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Geology and Nonrenewable Minerals Geology Geology – science devoted to study of dynamic processes occurring on earth's surface and interior Three major concentric zones Earth's Dynamics Core – earth's inner most zone Mantle – surrounds the core, thick zone of solid rock Asthenosphere – located right above mantle, partly melted rock Crust – continental / oceanic crust, thinnest zone of earth Lithosphere – outermost part of mantle Earth's Movement Convection cells – move large volumes of rock and heat in loops within the mantle Continent formation Tectonic Plates – move extremely slowly atop the asthenosphere Plate Boundaries Plate Movement Speed of plates – rate at which fingernails grow Seperate – Collide – Slide Past Mountain formation, earthquakes, volcanoes Seperation Magma (molten rock) flows up through resulting cracks Creates Ocean Ridges, high peeks and deep canyons Collision Continental plate rides up over the denser oceanic plate Subduction – the denser plate gets pushed down into the mantle Subduction Zone Continental plate collision causes mountain ranges to be created Slide and Grind Plates can also grind past one another Usually occurs at transform faults Most of these are located on ocean floor, but few are found on land i.e. North American Plate and Pacific Plate slide past each other near the San Andreas Fault Volcanos Volcano – occurs where magma reaches the earth's surface through a central vent / long crack Fissure Occurs near tectonic plate movement Lava – magma which reaches the earth's surface Volcanic activity can release : lava rock, hot ash, liquid lava and gases Provide some benefits : formation of mountains, soil fertilization Earthquakes Transform fault – fracture in earth's crust Seismic Waves – energy accumulate is released in form of vibrations Most earthquakes occur at boundaries of tectonic plates Scientists measure the the magnitude of seismic waves Magnitude – measure of ground motion caused by earthquake as indicated by the amplitude Measuring Earthquakes Seismograph – measures the amplitude of an earthquake Richter Scale – each unit has an amplitude of 10 times greater than the next smaller unit i.e. 5.0 is 10 times more ground shaking than 4.0 Largest earthquake : Chile, May 22, 1960 measured 9.5 on Richter Scale Tsunami Tsunami – a series of large waves generated when part of the ocean floor suddenly rises or drops Usually result of an underwater earthquake or volcanic eruption Travel across the ocean at the speed of a jet plane Waves are far apart, crests not very high at first, yet when approaching coast it slows and waves squeeze together Tsunami Detection Can be detected through network or ocean buoys or pressure recorders located on ocean floor Between 1900 and 2008, tsunamis killed an estimated 278,000 people in regions of Pacific Ocean Earth's Crust • Minerals: an solid element that has a regular internal crystalline structure. • Rocks: solid combinations of minerals. Rock Types • Sedimentary: Dead plant and animal remains • Igneous: Cooled and pressurized magma • Metamorphic: Rocks that are subject to high temperature and pressures Rock Recycling • Changes rocks from one type to another • Concentrates the planet's non renewable recousrces Mineral Resources • Fossil Fuels • Metallic Minerals • Known collectively as "nonrenewable resources" Ore • Low-grade: Small Concentration • High-grade: High Concentration Mining Types • Surface Mining oOpen Pit Mining oStrip Mining oMountaintop Removal Mining • Subsurface Mining Harmful Affects of Mining • Scarring and Disruption to Surface • Chemical Spillage • Prohibits Vegetation • Subsidence (collapse of land) Removing Metals from Ore • Smelting:Heating Ore to extract desired metals • Pollution • Ore Mineral • "Gangue" 12-4 Nonrenewable Resources The earths crusts contains many important resources that cannot be replenished Some of these resources are very common like iron while others like platinum are very scarce Five countries, the United States, Russia, Canada, South Africa, and Australia supply most of the earths nonrenewable resources United States Nonrenewable Resource Use Between the years of 1900 and 1950 the United States greatly increased its resource use. This lead to the depletion of its large supplies of resources like lead, iron, and aluminum Due to the shortage of resources, the United States import over 50% of its nonrenewable resources Important Resources Minerals are very important to a countries economic status, for instance South Africa bases its economy off the mining of Gold, Chromium, and Platinum Experts believe that four metal resources are very important to a countries economic and military strength: Manganese, Cobalt, Chromium, and Platinum Overuse of Nonrenewable Resources Thomas Graedel at Yale University did a study that stated that if every country in the world used nonrenewable resources like developed countries, than there would not be enough metal resources meet the demand of the people. Economic Depletion of Resources If we use a resource so much, until the point that its price drops lower than the cost of actually extracting and transporting the resource, than the resource will be economically depleted. Dealing With Economic Depletion When a resource becomes economically depleted than there are five ways to increase the price of the product 1. Recycle or reuse existing supplies 2. Waste less 3. Use less 4. Find a substitute 5. Or do without the resource The Cost of A Resource The cost of a resource is based off of the supply and demand of the product. In general, in a competitive market, if the supply is greater than the demand, than the market will be considered cheap On the other hand if the supply is less than the demand than the good will be considered scarce and thus will be more expensive Most mineral prices are kept artificially low to help promote economic growth Lower Grade Mining One of the ways to limit the loss of nonrenewable metals is to have lower grade mining ores, which are ores that produce less in order to increase the cost of the metal There are limiting factors however like water shortages, increased cost, and increased environmental disruption Ocean Minerals Most minerals in the ocean are not concentrated enough to be industrialized. Only Bromine, Magnesium, and Sodium Chloride are found in high enough concentrations Hydrothermal deposits may in the future become a good source of minerals from the ocean but it is currently to expensive Case Study- The U.S. General Mining Law of 1872 The law stated that a person or corporation that claims that a piece of land contains valuable minerals can assume legal ownership of the land. You must spend $500 on improvements and $120 a year for every 20 acres This applied for all lands that were not National Parks or Wilderness Areas Case Study- Cont. The impacts of this law was that people abused the law and began to build essentially whatever they wanted on the land. Also because of this law, mining companies have to pay very small taxes, around2.3% of their royalties The law has been tightened up over the last couple of decades 12-5 How Can we Use Mineral Resource More Sustainably Many scientists believe that in the future many key minerals will be able to be replaced by technology in the future Still some minerals like Platinum will probably never be replaced. Because of this we need to limit the overuse of scarce resources Recycling and Reusing The easiest way to not lose scarce resources is to recycle and reuse Recycling has a much lower environmental cost than mining. For example recycling cans and scrap aluminum has 95% less air pollution, 97% less water pollution, and uses 95% less energy Case Study-Copying Ecosystems One way to increase sustainability is to recycle and reuse minerals and chemicals similar to what is found in nature. In nature the outputs of one organism become the inputs of another This biomimicry is being tried in Kalundborg, Denmark.