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Earth Science Geology Dynamic Earth Review Name __Key___________ Date______________ Class______________ Directions: Please use your notes, work sheets, and “schoolnotes page” links to complete the following. These are the concepts you should be most familiar with and should study for the summative. The date of the summative is _May 30________________! Crust – two types – Continental and Oceanic – 1. Layers and make-up of the Earth: Continental is less dense (granite) – floats higher on the Mantle, Oceanic is more dense (basalt) – All crust is a. label and describe! high in silicon, a low density mineral, Difference between basalt and granite is the size of the crystal – basalt cools fast – small crystals, granite cools slowly – larger crystals Mantle – plastic-like; convection currents occur here; high in iron (Fe) – very dense Outer core – Very dense Nickel (Ni) and Iron (Fe) – Mostly fuid-like – high pressure HOT Inner Core – Pressure causes core to be VERY HOT and solid – Composed of Ni and Fe. Causes Magnetic poles b. What are the minerals that make up each layer? Crust – silicates – Silicon and Oxygen Mantle – Iron, Magnesium, Silicon, Oxygen Core – Iron, nickel 2. Plate Tectonics: What is it? Why is it important? Plate Tectonics explains that the Earth is made up of rigid slowly moving pieces or plates. The plates are a combination of the Crust and the Lithosphere. There are 8 major plates and many minor plates. a. What landforms can we find at each type of boundary and what type of motion do we see? b. Divergent: Mid-Ocean Ridge – creates new plate material – Occurs between the N. American plate and the Eurasia Plate. Magma bubbles up between plates push the plates apart. The older material is found further away from the ridge. Minor Earthquakes Rift Valley, creates mountain due to volcanic activity, occurs where two continental plates are spreading apart. The only one we have currently is between the African plate and the Arabian Plate. Earthquakes and volcanoes occur here. c. Convergent: Subduction of Oceanic plate occurs – Oceanic plate is more dense than continental; trenches re formed where the plate goes under. Behind the subduction zone you commonly find volcanic mountains. – Example: found where the Nazca plate subducts under the S. American Plate. Deep earthquakes, Strato-Volcanoes – Pyroclastic. Subduction of one oceanic plate under another – trenches with volcanic islands are formed – example – Pacific plate subducting under the Indo-Australian Plate. – Deep Earthquakes and volcanoes Colliding plate do not subduct due to the density of the crust material (mantle pushes them up); folding occurs here; mountains are created; lots of granite; Example: Arabian plate and Eurasian Plate – Himalayan mountains. Earthquakes are common here. d. Transform: Faulting occurs here as plates slide past each other. Friction holds the plates together for a period of time and then they move suddenly past each other. Major damage can be seen on soft ground – Example – Haiti (Caribbean plate and S. American plate) c. Is there evidence of plate tectonics in Connecticut? Where? Give specific evidence! The Western part of the state was part of a collision zone millions of years ago, creating enormous mountains. The Central CT valley was a rifting zone and nearly became to location of the Atlantic Ocean. For some reason this rifting stopped and moved to the East. This created the valley we live in. 3. Pangaea: a. What is it? – A large super continent that existed millions of years ago – there may have been other supercontinents as well. b. What evidence do we have that it really existed? – We have fossil evidence, glacial evidence, and we can see that the shape of the continents fit together a bit like a puzzle. c. What does this map tell us? This map shows fossil and shape evidence for Pangaea. 4. Sea-floor Spreading and continental drift: a. What is it? The process of tectonic plates moving apart and creating new oceanic plate material. b. What evidence it there? Older plate materials occur further from the zone. c. What does this diagram tell us? That the North American and Euraisian plates are moving further away from each other. Zone A is older than Zone B. This part of the plates is getting larger. d. What does this graph tell us? That the crust further from the Atlantic ridge is older than the crust closest to the Mid-Atlantic ridge. 5. Earthquakes and Volcanoes: Please fill in the chart! Question What causes them? Earthquakes Friction of two plates moving past each other. Plates ‘pop’ past each other – pressure release Volcanoes Crust materials in the Mantle floats to the top of the lithosphere – pressure builds and the fluid crust Where are they most likely found? At any plate boundary – some are deep earthquakes, some are more shallow Destructive or constructive force? Destructive Found at a convergent boundary – Oceanic or at a hot spot (an opening in the crust away from a plate boundary.) Volcanoes are both constructive and destructive – they create new land while Quick or slow force of nature? Quick changing the old land as well. Quick 6. Weathering: Fill in the chart with the facts from your reading, labs and notes! Chemical Pollution Acids/acid rain Dissolve the minerals in rock, Animal waste / animal action Root action Sand, wind, and rain Physical Cause opening in the rocks where water can enter and freeze. Acids from feces and Animals can burrow urine break down the around and in some minerals in softer rocks. cases into rocks…allowing water to seep in and freeze or carry away some of the mineral compounds. Plants secrete weak Plant roots start out acids that slowly small then increase in weaken/dissolve the size as the plant grows, rock. this pushes the rock apart causing fractures. Rain dissolves water Sand, Wind and rain soluble minerals carry smaller sediments that can cause abrasion of the rock. 7. Erosion: What is it? The movement of weathered material creating new landforms a. Fill in this chart on the 5 causes of Erosion: Gravity Water Wind Waves Ice Sediments Any Stones, Small Sand and Large Involved? sediment small sediments small boulder to Time frame? Types of landforms produced by removal of the sediments? is subject to the force of gravity. rocks, small sediment, sand – sand soil, very small stones Takes a very long time Cliffs, slopes Takes a very long time Rills, gullies, streams, river, valleys, alluvial fan Takes a very long time Dunes; loess Meanders, oxbow lakes, deltas, Dunes; loess Types of Slopes, landforms hills produced by the deposit of the sediments? sediments; is periods of large waves larger rock can be moved. Takes a very long time Sea arches, sea caves, sea stacks, wave-cut cliffs Beaches, spits Caused by longshore drift very small sediments. Methods – Plucking and abrasion Takes a very long time Glacial lakes, prairie pothole, horns, cirque, arête, Ushaped valley, drumlin Deposited till may create moraines, new islands (think Long Island), fjord b. What are some ways that erosion can be slowed or even prevented? Planting vegetation, placing heavier material on the lighter sediment (such as stone or rock 8. Glaciers: a, How are they formed? Formed when more snow falls than melts so snow builds up year after year. b. Five ways they shape the Earth? Plucking, abrasion, deposition, polishing c. When were glaciers covering the Northern United Sates? Up to 10,000 years ago glaciers retreated from North America What evidence of glaciers do you see in Connecticut? Where? Give specific examples! Long Island sound, CT River Valley, drumlins in Storrs, random sorting of till at Hammonasset. d. Glacier vocabulary: -plucking- as a glacier flows over the land it will pick up rocks that have broken off under the weight of the glacier -abrasion- wearing away of rock by sediment on the underside of the glacier. -till- mixture of sediment that a glacier deposits directly on the surface. -moraine- till deposited at the edge of a glacier on the surface -kettle – depression that forms when a chunk of ice is left in till and melts away. e. Describe calving: the process of a glaciar breaking off the end of a glaciar into the water. This creates icebergs. What is the purpose? Provides a source of freshwater, glaciers house the majority of the water found on Earth 9. Rock Types: a. What are they made of: Sedimentary – loosely packed minerals; rock formed under the pressure of the sediments above; formed layer by layer; layering can bee seen with the unaided eye Metamorphic – rock formed under immense pressure; sediment is compressed until the molecule fuse – these are new rocks; some show evidence of the original rock type (folding and faulting) Igneous – rock born of fire – made from cooled magma – rate of cooling effects density; slow cooling means a less dense rock (granite); faster cooling is a more dense rock (basalt) b. Produced 3 ways: Sedimentary – layers over time; pressure of overlying layers creates rock Igneous – created by cooling magma Metamorphic – high pressure – folding and faulting. c. Give examples of each type: Igneous – Granite and basalt Sedimentary – limestone, sandstone, and shale Metamorphic – marble and slate