Earth Science Chapter 4 Plate Tectonics PDF
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This document contains information on plate tectonics and earth science. It covers topics such as the Earth's interior, layers, and plate movement. The content includes diagrams and summaries of different types of plate boundaries, making it a useful resource to expand an understanding of earth science.
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Earth Science Chapter 4 Plate Tectonics Do Now What layers of the Earth make up the tectonic plates? What causes tsunamis? Earth's Interior The three main layers of Earth are the crust, the mantle, and the core. Layers of the Earth are similar to the laye...
Earth Science Chapter 4 Plate Tectonics Do Now What layers of the Earth make up the tectonic plates? What causes tsunamis? Earth's Interior The three main layers of Earth are the crust, the mantle, and the core. Layers of the Earth are similar to the layers in a hardboiled egg!! How do scientists study and gather evidence about the different layers of Earth's interior without being able to directly access them? During earthquake different type of seismic waves are formed.P waves travel through solid and liquid while S waves travel through solids.Geologist record the seismic waves and their path reveals the makeup of earth’s interior. Layers of the Earth Lithosphere: Includes the Earth’s crust, as well as the solid, rocky part of the upper mantle. This forms the tectonic plates. Asthenosphere: This is the material that the tectonic plates float on and is the semi-molten part of the upper mantle. Mantle: This is made of molten rocks called magma and is 1,600-4,000 degrees Fahrenheit. Mantle forms 80% of the Earth’s volume Outer Core: This is made of molten metals, which are nickel and iron. The temperature of these metals is 4,000-9,000 degrees Fahrenheit. Inner Core: This is made of solid metals, which are nickel and iron. The temperature of these metals is 9,000 degrees Fahrenheit. Earth’s Crust Oceanic crust & Continental crust is less dense than the mantle and “floats” on top of the mantle.Oceanic crust is thinner but more dense than continental C. Typically, oceanic crust is composed of the more dense igneous rock, basalt. The continental crust is composed of the less dense granite. When they collide, the oceanic crust sinks below the continental crust. Convection and the Mantle There are three types of heat transfer: radiation, conduction, and convection. Convection currents move because hotter material is less dense than cooler material and will rise/float. Cooler material is more dense & sinks. Continental Drift Wegener's hypothesis was that all the continents were once joined together in a single landmass and have since drifted apart. Alfred Pangaea – the Wegener super continent Evidence of Continental Drift Alfred Wegener identified: 1. Continents fit together like the pieces to a puzzle 2. Fossil evidence of dinosaurs and prehistoric plants 3. Geologic rock and sediments Pangaea This was the super continent that existed more than 2,080 million years ago. In Greek it means “all land”. Pangaea was surrounded by one big ocean: Panthalassa. The continents that made up Pangaea started to move, forming two separate landforms: Laurasia (North) and Gondwana (south). These landforms continued to separate into the seven separate continents we know today. This movement didn’t happen overnight. The continental drift was caused by the movement of the tectonic plates, which was very slow (about 2cm per year). The Theory of Plate Tectonics The theory of plate tectonics explains the formation, movement, and subduction of Earth's plates.It is a very slow process 2 cm in a year. Plate Boundaries There are three kinds of plate boundaries: Divergent: spreading boundaries Convergent: colliding boundaries Transform: sliding boundaries. Divergent Boundaries The place where two plates move apart. Molten magma fills in and creates new crust. Sea Floor Spreading: most spreading boundaries occur at the mid-ocean ridge (stretches around the world). A deep valley called a rift valley forms along the spreading boundary. (Ex. African Rift Valley, Red Sea) O-O (Oceanic Crust to C-C (Continental Crust to Oceanic Crust) Continental Crust) Mid-Ocean Ridges Rift Valley Divergent Boundaries Red Sea Mid-Ocean Ridge Convergent Boundaries Continental – Continental Oceanic – Oceanic Continental - Oceanic Convergent Boundaries Continental - Continental: Two plates buckle and create folded mountains. (ex. Indian Plate and Eurasian Plate form the Himalaya Mountain Range) Oceanic - Continental: The oceanic crust is denser causing it to subduct and form trenches. The plate later melts, causing magma to form. This magma then rises to form a volcano. (ex. Mariana Trench in Pacific Ocean) ,islands and oceanic trench marking the plate boundaries. Oceanic - Oceanic: More dense and older plates subduct under younger plates, trench and creating volcanic island arcs. (ex. Hawaiian Islands) Convergent Boundaries Oceanic – Oceanic Continental – Continental Oceanic – Continental Transform Boundaries The plates slide past and scrape against each other, causing earthquakes and forming faults. This process does not form magma. The San Andreas fault, located in California Transform Boundaries Faults are fracture zones between two rocks. In a normal fault, the hanging wall block moves down due to tension and pulls the rock apart. In a reverse fault, the hanging wall block moves upwards due to compression and the pressure squeezes the rock together. (ex. Rocky Mountain Range that goes from northern Canada down southward towards New Mexico, U.S.) In a strike slip fault, the plates pass horizontally against each other in the opposite direction. (ex. San Andreas Fault, located in California) Volcanic Hot Spot https://www.youtube.com/watch?v=QO2OO1r_tFg &pp=ygUdd2hhdCBjYXVzZXMgdm9sY2FuaWMgaG 90c3BvdHM= Hot spot Hot spots are areas in the Earth's mantle where unusually high temperatures cause magma to rise and create volcanic activity on the surface, often far from tectonic plate boundaries. Found beneath both oceanic and continental crust. They are stationary relative to the moving tectonic plates above them. As tectonic plates move over a hot spot, it creates a series of volcanoes or volcanic islands. Older volcanoes move away from the hot spot and become dormant, while new ones form above it. e.g Yellowstone Hot Spot (USA) Ring of Fire The horseshoe shape contains 700-900 active or dormant volcanoes that stretch around the edge of the Pacific Ocean, including the coast of North America, South America, Japan, Philippines, Australia, New Zealand, and Antarctica.