Landforms, Water, and Natural Resources

Forces below Earth’s Surface Plate Tectonics: explains how forces within the planet create landforms Continental Drift: Plates moves along the upper mantle at a rate of an inch per year 200 million years ago a supercontinent existed called Pangaea Theory helps geographers understand the origins of mountains and the landforms of oceans

Forces below cont. Three types of plate movement Spread Plates Collide Rift valleys form when the crust stretches Abyssal Plains, the world’s flattest and smoothest regions Continental Shelves, the continental surface extending under the shallow ocean water Plates Collide folds and faults Plates move laterally

Forces on Earth’s Surface Weathering : slow break up of rock into sediment Erosion: movement of surface material from one location to another Water, Waves, and Wind Water is most essential to erosion Wind and waves carry sediment Dust from Sahara to Caribbean Power of Ice Thick masses called glaciers move and create valleys

Shapes of Land To better understand landforms, geographers divide them into three groups Tectonic Process: Mountains, and some valleys created by volcanoes, faults and folding. Sediment: formed by sediment deposited by ice, water, or wind. Erosion: made of rock and has a thin layer of sediment. The hard rock underneath will remain. A Plateau is an example of this landform. Plateau is an elevated flatland that raises sharply above nearby land on at least one side.

Shapes of Land The terrain in most regions is a jigsaw puzzle of many landforms

The Hydrosphere 97% of Earth’s water is in the oceans Desalinization - remove salt Most of the remaining 3% is frozen in ice caps Water is always changing from gas to liquid, this movement through the hydrosphere is called the hydrologic cycle Solar energy, winds, and gravity drive this cycle

Hydrosphere Surface Water Wetlands – any landscape that is covered in water part of the year Okavango in Africa, Florida Estuaries – forms where a river meets and inlet of the sea Good harbors (NY, Seattle) Lakes formed by glaciers or continental rifts Lakes help control temps Provide water supplies, food Headwaters run into tributaries that run into rivers (watersheds or drainage basins) Ohio, Missouri, Arkansas Rivers are tributaries into the Mississippi watershed

Some lakes are not connected to an ocean Some lakes are not connected to an ocean. Lakes like the Great Salt Lake, may collect minerals from runoff. As more and more minerals build up the lake becomes salty.

Hydrosphere Groundwater When rainwater sinks into the ground, it is first stored in the soil It slowly moves down through the cracks and spaces of rock. The level at which the rock is filled is known as the water table. Can be brought to surface by pumping – too much can be bad for surface

Natural Resources Soils Renewable resource Natural material that includes both rocky sediments and organic matter Has many layers, that develop over long periods of time Leaching = downward movement of minerals and humus in soils More rain means leaching down and deep soils. Low fertility soil rainforests

Sustaining Soil Resources Producing the world’s food depends on soil Farming increases soil erosion Contour plowing helps control erosion Soil exhaustion – planting same crops over and over Soil becomes useless Crop rotation and fertilizers Dust Bowl Using dry lands Irrigation – artificially supplying water to an area Leads to soil salinization

Natural Resources Forests Deforestation Reforestation Protect soils from erosion Offer habitat for wildlife Yield useful products Deforestation Major problem in many parts of the world Clearing for farmland, fuel source, wood Haiti 2% forest left Reforestation Way to replenish forest Deforestation in Brazil

Natural Resources Air Water Essential to life Pollution threatens many parts of the world Acid rain is caused when certain pollutants mix with water vapor Global warming a concern Water Maintaining clean water is a challenge for many parts of the world Transportation systems help – canals, dams, and aqueducts (artificial channels for transporting water) Wells are most dependable source of water Drilled to depth of rock layers where groundwater is plentiful – aquifers Fossil waters are being depleted at high rates and not replenished with rain

With the increased use of coal as an energy source, China has had significant increases in air pollution. The pollution from China makes its way all around the world.

Natural Resources Mineral Resources Energy Resources Many different types and uses Ore – the mineral bearing rock Some more rare than others Energy Resources Fossil fuels – coal, natural gas and petroleum Non-renewable Uranium – nuclear power Environmental impact is significant

Renewable Energy Hydroelectric Power Geothermal Power Wind Electricity produced by moving water Geothermal Power Heat of Earth’s interior can also generate electricity Wind Solar Energy