Changes Within the Earth

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Changes Within the Earth. Chapter 1 Section 2. GEOGRAPHY – the study of the earth’s physical structure and history Physical Characteristics The Earth’s Layers Core – center (inner/outer) Mantle – mostly solid Crust – rocky surface layer - PowerPoint PPT Presentation

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Changes Within the Earth

Changes Within the EarthChapter 1Section 2GEOGRAPHY the study of the earths physical structure and historyPhysical CharacteristicsThe Earths LayersCore center (inner/outer)Mantle mostly solidCrust rocky surface layer

Natural forces interact with the earths crust, creating landforms, or natural features, found on the earths surface

Land, Air, and WaterGeographers often talk of the different elements of the earths natural environment as a set of related spheres dominated by different physical formsLithosphere layer of soil, land, rock, landformsAtmosphere layer of air, water, and other substances above the surfaceHydrosphere consists of water, oceans, lakes and riversBiosphere the world of plants, animals, and other living things that occupy the land and water

70% waterContinents large landmasses in the oceans

Landforms are commonly classified according to differences in relief the difference in elevations between the highest and lowest pointsMajor landforms mountains, hills, plateaus, and plains

Physical Processes What forces shaped the landforms here?1st internal forces that originated in the earths interiorVolcanism

Form when magma breaks through the earths crust

On the surface, molten rock is called lava

Movement in the CrustBending and buckling breaks the earths crustResults in a foldHardness of rock and strength of movement determines whether a fault or fold

Understanding the PastPlate Tectonics theory states the earths outer shell is not one solid sheet of rock

Continental DriftContinental drift theory Pangaea One large continent that broke apart

Seafloor SpreadingUsing sonar, scientists began to map the floor of the Atlantic Ocean, discovering that it was not flatYoungest rock was found nearest underwater ridge system

Plate Movement/MeetingConvection - a circular movement caused when a material is heated, expands and rises, then cools and fallsSubduction when a denser plate slides beneath the other, an arc of volcanic islands may form along the plate boundaryWhen two oceanic plates collide, neither slidesBuckling, bending, foldingExpanding VolcanoesRing of Fire circle of volcanoes surrounding the Pacific Ocean

Changes on the Earths SurfaceChapter 1Section 3Weathering- the breakdown of rock at or near the earths surface into smaller pieces

Physical/Mechanical Weathering when rock is actually broken or weakened physicallyFreezing waterFrost wedgingSeeds taking root in cracks of rock

Chemical Weathering altering a rocks chemical makeup by changing the minerals that form the rock or combining them with new chemical elementsWater and carbon dioxideMoistureAcid Rain chemicals in polluted air combine with water vapor and fall back to earth

Erosion- movement of weathered material such as gravel, soil, and sandWater largest canyons and deepest valleys created by moving waterSediment small particles of soil, sand, and gravelWind 2nd major causeLoess windblown deposits of mineral-rich dust and siltSandstorms Glaciers- huge, slow-moving sheets of iceMoraines ridge like piles of rocks and debris