Earth Science Q2 PDF

Earth Science Q2 L1: Weathering Weathering - process by which rock is broken into smaller pieces 1. Physical (Mechanical) Weathering - breakdown of rock into smaller pieces, no chemical change a. Frost Action/Wedging, Freeze-Thaw Cycle - expansion of freezing water b. Thermal Expa...

Earth Science Q2 L1: Weathering Weathering - process by which rock is broken into smaller pieces 1. Physical (Mechanical) Weathering - breakdown of rock into smaller pieces, no chemical change a. Frost Action/Wedging, Freeze-Thaw Cycle - expansion of freezing water b. Thermal Expansion - repeated heating and cooling cause rocks to crack and break c. Exfoliation - peeling away of rock - due to unloading (reduced pressure) or fluctuations in temperature d. Abrasion - rocks colliding/bumping against each other + Agents: - Wind - Liquid water - Solid water - Gravity e. Biological - plants, expanding (uplift & fracture) of seeds and roots in a process called Root Action - lichen and moss, secrete acids that chemically break down rocks - animals, soil burrowing creatures (such as earthworms) 2. Chemical Weathering - chemical change in the rock - occurs at tropical regions a. Hydration - water combines with minerals Ex: Feldspar » Clay b. Carbonation - water containing carbonic (weak) acid dissolves minerals (calcite minerals) - CO2 + H2O → H2 CO3 (Carbonic Acid) Ex: Stalagmites (ground) & Stalactites (ceiling) c. Man Made Acids - Nitric & Sulfuric Acid (industrial processes, causes chemical weathering of structures) d. Oxidation - oxygen is added to other elements - rusting of magnetite into hematite - common in metallic elements and ores such as Iron (Fe) Rates: A. Climate - faster at higher temperature - requires water B. Rock Type - “Quartz” (resistant to chemical weathering) L2: Earth's Internal Heat Different Theories: 1. Big Bang Theory - universe started with a single point (singularity) - expanding and cooling - Hydrogen and Helium (responsible elements) 2. Stellar Theory - stars are basic building blocks of universe 3. Super Nova Nucleosynthesis - explosion of massive star 4. Big Crunch Theory - opposite of Big Bang - universe will stop growing, begin to shrink, got hotter Sources of Heat: 1. Primordial Heat - dissipation in a planet during its first few million years of evolution + Accretion/Accretional Energy (initial formation of the Earth) 2. Radiogenic Heat - thermal energy as a result of spontaneous nuclear disintegration - disintegration of natural radioactive elements inside the Earth such as Uranium (U) and Thorium (Th) - “Uranium (U)” — special kind of element because when it decays, radiogenic heat is produced. + Isotopes - atoms with same number of protons but different number of neutrons 3 Main Sources of Heat: 1. When the planet formed and accreted, has not been lost. 2. Frictional heating, denser core material sinks to the center of the planet. 3. From the decay of radioactive elements. Sources of Heat Transfer: A. Conduction - collisions between neighboring atoms or molecules B. Convection - through a fluid (liquid or gas) caused by molecular motion C. Radiation - heat exchange between the Sun and the Earth - warm land and water in summer, emit long-wavelength infrared radiation absorbed by the atmosphere - night time, convection in air spreads thermal energy throughout the atmosphere Thermal Radiation - absorbed by objects depends on the surface - Dark surfaces absorb most - Silver or mirrored surfaces reflect L3: Magmatism Magma - semi-liquid hot molten rock beneath the Earth, in the melted rock and oceanic plate - temperature is between 700°C - 1300°C - when reached the Earth's surface, lava - when solidifies, creates igneous rocks - originates in the lower crust and upper mantle - Oxygen is the most abundant element Magmatism - process under the Earth's crust, formation and movement of magma - occurs in the asthenosphere (upper mantle below the crust) through convection currents How do magmas formed? A. Partial Melting - different minerals melt at different temperature and pressure - addition of volatile materials such as water and carbon dioxide + Conditions: 1. Increase in temperature. Conduction - heat is transferred from hotter molten rocks to Earth's cold crust - known as Heat Transfer that happens in convergent boundaries 2. Decrease in pressure. Convection - rocks tend to go upwards, pressure is reduced, triggers the melting of magma - this process is known as Decompression Melting that occurs at Mid-Ocean Ridge (underwater mountain system) 3. Addition in volatile. Flux Melting - water or carbon dioxide is added to hot rocks - melting point decreases - occurs around subduction zone L4: Metamorphism Metamorphism - from Greek, Meta—change & Morphe—form (change in form) Metamorphic Rocks - rocks subjected to either enough heat or pressure - never melt, if they did, it would become igneous magma, changes are solid state Changes Occurs: - in the minerals - folding and bending of rocks, change in shape - recrystallization - chemical reactions to new minerals that are more stable at pressure and temperature as a result of polymorphic phase transformations Agents and Factors: 1. Heat - most important agent - geothermal gradient increases in temperature at 30°C/km Geothermal Gradient - rate at which temperature increases with depth in Earth's crust 2. Pressure - increases with depth, 1000 kg/cm² at 4km depth - minerals to melt or atoms to configurations that represent tighter packing a. Confining/Vertical Stress (Lithostatic) - equal pressure in all directions - cause to become smaller, rocks are fractured and deformed b. Directed/Differential Pressure/Stress - not equal pressure in all directions - shape and orientation of new crystals formed Protolith - parent rock - original, unmetamorphosed rock Low-grade Metamorphism  - non-foliated rocks, not/no visible crystal alignments, smooth surfaces, and breaks easily Ex: slate High-grade Metamorphism - foliated rocks, visible crystal alignments Ex: schist, gneiss 3. Time - changing the rock while it's solid, slow process (tens of millions of years) - coarse-grained involve long times 4. Fluid Phase - open space between mineral grains contain a fluid - mostly H2O, contains dissolved ions (charged particles) - speeded up by dissolved ions transported by the fluid + Metasomatism - chemical alteration of rock as a result of these fluids Types of Metamorphism 1. Regional - foliated rocks such as Gneiss and Schist - high temperature and pressure on large parts of crust - occurs within the continental crust 2. Contact - exposed to heat coming from magma intrusion within layers of rocks - with large visible crystals such as marble, quartzite, and granoblastic rocks 3. Shock - shock waves from meteor or asteroid impact 4. Burial - lower temperature and pressure - transform sedimentary rocks through diagenesis into low-grade metamorphic rock + Diagenesis - physical and chemical changes in sediments caused by water-rock, microbial, and compaction after deposition 5. High-Pressure - occurs in subduction zones between converging plates  - rarely found as they were formed in such great depth 6. Hydrothermal - by hot, metal rich fluids associated with igneous activity - most commonly at mid-ocean ridges L5: Types of Stress Stress - force that pushed and pulled the plates that acts on rocks 1. Compression Stress - causes rocks to fold or fracture - squeezes rocks together - targets the center can cause either horizontal or vertical - convergent 2. Tension Stress - rocks to be pulled apart, lengthening and break apart - caused the ancient massive continent Pangaea to break off into 7 continents - divergent 3. Shear Stress - forces slide pass each other in opposite direction - slippage and translation - friction cause earthquakes - transform 4. Confining Stress - forces are applied to all sides of the crust - stress is too much, crust can fracture - can cause sinkholes L6: Seafloor Spreading & Plate Tectonics Theory Seafloor Spreading Theory - by Harry Hess - occurs at mid-ocean ridges where tectonic plates diverge Magnetic Anomalies - Earth's magnetic field recorded in oceanic crust - reveal patterns of magnetic reversals Age of Oceanic Crust - younger, near to ridge - older, far to ridge Plate Tectonics Theory - explains how landforms are created - convection currents in the mantle is the cause of plate movement Continental Drift Theory - by Alfred Wegener - continents move, that were once together (Pangaea) + 2 Types of Crust: 1. Continental - less dense - made of granite 2. Oceanic - denser - made of basalt Plate Boundaries - the edges where two plates meet 1. Convergent - collide with each other - subduction zone (one or both oceanic crust) 2. Divergent - plates move away from each other  - water or magma fills the space 3. Transform - plates slide past each other L7: Ocean Basin Ocean - composed of salt water - covers nearly 70% of Earth - larger and deeper than sea Sea - part of ocean - bordered by land + 5 Ocean Basins (largest-smallest): 1. Pacific 2. Atlantic 3. Indian 4. Southern (Antarctic) 5. Arctic + Ocean Basin Structure a. Coastal Plain - flat, low-lying land adjacent to sea coast b. Continental Shelf - adjacent to a continent c. Continental Slope - between outer edge of continental shelf and deep ocean floor d. Continental Break - between continental slope and shelf e. Continental Rise - base of continental slope f. Abyssal Plain - “abyss” (very deep) - small elevated landform that rises from the depths of ocean g. Seamounts - large submerged volcanic mountain h. Guyots - flat top seamount i. Volcanic Arc - chain of volcanoes above a subducting plate + Evolution of Ocean Basins The Wilson Cycle - opening and closing ocean basins - uses plate tectonics  The 6 Stages: 1. Embryonic - uplift caused by rising magma 2. Juvenile - widening of rift valleys that connects to the ocean 3. Mature - continued lateral spreading, additional oceanic crust is generated 4. Declining - subduction around the border of ocean basin 5. Terminal - the ocean basin closes through subduction and eventually collide 6. Suturing - collision and intervening sea is gone L8: Rock Layers Absolute Dating - exact age of rock Relative Dating - compares the age from other rock  Stratigraphy - branch of geology that deals with stratified rocks on and within the Earth Stratification - also known as bedding - layering in sedimentary and igneous rocks from lava/volcanic activities Stratified Rocks - also known as derivatives rocks - may be fragmental/crystalline - product of sedimentary processes Laws of Stratigraphy: 1. Superposition - oldest, largest & heaviest settled first at the bottom - younger, lightest & smallest settled last 2. Original Horizontality - flat layers - maintains horizontal layers, not yet disturbed 3. Inclusion - contains pieces of rocks - older, rock inside of new rock layer (Rock A) - younger, the new rock layer that contains rock (Rock B) 4. Cross Cutting Relationship - younger, fault/magma intrusion that cuts through the rock layers - dike/dyke, sheet of rock that is formed in a fracture of pre-existing rock 5. Faunal Succession - different strata contain animal fossils based on depth - “flora” (plant), “fauna” (animal) 6. Unconformities - “conformable” (without disturbance) - deformed or eroded before another deposition that leads to rock layer mismatching a. Disconformity - erosion between two packages of sediment (parallel) - not tilted  b. Angular Unconformity - has been tilted c. Nonconformity - separate igneous/metamorphic rocks from sedimentary rocks L9: Earth's History Geologic Time Scale - record of life forms and geological events International Union of Geological Sciences (IUGS) - caused by evolution or extinction + Eons + Eras + Period + Epoch James Hutton - Theory of the Earth (book) - Father of Modern Geology William Smith - fossils are found buried in a definite order (strata) a. Rock Layers - past event that is preserve in rocks b. Fossils - evidence of pre-existing organisms (preserved skeletons) c. Radioactive Dating - natural radioactive decay of certain elements (half-life) Eons - infinitely long period of time A. Hadean Eon (4.6-4 BYA) - “Hades” (god of the underworld) - HOT!, heat comes from accretion, radioactive elements, and bombardment of meteorites - “Giant Impact Hypothesis” (Theia—Mars-sized collided with proto-Earth that formed the moon) B. Archean Eon (4-2.5 BYA) - beginning or origin - starting to cool down - oldest rocks - formation of continents and oceans - beginning of life - “Primordial Soup Hypothesis” (oceans were filled with chemicals important for life) - Miller Urey Experiment - oldest fossils of prokaryotes (photosynthetic) - Stromatolites (layer of rocks) - microbial reefs by cyanobacteria - production of Oxygen - O2 concentration begin to rise - near the Oxygen Revolution C. Proterozoic Eon (2.5-0.541 BYA) - earlier life - longest eon - continents & crusts stabilized - oxygenated atmosphere (O2 highly poisonous) - “The Great Oxygenation Event/Oxygen Catastrophe” (caused the extinction of anaerobic species) - buffers, metals present on the Earth that react or absorb the toxic O2 - banded iron formations as evidence - evolution of eukaryotes - “Endosymbiotic Theory” (mitochondria & chloroplast) + Ediacaran Period (635-542 MYA) - diverse algae and soft-bodied invertebrate animals (jellyfish, lichen, soft corals, etc.) D. Phanerozoic Eon (541 MYA - Present) - visible life - appearance of fossilized evidence a. Paleozoic Era (541-252 MYA) - ancient life + Cambrian Period (541-485 MYA) - major group (Phyla) of animals first appear - “Cambrian Explosion” - “Pikaia” (extinct primitive chordate animal) - “Algae” (plants were simple and one-celled) + Ordovician Period (485-443 MYA) - more soft-bodied animals (starfish, snails, clams, etc.) - “ground breaking” occurence: colonization of land by fungi, plants, and animals - microfossils of cells, cuticle, and spores - remains of early terrestrial arthropods Mass Extinctions - large percentage of species extinct - caused by climate change, geologic catastrophes, meteor strikes 1. Ordovician-Silurian Extinction (450-440 MYA) - 85% eliminated - 2nd largest extinction - glaciation and warming + Silurian Period (443-419 MYA) - diversification of fish and early vascular plants (Cooksonia) - moss-like miniature forests along lakes and streams + Devonian Period (419-358 MYA) - “Age of Fishes” - remarkable variety of fish (Placoderms—amongst first jawed fish) - millipedes, centipedes, and arachnids - small plants (tallest—1m tall) - ferns, horsetails, and seed plants - first trees and forest by the end 2. Devonian Extinction (375-360 MYA) - 80% eliminated - cause is lack of oxygen (anoxia) in the oceans - vascular plants trap carbon (CO2—important greenhouse gas) - cooling down the planet + Carboniferous Period (358-298 MYA) - coal-bearing - vast swamp forests - evolution of plants (lignin molecule) for wood and bark - insects grow in size due to high O2 - reign of predatory griffinflies - microbes that ingest lignin and cellulose (key wood eaters) that takes 60 million years to consume (lignin) - trees pile up - remove huge amount of CO2 - oxygen levels from 35%-21% - heat and pressure turn trees into coal + Permian Period (298-252 MYA) - Pangaea (massive continent) - Panthalassa (large ocean) - radiation of reptiles 3. Permian Extinction (251 MYA) - enormous volcanic activity (Siberia) - acid rain due to volcanic gases (CO2 & Methane) - highly acidic ocean - most extreme episode of volcanism b. Mesozoic Era (252-66 MYA) - middle life - time of the dinosaurs + Triassic Period (252-201 MYA) - cone-bearing plants (gymnosperms) - rise of dinosaurs that evolve and radiate - origin of mammals (small & nocturnal) 4. Triassic Extinction (205 MYA) - more than half eliminated - rising CO2 increased temperature and acidic oceans - massive volcanic eruptions along the margins of Atlantic Ocean + Jurassic Period (201-145 MYA) - warm, wet climate gave rise to lush vegetation and abundant life - gymnosperms as dominant plants - dinosaurs were abundant and diverse - diplodocus and stegosaurus existed - Archaeopteryx (transitional fossil between dinosaurs and modern birds) + Cretaceous Period (145–66 MYA) - last portion, “Age of Dinosaurs” - flowering plants (angiosperms) such as ficus, magnolia, and gingkoes  - Triceratops, Velociraptors, Tyrannosaurus Rex (T-Rex) 5. Cretaceous Extinction (65 MYA) - “K-T Extinction” - 75% died (including dinosaurs) - cause: major asteroid impact - formed the underwater Chicxulub crater - supporting evidence: elevated iridium levels - reduced light below Earth's surface - cooling down - no photosynthesis c. Cenozoic Era (66 MYA - Present) - recent life - “Age of Mammals” + Paleogene Period (66-23 MYA) - mammals diversified - left niches (ecological roles) - seed-bearing trees (angiosperms) - origin of primate groups (apes) + Neogene Period (23-2.6 MYA) - “new born” - origin of genus (Homo) - ancestor of humans (Hominins) during Ice Ages + Quaternary Period (2.6 MYA - Present) - cycle of glacial growth and retreat - extinction of large mammals and birds - spread of humans - Homo sapiens (300,000 YA) ✓ 176,000 - 11,000 - hunter-gatherer nomads ✓ 9,500 bce - 1825 - agricultural farming and settlements ✓ 1800 - 1500 - empires and conquests ✓ 1500 ce - 1778 - scientific revolution ✓ 1780 - 1945 - industrial revolution ✓ 1945 - Present - technological revolution 6. Holocene Extinction (11,650 YA - Present) - ongoing extinction - result of human activity