MTTC Integrated Science - Earth & Space Sciences Exam Questions & Answers

Theory of Plate Tectonics - Answer A theory stating that Earth's lithosphere is broken into huge plates that move and change in size over time - explains the process of continental drift - theory is a fusion on the theories of continental drift and seafloor spreading - continents are not floating on the ocean, rather they are rooted What are the 10 major plates of the Earth's lithosphere? - Answer African, Antarctic, Australian, Eurasian, North American, South American, Pacific, Cocos, Nazca, and Indian. What are the two main sources of tectonic plate motion? - Answer gravity and friction What is the source of energy for tectonic plate motion? - Answer the dissipation of heat from the mantle in the (relatively weak) asthenosphere ridge push - Answer when the force of gravity moves a plate downward and away from a ridge slab pull - Answer a mechanism that contributes to plate motion in which cool, dense oceanic crust sinks into the mantle and "pulls" the trailing lithosphere along mantle drag - Answer plates move due to the friction between the lithosphere and the asthenosphere trench suction - Answer involves a downward frictional pull on oceanic plates in subduction zones due to convection currents convergent plate boundary - Answer when adjacent plates move toward one another and one plate slips underneath another. three types of formations can come of this 1) oceanic plate + oceanic plate = deep trench 2) continental plate + continental plate = mountain 3) continental plate + oceanic plate = ocean goes under continent, mountains on one side, oceanic trench on the other subduction zone - Answer the region where an oceanic plate sinks down into the asthenosphere at a convergent boundary, usually between continental and oceanic plates divergent plate boundary - Answer when two adjacent plates move away from one another. the lithosphere cracks, pushes molten magma through the cracks, the magma cools, and new crust is formed. two types: 1) ocean + ocean = oceanic ridge systems 2) continent + continent = rift valleys transform plate boundary - Answer When two plates slide past one another cause: earthquakes when they snap past one another also called "strike-slip faults" geologic fault - Answer a fracture in the earth's surface created by movement of the crust. most are found on tectonic plate boundaries. three types: 1) normal fault 2) reverse fault 3) strike-slip fault normal fault - Answer A type of fault where the hanging wall slides downward; caused by tension in the crust reverse fault - Answer a type of fault where the hanging wall slides upward; caused by compression in the crust. steep dip strike-slip fault - Answer a type of fault where rocks on either side move past each other sideways with little up or down motion Geologic folding - Answer a region of curved or deformed stratified rocks. rock strata are normally formed horizontally, so when they are found vertically formed, it is clear that geologic folding took place anticlines and synclines - Answer Anticlines are upward arching folds with older rocks near the core of the fold synclines are downward arching folds with younger rocks near the core of the fold Orogenesis - Answer The process of mountain building that occurs when large-scale compression leads to deformation and uplift of the crust; literally, the birth of mountains. folded mountains - Answer form from the long-term deformation and metamorphosis of sedimentary and igneous rocks. usually occur in chains and form at convergent plate boundaries faultblock mountains - Answer occur at normal or reverse faults with high dips where portions of the Earth's crust are displaced along the faults oceanic ridges - Answer formed at divergent boundaries beneath the ocean. when plates move apart, material from the mantle rises up and creates long mountain chains Volcanic Mountains - Answer form from the accumulation of products of volcanic eruptions, such as ash and lava. often occur singularly, unlike all other kinds of mountains which occur in chains. continental drift - Answer The hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations continental crust is also called? - Answer sial Thickness of continental crust - Answer 10-50 km thin continental crust is _____ thick continental crust is _____ - Answer thin is OLDEST OROGENIC ACTIVITY thick is NEAR PRESENT-DAY MOUNTAINS the two layers of the continental crust (and the space that separates them) - Answer upper layer: density 2670 kg/m3, granite, thermal energy related to the activity of radioactive elements SEISMIC VELOCITY DISCONTINUITY (8-10km below the surface) lower layer: density 3000 kg/m3, gabbroic properties, extremely variable oceanic crust is also called? - Answer sima thickness of the oceanic crust - Answer 5-10km overlay and the 3 igneous rock layers of oceanic crust - Answer Overlay: sediment (fossils, marine life, continental debris) first layer: 1-2.5km thick, basaltic lavas second layer: 5km thick, coarse-grained gabbroic third layer: thin (>0.5km), basalts age of oceanic and continental crust? - Answer oceanic: 200 million years old continental: several billion years old magnetic striping - Answer a pattern of alternating stripes of different directions of magnetic polarity in rock on the sea floor seafloor spreading - Answer The process that creates new sea floor as plates move away from each other at the mid-ocean ridges Earth's Layers - Answer 1) crust: 0-35km, basalt and granite 2) mantle: 35-2890km, rocky, temp 100-3500 C MOHOROVICIC DISCONTINUITY 3) core: km, liquid outer, solid inner, nickel and iron - outer km, inner km Lithosphere - Answer - the crust and the uppermost portion of the mantle of the Earth - located 0-60km below the surface - the cooling layer of the planet's convection cycle and it thickens over time - fragmented into tectonic plates and it floats atop the Earth's mantle - oceanic lithosphere - basaltic rocks, thinner, denser - continental lithosphere - granite sedimentary rocks, thicker, less dense Asthenosphere - Answer - the soft layer of the mantle on which the lithosphere floats - located 100-700km below the surface - heat and pressure keeps the composite material plastic Mesosphere (earth layer) - Answer - the strong, lower part of the mantle between the asthenosphere and the outer core - located 900-2800km below the surface the rock cycle - Answer an idealized cycle of processes undergone by rocks in the earth's crust, involving igneous intrusion, uplift, erosion, transportation, deposition as sedimentary rock, metamorphism, remelting, and further igneous intrusion. igneous rocks - Answer formed when magma cools and hardens on the Earth's surface (extrusive igneous rocks) or when magma cools inside the earth's interior (intrusive igneous rocks) ex: obsidian sedimentary rocks - Answer Formed when particles of broken rock and organic materials are pressed and cemented together (lithification) to form new rocks. Sediments are mud, sand, pebbles, shells, bones, leaves, and stems. Some rocks of this type can be sandstone, limestone, and gypsum. metamorphic rocks - Answer Made when heat, pressure, or fluids change one type of rock into another type of rock plate tectonics rock cycle - Answer new oceanic lithosphere is created at divergent plate boundaries. this new crust spreads outwards until it reaches a subduction zone where it is pushed back into the mantle, becomes magma, and is thrust out into the atmosphere. then it experiences erosion and becomes sedimentary rock. at convergent plate boundaries this crust becomes involved in mountain building and the associated metamorphic pressures, until it is eroded again and returns to the lithosphere. the role of water in the rock cycle - Answer - erosion and weathering - carries ions and sediments to basins where they will be compressed into sedimentary rock - contributes to the dissolution of rocks and minerals - metamorphic process that occur underwater - melting of rocky crust into magma at subduction zones Metamorphism - Answer an isochemical process in which one type of rock changes into metamorphic rock because of chemical processes or changes in temperature and pressure effect of heat in metamorphism - Answer - when extreme heat is applied to existing rock, their component minerals are able to recrystallize - high levels of thermal energy may cause rocks to contort and deform