The Earth’s Physical Processes

The Earth Third planet from the Sun ◦ Only planet that can support life

Atmosphere Gases that extends 6,000 miles above the surface ◦ Allows us to breathe ◦ Composed of 78% nitrogen, 21% oxygen, and 1% other gases

Hydrosphere About 70% of the Earth’s surface is water ◦ Oceans, rivers, lakes, etc.

Biosphere All people, animals, and plants that live on the Earth’s surface

Lithosphere About 30% of the Earth’s surface is land ◦ Also includes the ocean basins

Layers of the Earth CONVECTION occurs in the mantle… heat rises causes a circular movement of semi-solid magma

Plate Tectonics…. Puzzle Pieces! The process of continental drift and magma flow that creates the Earth physical features

Pangaea to Today!!

Types of Plate Movement Convergent= converges or moves together! Divergent= diverges or moves apart! Transform= slides past each other!

Types of Plates 1.) Oceanic: heavier plates located under the ocean II.) Continental: lighter plates under the continents

Convergent Boundaries Subduction: when one plate sinks beneath another plate Accretion: when material piles up because of subduction

Plate Tectonics (cont) Subduction (Convergent Plates) ◦ One continental plate sinks when they collide ◦ mountains are formed EX: Himalaya Mountains (Two continental plates)

Plate Tectonics (cont) Subduction (or Convergent Plates) ◦ Heavier sea plates dive under lighter continental plates  Creates volcanic mountains EX: Andes Mountains(Oceanic and continental)

Plate Tectonics (cont) Accretion Another instance of continental and sea plates meeting  Creates underwater mountains, trenches, and volcanoes  Buildup can cause continents to grow

Plate Tectonics (cont) Spreading (or Divergent Plates) ◦ Sea plates pull apart creating rifts allowing magma to flow  Creates underwater volcanic mountains or ridges  Pushes continents apart

Plate tectonics Subduction and seafloor spreading cause trenches (underwater valleys/canyons) EX: Mariana Trench in Pacific Ocean

Plate Tectonics Spreading of two plates…Rift Valleys EX: Great Rift Valley in Africa

Plate Tectonics (cont) Transform: Faults (cracks in the Earth!) ◦ Occurs when plates grind past each other  As the plates slide, earthquakes acre created  Tsunamis are caused by transform movement under the ocean

Plate Tectonics EX: San Andreas Fault

Plate Tectonics EX: Japanese Tsunami

Plate Tectonics “Hot Spots”: weak plate areas where magma breaks through EX: Hawaiian Islands

Ring of Fire Area of SEISMIC (plate moving) activity around the Pacific Plate that causes volcanoes, earthquakes, and tsunamis

Forces that Affect the Earth Weathering – physical or chemical process that breaks down the earth’s surface ◦ Physical –rock breaks down but does not change what it’s made of EX: water seeps into rocks, freezes, expands, and breaks rocks ◦ Chemical – combination of elements to transform or breakdown minerals EX: water and CO2 combine to dissolve limestone creating caves

Forces (cont) Erosion – process of carrying rock away ◦ Wind – movement of dust, sand, and soil from one place to another Effect: moves soil from dry or deforested areas AND moves it somewhere else… Making it rich! EX: Dust Bowl in 1930s Great Plains

Erosion Contd… ◦ Glacial – large bodies of ice slowly move across the Earth’s surface EFFECT: Carves valleys in mountains AND/OR creates dams and glacial lakes EX: Rocky Mountain glacial valleys ◦ Water – fast moving rain, rivers, streams, and oceans wears away the surface Effect: gullies, valleys, canyons EX: Grand Canyon

Forces (cont) Soil Building – layers of different types of rock and soil that build up over the years WHY? rocks break down due to weathering mix with decaying plants and animals to create soil ◦ Different regions have different types  Desert sands will not support life  Grasslands are among the best