on the wave is travelling -‐Rayleigh Wave: -‐>a seismic surface wave causing the ground to shake in an ellip<cal mo<on, with no transverse (가로지르다) or perpendicular mo<on 31. Hypocenter & Epicenter Hypocenter: the loca<on of earthquake under the surface Epicenter: the point of earth’s surface directly above the focus of an earthquake 32. Minerals -‐Minerals are naturally occurring, solid, inorganic material, open in crystal form; there are 4000 known minerals; ex. Halite, gold, diamond -‐More than 90% of minerals are made up of oxygen and silicon -‐Most minerals are compounds of various elements-‐ top 8 make up 98.5% of the crust’s mass -‐re-‐crystalliza<on or forma<on of new minerals is response to pressure -‐as pressure and temperature increase; con<nued re-‐crystalliza<on and forma<on of new mineral assemblages How do we iden9fy minerals? è Rely on several simple tests: based on a mineral’s physical and chemical proper<es which are crystal form, luster, hardness, cleavage, fracture, streak, color, density, specific gravity and special proper<es Crystal form: some minerals form in such dis<nct crystal shapes Luster: the way minerals reflect light from its surface Hardness: a measure of how easily a mineral can be scratched Cleavage: when mineral splits rela<vely easily Fracture: minerals that break with rough or jagged edges Streak: colour of a mineral when it is broken up and powered Colour: Caused by the presence of trace elements or compounds within a mineral Types of Minerals 1) Silicates: -‐contains silicon and oxygen, and usually one or more other elements -‐basic building block of the silicate is silica tetrahedron, a geometric solid having four sides that are equilateral triangles, resembling pyramid 2) Carbonates: -‐composed of one or more metallic elements and the carbonate ion 3) Oxides: -‐compounds of oxygen and a metal SES4U Final Exam Notes 4) Other groups -‐include sulfides, sulfates, halides, and na<ve elements 5) Ores: -‐a mineral is an ore if it contains a valuable substance that can be minded at a profit 6) Gems: -‐Valuable minerals that are prized for their rarity and beauty (rubies, emeralds, diamonds) *Minerals are used as resources such as construc<on, energy produc<on and jewelry making** 33. Rocks Types of Rocks: Igneous Rock Sedimentary Rock -‐Form from cooling magma or lava -‐>Intrusive rock (plutonic): cooled underground and solidified slowly; individual crystals can be easily seen by the naked eye -‐> ex. granite -‐>Extrusive rock (volcanic): cooled quickly and solidified only aper erup<ng onto the surface; individual crystals cannot be easily seen by the naked eye -‐>ex.basalt Characteris9cs -‐interlocking texture of grains; may display two different grain sizes; usually dark-‐coloured and dense; some have holes; composed of crystals -‐Form from the bonding of rock fragments such as sand, silt, or clay; from organic materials; and from chemicals dissolved in water -‐Clas9c: formed from weathered and eroded rocks; these chunks of rocks are essen<ally cemented into a new rock -‐Chemical: formed when minerals dissolved in water precipitate out -‐Organic: formed from remains of living things such as clamshells, plankton skeletons, dinosaur bones, and plants -‐ex. Limestone, shale Characteris9cs Grains cemented together; may sow presence of fossils; usually light-‐coloured and low density; show layers or bands Metamorphic Rock SES4U Final Exam Notes -‐Form when other rocks are changed by heat, pressure and chemical deep inside the earth -‐Foliated: mineral grains re-‐align themselves into bands -‐Non-‐foliated: mineral grains do not re-‐align themselves into bands Characteris9cs Interlocking texture of large grains; generally show folia<on (layer); open show banded light and dark colours; open make “ching” sound instead of “chung”
