Earth’s Interior Concept 2 Notes

How do Geologists Learn about Earth’s Interior? Geologist – someone who studies Earth’s rocks, structures, and landmassesGeologist – someone who studies Earth’s rocks, structures, and landmasses Unable to see deep inside of EarthUnable to see deep inside of Earth Deepest attempt was in 2011Deepest attempt was in 2011 Into a previously started drill site 2km into the ocean crust. (Ocean crust is thinner.) Its goal was to sample the lower crust of Earth. Read the article here: Into a previously started drill site 2km into the ocean crust. (Ocean crust is thinner.) Its goal was to sample the lower crust of Earth. Read the article here: types of evidence to learn about the interior –2 types of evidence to learn about the interior – DirectDirect IndirectIndirect

Rock Sample Evidence Direct MethodDirect Method Geologists have drilled 12.3 km (7.64 mi) into Earth’s crust (continental plate)Geologists have drilled 12.3 km (7.64 mi) into Earth’s crust (continental plate) Volcanoes shoot out rocks from inside of EarthVolcanoes shoot out rocks from inside of Earth Re-create early conditions of Earth in laboratory to see what original rocks may have been like.Re-create early conditions of Earth in laboratory to see what original rocks may have been like.

Evidence from Seismic Waves Indirect MethodIndirect Method Earthquakes createEarthquakes create Speed and path of seismic waves give geologist clues about the interior of Earth’s structure.Speed and path of seismic waves give geologist clues about the interior of Earth’s structure.

Features of Earth’s Interior Layers Interior Layers are: Crust, Mantle, CoreInterior Layers are: Crust, Mantle, Core The layers are different, but there are some rules that apply as you travel closer to the center of the Earth.The layers are different, but there are some rules that apply as you travel closer to the center of the Earth. The deeper down into Earth you go, the higher the pressure. This is due to the weight of the layers of rock above each other. The deeper down into Earth you go, the higher the pressure. This is due to the weight of the layers of rock above each other. The temperature inside of Earth increases as depth increases. Rock starts out cool near Earth’s surface, after 20 meters the rock is warmer, every 40 meters after that there is an increase in temperature by 1° C. The temperature inside of Earth increases as depth increases. Rock starts out cool near Earth’s surface, after 20 meters the rock is warmer, every 40 meters after that there is an increase in temperature by 1° C.

Features … (Cont.) Eventually the temperatures increase more slowly.Eventually the temperatures increase more slowly. The temperature increase or HEAT is due to the pressure and some of the leftover heat from the formation of Earth – 4.6 billion years ago. (Heat is trapped inside.)The temperature increase or HEAT is due to the pressure and some of the leftover heat from the formation of Earth – 4.6 billion years ago. (Heat is trapped inside.) Read me: -still-retains-much-of-its-.htmlRead me: -still-retains-much-of-its-.html -still-retains-much-of-its-.html -still-retains-much-of-its-.html

The Crust Rock layer that forms Earth’s outer “skin”Rock layer that forms Earth’s outer “skin” Solid rock that includes both dry land and the ocean floor.Solid rock that includes both dry land and the ocean floor. Main elements it contains are: oxygen and siliconMain elements it contains are: oxygen and silicon 5-40 Km thick5-40 Km thick thickest under high mountains (80 km !)thickest under high mountains (80 km !) thinnest beneath oceansthinnest beneath oceans Overall, the crust is the thinnest layer of Earth’s interior.Overall, the crust is the thinnest layer of Earth’s interior.

Oceanic Crust Under oceanUnder ocean Mostly composed of the rock, basalt, which is dark and fine-grained.Mostly composed of the rock, basalt, which is dark and fine-grained.

Continental Crust Forms the continentsForms the continents Contains many types of rocks, but overall it is much like granite, which is light in color and has coarse grains.Contains many types of rocks, but overall it is much like granite, which is light in color and has coarse grains. Both granite and basalt have more O and Si than any other elements.Both granite and basalt have more O and Si than any other elements.

The Mantle Layer of hot rockLayer of hot rock 3,000 km thick3,000 km thick Divided into three parts based on their physical characteristicsDivided into three parts based on their physical characteristics LithosphereLithosphere AsthenosphereAsthenosphere MesosphereMesosphere

Lithosphere Uppermost part made of brittle (easy to break) rockUppermost part made of brittle (easy to break) rock Strong, hard, rigidStrong, hard, rigid Grouping the crust and the uppermost mantle together you get the lithosphere = 100 km thickGrouping the crust and the uppermost mantle together you get the lithosphere = 100 km thick

Asthenosphere Hotter material under increasing pressureHotter material under increasing pressure Can bend (like metal)Can bend (like metal) Still solidStill solid

Mesosphere Hot but more rigid than the asthenosphereHot but more rigid than the asthenosphere Stiff due to increasing pressure.Stiff due to increasing pressure. Includes the transitional zone which is just below the asthen.Includes the transitional zone which is just below the asthen. Includes lower mantle that extends into Earth’s core.Includes lower mantle that extends into Earth’s core.

The Core Made of mostly iron and nickel with 2 parts.Made of mostly iron and nickel with 2 parts. Outer Core (liquid) – layer of molten metal surrounding the inner core.Outer Core (liquid) – layer of molten metal surrounding the inner core. 2,258 km thick 2,258 km thick Inner Core (solid but molten)– Dense ball of solid metal due to the extremely intense pressure in the inner core, iron and nickel atoms cannot spread out enough to become solids.Inner Core (solid but molten)– Dense ball of solid metal due to the extremely intense pressure in the inner core, iron and nickel atoms cannot spread out enough to become solids. 1,222 km thick1,222 km thick There is some data to suggest that along with the metals, there is oxygen, sulfur and silicon.There is some data to suggest that along with the metals, there is oxygen, sulfur and silicon.

Seeing the layers differently… YOU DO NOT HAVE TO WRITE THIS SLIDE. YOU DO HAVE TO USE THE WEBSITE!!! YOU DO NOT HAVE TO WRITE THIS SLIDE. YOU DO HAVE TO USE THE WEBSITE!!! Check out this site: ucture.htmlCheck out this site: ucture.html ucture.html ucture.html Explore it. Play with it. It will reinforce the notes you have taken and help you to better understand what you have read and written.Explore it. Play with it. It will reinforce the notes you have taken and help you to better understand what you have read and written.

The Core and Earth’s Magnetic Field Thought that movement of liquid of outer core created Earth’s magnetic fieldThought that movement of liquid of outer core created Earth’s magnetic field Earth acts like a giant bar magnet and has a magnetic field.Earth acts like a giant bar magnet and has a magnetic field. It affects the whole planet.It affects the whole planet. This is the reason that compasses work here on Earth (magnetic).This is the reason that compasses work here on Earth (magnetic). activities/hiking/compass1.htmhttp://adventure.howstuffworks.com/outdoor- activities/hiking/compass1.htmhttp://adventure.howstuffworks.com/outdoor- activities/hiking/compass1.htmhttp://adventure.howstuffworks.com/outdoor- activities/hiking/compass1.htm View this to BETTER understand this concept of Earth’s magnetism.View this to BETTER understand this concept of Earth’s magnetism.

Convection in the Mantle How is heat transferred?How is heat transferred? Radiation – sun transfers light and heat through the air warming the objects on Earth. Transfer of energy through waves is radiation.Radiation – sun transfers light and heat through the air warming the objects on Earth. Transfer of energy through waves is radiation. Convection – heat transferred by movement of a fluid. Happens in air and water. Hot air or water rises and cold air or water falls.Convection – heat transferred by movement of a fluid. Happens in air and water. Hot air or water rises and cold air or water falls. Conduction – heat transferred between things that are touching. (Direct contact such as your feet on the hot pavement in summertime.)Conduction – heat transferred between things that are touching. (Direct contact such as your feet on the hot pavement in summertime.)

Convection Currents As air or plain liquids get hot, they expand. This makes them less dense. ( DENSITY is how much mass there is in an a given amount of volume for a substance.) The warm, less dense soup rises, and the cooler, denser soup sinks towards the bottom. (Gravity is responsible for this sinking. Denser objects sink in less dense objects.)As air or plain liquids get hot, they expand. This makes them less dense. ( DENSITY is how much mass there is in an a given amount of volume for a substance.) The warm, less dense soup rises, and the cooler, denser soup sinks towards the bottom. (Gravity is responsible for this sinking. Denser objects sink in less dense objects.) This begins a constant flow called convection current.This begins a constant flow called convection current. A heat source is needed to keep this working.A heat source is needed to keep this working.

Convection Currents in the Mantle Large amounts of heat are transferred by convection currents within the core and mantle.Large amounts of heat are transferred by convection currents within the core and mantle. Heat from the core and mantle cause the convection currents in the mantle.Heat from the core and mantle cause the convection currents in the mantle. How does mantle rock flow?How does mantle rock flow? Very slowly from the bottom to the topVery slowly from the bottom to the top This process has been happening for more than 4 billion years!This process has been happening for more than 4 billion years!

Convection Currents in Outer Core Here, the currents cause Earth’s magnetic field.Here, the currents cause Earth’s magnetic field.