Earth Formation Hypotheses PDF

WEEK 1 It is when Earth accreted from materials of the HYPOTHESES EXPLAINING THE ORIGIN OF same composition after condensation. THE SOLAR SYSTEM 1. EVIDENCE...

WEEK 1 It is when Earth accreted from materials of the HYPOTHESES EXPLAINING THE ORIGIN OF same composition after condensation. THE SOLAR SYSTEM 1. EVIDENCES - It provides a mechanism that explains the presence of volatile elements in the core. BIG BANG THEORY AND THE RAISIN MODEL As the bread bakes, the raisins in the bread (like 2. LOOPHOLES - The hypothesis cannot explain the galaxies in our universe) don't change the the abundance of elements such as osmium, size, but the dough (the space between iridium, ruthenium, and rhodium in the mantle. galaxies) keeps getting bigger as the loaf rises. Singularity -The universe started as a “singularity​,” an area predicted to be in the core of a black hole with very high temperature and density. THE STEADY-STATE THEORY HETEROGENEOUS ACCRETION is another view that proposes that the universe when Earth accreted during condensation, has always been expanding. As the universe forming a differentiated planet as it grew in size. expands, new stars and galaxies are formed at the same rate that old ones become 1. EVIDENCE - It qualitatively explains the density unobservable due to distance and recession differences among terrestrial planets. velocity. 2. LOOPHOLES - Accretion must be very fast (103 Despite the continuous expansion, the average to 104 years for completion). This rate does not density of the universe remains the same; coincide with the occurrence of large impact craters. Also, the abundances of iron, calcium, hence, the name steady-state. titanium, and aluminum do not coincide with OSCILLATING UNIVERSE THEORY what was predicted by the theory. Oscillating universe theory, also known as pulsating theory, proposes that the universe is expanding and will contract once all the energy after the big bang has been used up. Then, it will expand again once it approaches the point of EARTH AND EARTH'S SUBSYSTEM singularity. SYSTEM THE BIG CRUNCH - The oscillating universe is - an interconnected set of components that a combination of big crunch and big bang, it are linked through interconnections that occurs the universe expands and eventually function to create an outcome. reverses, then collapses, causing the formation EARTH’S SYSTEM of a singularity. Once the universe reverses and attains the point - movement or transfer of matter and energy of singularity, another universe will be born. and the processes involved with these transfers. HOW YOU EVER WONDERED HOW EARTH CAME CLOSED SYSTEM TO BE? - only energy is transferred or exchanged with Accretion leading theories about the formation its surroundings. Matter is not included. of planet Earth. OPEN SYSTEM a process that occurs when gravity attracts tiny - transfer and exchange of both energy and bits of matter towards an object. matter with the surrounding system. Accretion is the gradual increase in the size of EARTH'S FOUR SUBSYSTEM an object by the buildup of matter due to gravity. FIRST SUBSYSTEM: ATMOSPHERE - Greek roots atmos which means gas, and sphaira which means globe or ball. The most HOMOGENEOUS ACCRETION abundant gas is nitrogen (78.1%) of the  atmosphere. Oxygen( 20.9%), and Argon (0.9%). Lastly, Carbon dioxide and the rest of THIRD SUBSYSTEM: HYDROSPHERE - The hydrosphere is the sum of all water on Earth the gasses combined constitute( 0.1%.) and the water cycle that distributes it around the planet. Troposphere - The troposphere is the lowest layer of our atmosphere. Most clouds appear here and nearly all weather occurs in this lowest layer. Stratosphere - Ozone molecules in this layer absorb high-energy ultraviolet (UV) light from the Sun, converting the UV energy into heat. Mesosphere - Most meteors burn up in the mesosphere. The coldest temperatures in Earth's atmosphere, about -90° C (-130° F), are found near the top of this layer. Thermosphere - Inside the thermosphere, there is a layer of electrically charged atoms and molecules that FOURTH SUBSYSTEM: BIOSPHERE are formed in this distinctive layer which are called - “Zone of life” ions. That layer is the ionosphere - global ecological system integrating all living things and their relationship including their Exosphere - As you might imagine, the "air" in the interactions with the elements of the exosphere is thin, making this layer space-like. In fact, lithosphere, hydrosphere and atmosphere. air in the exosphere is constantly - though very BIOMES gradually - "leaking" out of Earth's atmosphere into outer - area classified according to the species that live space. in that location. SECOND SUBSYSTEM: GEOSPHERE 1. Aquatic - includes freshwater (ponds, lakes, - Geosphere comes from the Greek word geo rivers) and marine (ocean, estuaries). 2. Forest - can be tropical, temperate, boreal which means ground, Earth, or soil. forest and taiga. Each type of forest has - The geosphere is considered that portion of distinctive features dominated by grasses rather the Earth system that includes the Earth's than large shrubs or trees. interior, rocks and minerals, landforms and the 3. Desert - characterized by low rainfall processes that shape the Earth's surface. 4. Tundra - coldest of all biomes. Oblate Spheroid- shape of earth eyy 5. Grassland - made of rolling hills of various LAYERS OF THE EARTH grasses enough rain, but not to grow trees 1. Crust - outmost layer 2. Mantle - middle layer, and its upper layer is ROCKS AND MINERALS: PHYSICAL PROPERTIES more fluid than its lower layer. OF MINERALS 3. Core - is the innermost layer, and its outer layer 1. LUSTER - quality and intensity of reflected light is liquid, while its inner layer is solid. exhibited by the mineral. Metallic – generally opaque and exhibit a DISCONTINUITY resplendent shine similar to a polished metal. 1. Mohorovicic - boundary between crust and the upper mantle. Non-metallic – (glassy), silky, pearly, dull 2. Gutenberg - boundary between the lower mantle (earthy), greasy, among others. and the outer core. 2. HARDNESS - measure of the resistance of a mineral 3. Lehman - boundary between the outer and inner to abrasion. core 3. COLOR - can also display a variety of colors resulting from impurities and also from some geologic Sedimentary rock processes - Made up of pieces of other rocks, it begins as sediments in rivers and they are deposited in lakes - Streak (powdered form) and oceans, if it becomes buried it can compact 4. CRYSTAL FORM - reflects the supposedly internal together, lose water and become cemented to form structure of the mineral. rocks. (e.g sandstone,limestone, and shale) BONDING TYPES A. Clastic sedimentary rocks - formed from COVALENT - the strongest type of chemical accumulation of clasts: tiny pieces of broken rock & shells (e.g conglomerate, Breccia) bond. - Lithification - turns sediment into rock IONIC - second strongest type - ( Deposition - Compaction - Cementation ) METALLIC - weakest type of chemical bond. B. Chemical sedimentary - formed when dissolved minerals precipitate from a solution (e.g halite, CLEAVAGE AND FRACTURE selenite, limestone) - property of some minerals to break along specific planes of weakness to form smooth, C. Organic sedimentary - formed from the flat surfaces. accumulation of plants or animals Coal - composed of organic matter in the form of CHEMICAL COMPOSITION OF MINERALS plant fragments SILICATES - minerals containing 2 of the most abundant elements in the Earth’s crust, namely, Metamorphic rock (metamorphism) - When rocks changed due to extreme heat or pressure silicon and oxygen. - subjected to great heat or pressure and transform into OXIDES - minerals containing Oxygen anion metamorphic rock. The most common types are (O2) combined with one or more metal ions (slates, schists and gneisses.) SULFATES - minerals containing Sulfur and Oxygen anion (SO4) combined with other ions Exogenic process SULFIDES - minerals containing sulfur anion - geologic processes initiated by forces emanating from (S2) combined with one or more ions. Some the Earth’s atmosphere, biosphere, and hydrosphere. sulfides are sources of economically important - geological phenomena and processes that originate externally to the Earth's surface. metals such as copper, lead and zinc. Weathering CARBONATES - minerals containing the - processes that break up and corrode solid rocks, carbonate anion (CO3) combined with other transforming them into sediments. elements 1. Physical Weathering (mechanical weathering) - HALIDES - minerals containing halogen process which breaks large masses of rocks into elements combined with one or more elements smaller grains or chunks. NATIVE MINERALS - exist in nature Factors: uncombined with anything else and contain Pressure & Temperature - Rocks cracks when subjected to pressure. Rocks expand and are atoms of only one type of element. fractured when exposed to high temperature. Frost wedging - Generally, rocks have fractures in its surface and when water accumulates in the crack and Week 2: at that point freezes, the ice expands and breaks the rock apart. Classification of Rocks 1. Water collects in rock crack 2. Water freezes forcing crack to widen Igneous rock 3. Ice thaws, contracts & water gets deeper into - Formed from cooling of magma & When molten cracks rock or magma crystallizes and solidifies. 4. Repeated expansion & contraction causes 2 types: further cracks till rock splits 1. Intrusive (plutonic) Abrasion - The breakdown of rocks is caused by - Cools on the inside of the earth’s crust impact and friction. This primarily occurs during - E.g (granite) collision of rocks, sand, and silt due to current or 2. Extrusive (volcanic) waves along a stream or seashore causing sharp - Develops after expelled from the earth edges and corners to wear off and become rounded. - E.g (basalt)  Week 3: Organic Activity/ Root Wedging - The roots grow causing penetration into the crack, expand, and in the Endogenic Process long run, break the rock. Burrowing animals - Animals like rats, rabbits and squirrels excavate into the ground to create a space Endogenic Process for habitation. - Geological process that was formed, originated, Chemical weathering - chemical reactions that and located below the earth’s surface change or destroy minerals when rocks are exposed How is magma formed to water and air. - Formed under certain circumstances in a special Dissolution - It occurs in specific minerals which are location deep in the crust or in the upper mantle. dissolved in water. Examples of these minerals are Magma forms from PARTIAL MELTING of Halite (NaCl) and Calcite (CaCO3). This chemical mantle rocks. reaction brings about the formation of stalactites and stalagmites in caves. Decompression Melting Hydrolysis - minerals react w/ water, broken down - Takes place within earth when a body of rock is into their constituent ions. held at approximately the same temperature but Oxidation - It is the response of oxygen with the pressure is reduced. minerals. If the iron oxidizes, the mineral in rocks - Occurs when pressure decreases but decomposes. Rusting is an example of this chemical temperature remains constant. reaction. Mantle Plume Erosion - the separation and removal of weathered - Column of hot molten rock in the mantle. rocks due to different agents like water, wind, and Continental Rift glacier that causes transportation of the material to where they are deposited. - Thinning process of the lithosphere ultimately leading to the rupture of the continent and the Mass Wasting formation of a mid-oceanic ridge and sea-floor - The movement of sediments downslope under the spreading. influence of gravity. Mid-ocean ridge - The examples of this are fall, slide, avalanche, and - seismically active submarine ridge system flow. situated in the middle of an ocean basin and marking the site of the upwelling of magma associated with seafloor spreading. Flux Melting - Rock is close to its melting point and some volatiles (water or carbon dioxide) is added to the rock, the melting temperature is reduced and partial melting starts. - Volatiles (easily evaporate at relatively low temperature) such as water and carbon dioxide help break chemical bonds in minerals, which lowers the melting temperature of the material. Rock Cycle What happens after magma is formed? - process of rock formation where interrelated events - Magma escapes in 2 forms happen one after another, they occur in succession 1. Intrusion: magma that moves up into a and can be repeated again. volcano without erupting. causes the - Structure of rock cycle: magma - igneous - volcano to grow on the inside. sedimentary - metamorphic 2. Extrusion: eruption of magmatic materials that causes land formation on the surface of the earth. Causes the formation of volcanoes when the gas pressure is strong enough & there are cracks in the earth’s crust. The deeper the magma chamber, the stronger the explosion.  - Plutonism: all sorts of igneous geological a glacier that has passed over the surface. activities taking place below the earth’s surface. Evidence from fossils - Volcanism: geological phenomena that occur -A lot of fossilized life found in the rock records on the natural terrestrial surface, e.g creation of did not fit in the climates they were found in. volcanoes and hot springs. Ex: Rocks in Alaska contain fossilized - Molten Material in the form of lava that palm tree leaves, which are uncommon undergoes the process of crystallization in that latitude today. on the natural terrestrial surface gives Evidence from rock formations birth to rock formation known as volcanites Structures produced by deformation - Faults: zone of fractures between two blocks Shapes or types of volcano of rock. Faults allow the blocks to move relative - Shield Volcano: Low with gently sloping sides to each other. classified based on the movement - Broad volcanoes with gentle slopes and are of rocks with respect to one another. shaped somewhat like a warrior’s shield lying flat on Earth. - Cinder cone volcano: a bowl-shaped crater at the summit and steep sides. - smallest type of volcano - Composite Volcano: tall, cone shaped Types of faults volcanoes that produce explosive eruptions 1. Normal fault - The hanging wall moves down concerning the Types of stress that affect the behavior of rocks footwall. caused by extensional force - Compression: type of stress that squeezes and 2. Reverse fault shortens a body such as rocks. - The hanging wall moves up for the footwall. - Tension: the type of stress that stretches and caused by compressional force. pulls a body apart. 3. Strike-Slip Fault - Shearing: can cause masses of rock to slip, - two blocks slide past each other. caused by the type of stress that distorts a body by pushing shearing force. parts of the body in opposite directions. Types of folds Analyzing the formation of folds and faults due to Folds the movement of plates - Produced by the deformation of ductile - Alfred Wegener: He is a German scientist who materials (flexible) suggested in the early 1990s the theory that the - Contortions of rock layers forming wavelike continents once shaped a single land mass then curves. broke-up and glided to their present positions. Hinge line or fold axis - Hypothesis of Continental Drift Theory - Part of the fold where curvature is greatest. “Pangea” means “all earth.” “supercontinent Limbs - First split into two huge land masses called - Sides of the folds. Laurasia and Gondwana. Anticline -An anticline is a fold that is arched upward to Evidences for Continental Drift: form a ride pieces of a jigsaw puzzle. Syncline Ex: The coast of Africa fits well with the - A syncline is a fold in which the youngest eastern coast of South America and southeast layer is in center of the fold. Synclines are coast of North America. commonly bowl-shaped. Distribution of Global striations Monocline - He plotted in the map the locations of the - A monocline is a fold in which both limbs are sediments and rocks that were formed during horizontal or almost horizontal. It is formed when the last glaciation of the late Paleozoic. one part of Earth’s crust moves up and down Global Striations: long, straight, parallel lines relative to another part. or grooves in a bedrock surface, formed by boulders, gravel, and pebbles embedded in  Week 4: Sea-floor Spreading - Arthur Holmes - a British geologist who Deformation of Crust pioneered radiometric dating of minerals, supported the theory of Pangea but attributed and History of the Earth the mechanism for this movement to the convection cells from within the earth’s mantle Plate - one of 7 major distinct pieces of abt 7 major Stages of Sea-floor Spreading distinct pieces of relatively rigid lithosphere 1. Embryonic stage - Has 7major plates and 8minor plates - The first stage of ocean basin info, is where rift Tectonism valley creation results from the splitting of the - Deformation of the lithosphere, continents. E.g Great rift valley & eastern Africa - (tectonics) is the study of this deformation Plate Tectonics Theory - theory that Earth's outer shell is divided into 2. Juvenile stage large slabs of solid rock, called “plates,” that - Ocean basin formation and narrow seas with glide over Earth's mantle, the rocky inner layer matching coasts are created. This technique is above Earth’s core. what created the Red Sea. - asthenosphere — a dense layer kept malleable by heat deep within the Earth. It lubricates the undersides of Earth's tectonic plates, allowing the lithosphere to move around. 3. Mature stage - Ocean basin experiences broadening, trench Plate Boundaries formation, & the beginning of subduction during - where plates meet and, as expected, friction, the mature stage E.g Atlantic Ocean sliding, and collision happen along the boundary. 1. Divergent boundaries - Also called (spreading boundaries), move apart from each other. 4. Declining stage 2. Divergent boundaries - Continues subduction, ocean’s bottom & ocean - Below sea level: mid-ocean ridge. ridge are being removed. E.g Pacific Ocean - Above sea level: Rift Valley. 3. Convergent boundary - Also called convergent margin, where 2 plates meet. 5. Terminal stage A. Oceanic & Continental - uplift and convergence cause the basin to - Oceanic is denser so it goes under the narrow and become shallow. Young continental where it sinks into the subduction mountains may form along the edges due to zone sediment buildup. E.g Persian Gulf B. Oceanic & Oceanic - the older plate goes under, rising magma breaks out of the plate above, where it forms a volcanic arc. 6. Suturing stage - Sea mounts — volcanic arc that isn’t active - continents collide, transforming young - Volcanic Island arc — chain of islands/volcano mountains into mature ones. After the seafloor - Marianas in the South Pacific - island chain is destroyed and the continents collide, a - Philippine and Pacific plates - oc oc chain of continental mountains is formed. C. Continental & Continental - Older plate sinks beneath - E.g the Himalayan mountain range stretches along the border between India and Tibet. NOTE: Young rocks can cut across other rock layers Week 6: (older) - All atoms of an element have the same number Marine and Coastal of protons. Processes Isotopes - The atoms of an element that have different Marine Processes numbers of neutrons. - Waves occur when the force of the wind blows - Can be stable and unstable. over surface water, transferring its energy and A. Unstable Isotopes causing the water to move in a circular motion. - Can break down into new isotopes of The rise and fall of water molecules creates a different elements. wave that moves in the direction of the wind. - Also called radioactive isotopes. The wave transports energy, not water. - When these radioactive isotopes break Waves down into new isotopes, radioactive - The swash is when a wave washes up onto the decay occurs. shoreline and the backwash is when the water Radiometric Dating from a wave retreats back into the sea. - A process to determine the correct age Two types of waves of an object. Constructive wave - Scientists can find out the age of a rock - The swash is stronger than the backwash. by studying the ratio of parent and - Constructive waves are low energy waves that daughter isotopes in it. result in the build-up of material on the - To use radiometric dating, you have to shoreline. know the half-life of the parent isotope Half-life - How long it takes for half of a sample of the isotope to decay. - Ex: A parent isotope that has a mass of 12g has a half-life of 10,000 years. Carbon-14 method - Carbon-14 has a short half-life of only Destructive waves about 5,730 years. Accordingly, this - Destructive waves have stronger backwashes method can be used to date the remains than swashes. This strong backwash pulls of organisms that died in the last 50,000 material away from the shoreline and into the years. sea resulting in erosion. Geologic time scale Period - The concept of a geologic time scale is that a “period” is a basic unit of geological time during which a specific kind of rock system is produced. - Epoch - Some “periods” have their own subdivision; these three geologic subdivisions are called “epochs.” 1. Coastal Erosion Era - It is the loss or displacement of land along the coastline - When "periods" are compacted together due to the action of waves, currents, tides, wind-driven according to their characteristics, this geologic water, or other impacts of storms. Coastal erosion is a division will comprise the so-called "era." type of coastal hazard which is brought about by the - Eon - When "eras" are grouped together, this different coastal processes. will create the longest geologic subdivision Types of Erosion called an "eon." Abrasion - This is where breaking waves throw rock fragments against the cliffs slowly wearing away the cliff material. Hydraulic Pressure - happens through the forces of the waves hitting a coastline and trapping air into cracks and joints on the face of a cliff. Solution - This is when sea water dissolves some chemicals in certain types of rocks. Attrition - The process of erosion that occurs during rock collision and transportation. Wave Scouring - waves breaking at the base of the cliffs swirl around the base and cause the elimination of movable rock. Wave Pounding - collapse of the cliff face because of the absolute force of a wave which can wield up to 30 tonnes/m^2 when crashing on the cliffs. - As heavy as a bulldozer 2. Saltwater Intrusion - Saltwater intrusion is the induced flow of seawater into freshwater aquifers primarily caused by groundwater development near the coast. 3. Submersion - Submersion refers to events that cause coastal areas and even islands to be completely covered by ocean water, usually during powerful storms like hurricanes. - It refers to the movement of coastal sediments from the visible portion of a beach to the submerged nearshore region of the coast. Mitigation - reducing risk of loss from the occurrence of any undesirable event.