Unit 7 Test

What happens when water is pumped out of aquifers faster than it can be replenished? How can this affect farmers?

As the water in aquifers is removed faster than it is renewed, water tables fall. Then farmers drill deeper wells, buy larger pumps, and use more energy to pump water to the surface, eventually depleting aquifers or making it too costly to pump the remaining water. India, China, and the U.S. are examples: the 3 largest grain producers and are overpumping aquifers for the irrigation of crops which is a positive feedback loop that ultimately leads to air pollution.

Crystalline

Crystalline means made of crystals-usually crystalline rocks look shiny in the light.

What is saltwater intrusion?

Groundwater overdrafts near coastal areas, where many of the world's largest cities and industrial areas are found, can cause contamination of groundwater supplies by pulling saltwater into freshwater aquifers thus making the groundwater undrinkable and unusable for irrigation. This problem is especially serious in coastal areas of the U.S. states of Florida, California, South Carolina, Georgia, New Jersey, and Texas, as well as in coastal areas of Turkey, Manila in the Philippines, and Bangkok in Thailand. Rising sea levels from global warming will increase saltwater intrusion and decrease the amount of groundwater available in heavily populated coastal areas. Once contamination occurs - it is hard to reverse.

smelting

Heating ores to release metals. Without effective pollution control equipment, smelters emit enormous quantities of air pollutants, including sulfur dioxide and suspend particles, which damage vegetation and acidify soils in the surrounding area. They can also cause water pollution and produce liquid and solid hazardous waste that requires safe disposal.

Why do earthquakes mostly occur at plate boundaries?

Most earthquakes happen at or near the boundaries between Earth's tectonic plates because that's where there is usually a large concentration of faults. Lithospheric plates move as coherent units relative to all other plates. Although the interiors of plates may experience some deformation, all major interactions among individual plates (and therefore most deformation) occur along their boundaries. In fact, plate boundaries were first established by plotting the locations of earthquakes. Tectonic stress can cause the plates to get "stuck" on each other. When the tension is finally released, there is an earthquake. When plates scrape against each other, they create earthquakes.

Silicate

To determine if a rock is carbonate or not, put a few drops of acid on the rock. If it effervesces, that indicates a reaction of the acid with the carbonate minerals. If it does not fizz, then it is probably a silicate.

Carbonate

To determine if a rock is carbonate or not, put a few drops of acid on the rock. If it effervesces, that indicates a reaction of the acid with the carbonate minerals. There are several different types of carbonate rock: limestone is a sedimentary rock that is usually grey in color. It is shown in the top photo to the right. When it undergoes high temperatures it becomes marble (a metamorphic rock). Marble is the white rock shown to the right.

mine tailings

Unused materials. Usually left behind at streams but removed from forests. When ore deposits that contains metals such as gold are dredged from streams, the unused materials or tailings are usually left on the land.

What are the major causes of water waste? How can these be improved (p333-334)

Wasted through evaporation, leaks, and other losses. According to water resource experts, the main cause of water waste is its low cost to users. Underpricing is mostly the result of government subsidies that provide irrigation water, electricity, and diesel fuel used by farmers to pump water from rivers and aquifers at below-market prices. Because these subsidies keep water prices low, users have little or no financial incentive to invest in water-saving technologies. According to water resource expert Sandra Postel, "By heavily subsidizing water, governments give out the false message that it is abundant and can afford to be wasted—even as rivers are drying up, aquifers are being depleted, fisheries are collapsing, and species are going extinct." But farmers, industries, and others benefiting from government water subsidies argue that the subsidies promote settlement and farming of arid, unproductive land; stimulate local economies; and help keep the prices of food, manufactured goods, and electricity low. Most water resource experts believe that when water scarcity afflicts many areas in this century, governments will have to make the unpopular decision to raise water prices. China did so in 2002 because it faced water shortages in most of its major cities, with rivers running dry, lakes disappearing, and water tables falling in key agricultural areas. Higher water prices encourage water conservation but make it difficult for low-income farmers and city dwellers to buy enough water to meet their needs. When South Africa raised water prices, it dealt with this problem by establishing lifeline rates that give each household a set amount of free or low-priced water to meet basic needs. When users exceed this amount, they pay higher prices as their water use increases—a user-pays approach. The second major cause of water waste is a lack of government subsidies for improving the efficiency of water use. A basic rule of economics is that you get more of what you reward. Withdrawing subsidies that encourage water waste and providing subsidies for efficient water use would sharply reduce water waste and help reduce water shortages. Two goals of such subsidies should be to greatly improve the efficiency of irrigation, which accounts for 70% of the world's water use, and to use inexpensive means to collect rainwater and pipe it to where it is needed.

Know how water is an economic, women's and national security issue

Water is an economic issue because it is vital for reducing poverty and producing food and energy. It is a women's and children's issue in developing countries because poor women and girls often are responsible for finding and carrying daily supplies of water. And water is a national and global security issue because of increasing tensions within and between nations over access to limited but shared water resources in the Middle East and other areas of the world.

Know how the increased use of biofuels in cars contributes to water shortages

Adding to the intensity of this global competition for water and grain is the growing use of crops such as soybeans, sugarcane, oil palms, and corn to produce biofuels. A 2007 National Academy of Science study warned that increased corn production in the United States to produce ethanol will decrease water supplies and encourage aquifer depletion in some areas and increase pollution of streams and aquifers from use of pesticides and fertilizers.

For each type of plate boundary know: Which have mountains (and why)

-Divergent boundaries: No mountains -Convergent boundaries: Yes mountains. In continental-continental convergence, continued subduction eventually brings the two continental blocks together. Whereas oceanic lithosphere is relatively dense and sinks into the asthenosphere, continental lithosphere is buoyant, which prevents it from being subducted to any great depth. The result is a collision between two continental fragments. -Transform fault boundaries: No mountains

For each type of plate boundary know: Which have subduction zones & trenches (and why)

-Divergent boundaries: No subduction zones and trenches. -Convergent boundaries: Yes subduction zones and trenches because, in convergent boundaries, two plates move toward each other and the motions is accommodated by one plate sliding beneath the other. The surface expression produced by the descending plate is a deep-ocean trench. Also called subduction zones because they are sites where lithosphere is descending (being subducted) into the asthenosphere. Subduction occurs because the density of the descending lithospheric plate is, after aging and, thus, cooling, greater than that of the underlying asthenosphere. -Transform fault boundaries: No subduction zones and trenches.

For each type of plate boundary know: Which have ridges (and why)

-Divergent boundaries: Yes ridges. Seafloor is elevated. The primary reason for the elevated position of the oceanic ridge is that newly created oceanic ridge is hot, and occupies more volume, which makes it less dense than cooler rocks. As new lithosphere is formed along the oceanic ridge, it is slowly yet continually displaced away from the zone of upwelling along the ridge axis. Thus, it begins to cool and contract, thereby increasing in density. This thermal contraction accounts for the greater ocean depths that exist away form the ridge crest. -Convergent boundaries: No ridges -Transform fault boundaries: No ridges

For each type of plate boundary know: Which have volcanoes (and why)

-Divergent boundaries: Yes volcanoes. Continental rifting is thought to occur where tensional forces stretch and thin the curst. As a result, molten rock ascends from the asthenosphere and initiates volcanic activity at the surface. -Convergent boundaries: Yes volcanoes. The subduction of oceanic lithosphere created continental volcanic arcs. When two oceanic slabs converge, one descends beneath the other, initiating volcanic activity by the same mechanism that operates at oceanic-continental plate boundaries. Water "squeezed" from the subducting slab of oceanic lithosphere triggers melting in the hot wedge of mantle rock that lies above. In this setting, volcanoes grow up from the ocean floor but can also grow upon a continental platform in an ocean-continental convergence. When subduction is sustained, it will eventually build a chain of volcanic structures that emerge as islands. The volcanic islands are spaced about 80 kilometers apart and are built upon submerged ridges of volcanic material a few hundred kilometers wide. This newly formed land consisting of an arc-shaped chain of small volcanic islands is called a volcanic island arc, or simply an island arc. Most volcanic island arcs are located in the western Pacific. At these sites the subducting Pacific crust is relatively old and dense and therefore will readily sink into the mantle. This accounts for the steep angle of descent common in the trenches of this region. Old island arcs are more complex and thicker. -Transform fault boundaries: No volcanoes

For each type of plate boundary know: The direction the plates are moving relative to each other

-Divergent boundaries: two plates move apart -Convergent boundaries: two plates move together -Transform fault boundaries: two plates grind past each other

What evidence do we have that the continents were once connected?

Alfred Wegener noticed that there was matching plant and animal fossils, coal deposits, and mountain chains on multiple continents.

What is a hot spot? How did a hot spot form the Hawaiian islands?

A hot spot is a region deep within the Earth's mantle from which heat rises through the process of convection. This heat facilitates the melting of rock. The melted rock, known as magma, often pushes through cracks in the crust to form volcanoes. In Hawaii, superheated material is too hot to sink back into the mantle and it has a fixed location within the mantle; whereas, lithosphere moves and creates a series of volcanoes with one being active at a time. Island arc is formed. One reason that Kauai is smaller than other Hawaiian islands is that it shrunk due to erosion. Can change course. Volcanoes that do not occur at plate boundaries. Earthquakes regularly happen. Can be continental and coincide with plate boundaries. https://www.youtube.com/watch?v=AhSaE0omw9o

drought

A prolonged period in which precipitation is at least 70% lower and evaporation is higher than normal in an area that is normally not dry.

grey water

About 50-75% of the slightly dirtied water from bathtubs, showers, sinks, dishwashers, and clothes washers in a typical house could be stored in a holding tank and then reused as gray water to irrigate lawns and nonedible plants, to flush toilets, and to wash cars. Israel reuses 70% of its wastewater (sewage water) to irrigate nonfood crops. In Singapore, all sewage water is treated at reclamation plants for reuse by industry. Such measures mimic the way nature purifies water by recycling it, and thus they follow one of the four scientific principles of sustainability.

Know some strategies to prevent/control groundwater depletion

Also agricultural recharge.

Other than changing irrigation methods what are some other ways to reduce water waste in agriculture? (see Israel example & Ch 12)

By 2008, watershort Israel was getting almost half of its water from desalination. Since 1950, Israel has used many of these techniques to slash irrigation water waste by 84% while irrigating 44% more land. Israel now treats and reuses 30% of its municipal sewage water for crop production and plans to increase this to 80% by 2025. The government also gradually eliminated most water subsidies to raise Israel's price of irrigation water to one of the highest in the world. Israelis also import most of their wheat and meat and concentrate on growing fruits, vegetables, and flowers that need less water. For decades, wastewater from sewage treatment plants in many parts of the world has been used to water parks and golf courses and to irrigate flowers and other nonfood crops. Israel reuses 70% of its wastewater (sewage water) to irrigate nonfood crops. Israel has become the world's most waterefficient nation and has led the world in developing technologies and a water pricing system that help the country to use its limited water supplies more sustainably. Other water-short nations would benefit from following its example in saving water.

How can an increase in the price of a mineral lead to increased supply?

Can encourage exploration for new deposits, stimulate development of better mining technology, and make it profitable to mine lower-grade ores. Can also encourage search for substitutes and promote resource conservation.

How is weathering important to the long-term carbon cycle? (How do some rocks act as a carbon sink?)

Carbon dioxide in the atmosphere naturally combines with water to form carbonic acid (and gives ordinary rain water a pH of 5-5.5). This carbonic acid will chemically weather silicate rocks when they are exposed to the atmosphere. The products of the reaction are soluble in water and will eventually travel via groundwater and surface water to the oceans. In seawater, organisms can catalyze the reactions below to form shells/skeletons out of either calcite (CaCO3) or silica (SiO2). When these shells/skeletons settle to the sea floor they can form chemical sedimentary rocks. Net loss of CO2. When more weathering occurs, more CO2 is removed from the atmosphere. -Refer to specific reactions on copy of rock cycle and carbon cycle review student template

Know where the Three Gorges Dam is and some problems associated with it.

China's Three Gorges Dam, built across the Yangtze River, is the world's largest hydroelectric dam and reservoir. This enormous reservoir will flood one of China's most beautiful areas, including 1,350 cities and villages and thousands of archeological and cultural sites. It will displace about 5.4 million people. Some scientists contend that the slower flow of water in the reservoir will continually release huge amounts of sediment that will shorten the projected life of the reservoir and limit the flood-prevention capacity of the dam. In addition, productive farming regions below the dam will no longer receive annual deposits of nutrient-rich sediment. Because the dam is built over a seismic fault, some geologists worry that it might collapse and cause a major flood that would kill millions of people. Engineers claim that the dam can withstand the maximum projected earthquake. Yet, some 80 small cracks have already been discovered in the dam. Another problem is that plant and animal matter rotting underwater in the gigantic reservoir will release methane gas—which is a much more potent greenhouse gas than CO2—into the atmosphere. The hydroelectric power generated by the dam will allow the Chinese to avoid some additional CO2 emissions by not having to build as many new coal-burning power plants. But the reservoir's methane emissions will offset these savings in CO2 emissions. Opponents of the dam also claim that it will convert the Yangtze River to the world's largest sewer, because most cities and factories along the river dump their untreated sewage and other wastes directly into it. Opponents estimate that the hidden long-term harmful environmental and social costs of the dam project will be close to $75 billion—three times the direct cost of the project. Critics claim that it would have been cheaper, less disruptive, and safer to build a series of smaller dams.

Clastic

Clastic means made of pieces of other rocks. Sometimes they are tiny (sand or mud particles) so look carefully. A clastic texture often makes rocks feel rough to the touch. If a rock is clastic, you know it is sedimentary.

How are continental & oceanic crust different in terms of density and thickness?

Continental lithosphere is much thicker than oceanic lithosphere, but it is also less dense. You could compare the continental lithosphere to a marshmallow and the oceanic lithosphere to a cracker.

be able to describe and explain environmental disadvantages of each mining method: Subsurface mining

Deep deposits are removed by subsurface mining. Subsurface mining is used to remove coal and metal ores that are too deep to be extracted by surface mining. Miners dig a deep vertical shaft, blast open subsurface tunnels and chambers to reach the deposit, and use machinery to remove the ore or coal and transport it to the surface. Subsurface mining disturbs less than one-tenth as much land as surface mining disturbs, and it usually produces less waste material. However, it leaves much of the resource in the ground and is more dangerous and expensive than surface mining is. Hazards include cave-ins, explosions, fires, and diseases such as black lung, caused by prolonged inhalation of mining dust. Another problem is subsidence—the collapse of land above some underground mines. It can tilt and damage houses, crack sewer lines, break gas mains, and disrupt groundwater systems. Mining operations also produce large amounts of solid waste—three-fourths of all U.S. solid waste. One example is the huge amounts of solid waste produced from mining gold. Finally, mining causes major pollution of water and air. This is because wind and water erosion cause toxin-laced mining wastes to be deposited in areas other than the mining site. For example, acid mine drainage occurs when rainwater seeping through a mine or mine waste pile carries sulfuric acid (H2SO4, produced when aerobic bacteria act on iron sulfide minerals in spoils) to nearby streams and ground water. In addition, huge amounts of water used to process ore often contain pollutants such as sulfuric acid, mercury, and arsenic. This contaminates water supplies and fish used for food, and it can destroy some forms of aquatic life. According to the EPA, mining has polluted about 40% of western watersheds in the United States. Mining operations also emit toxic chemicals into the atmosphere. In the United States, the mining industry produces more toxic emissions than any other industry—typically accounting for almost half of such emissions.

Know what desalination is and what problems are associated with it

Desalination involves removing dissolved salts from ocean water or from brackish (slightly salty) water in aquifers or lakes for domestic use. It is another way to increase supplies of freshwater. One method for desalinating water is distillation— heating saltwater until it evaporates (leaving behind salts in solid form) and condenses as freshwater. Another method is reverse osmosis (or microfiltration), which uses high pressure to force saltwater through a membrane filter with pores small enough to remove the salt. According to a 2004 report by the U.S. National Academy of Sciences, about 15,000 desalination plants operate in more than 125 countries, especially in the arid nations of the Middle East, North Africa, the Caribbean, and the Mediterranean. They meet less than 0.3% of the world's demand for freshwater. Saudi Arabia has the world's largest number of desalination plants, and the United States has the world's second-largest desalination capacity. By 2008, watershort Israel was getting almost half of its water from desalination. And China plans to build enough desalination plants to provide 16-25% of the water used in its coastal areas by 2010. There are three major problems with the widespread use of desalination. One is the high cost and energy footprint. It takes a lot of energy to desalinate water, with distillation requiring about ten times as much energy as reverse osmosis requires. A second problem is that pumping large volumes of seawater through pipes and using chemicals to sterilize the water and keep down algal growth kills many marine organisms. A third problem is that desalination produces large quantities of briny wastewater that contain lots of salt and other minerals. Dumping this concentrated brine into nearby coastal ocean waters increases the salinity of the ocean water, which threatens food resources and aquatic life in the vicinity. Disposing of it on land could contaminate groundwater and surface water. Using desalinated water produced by reverse osmosis to irrigate crops could reduce soil salinization. However, Israeli scientist U. Yermiyahu and his colleagues reported in 2007 that desalinization removes ions such as calcium (Ca2), magnesium (Mg2), and sulfate (SO4 2) that are essential to plant growth. Thus, these ions must be added to desalinated irrigation water, which raises its already high cost, or the desalinated water must be blended with conventional irrigation water.

Drip irrigation

Drip or trickle irrigation, also called microirrigation, is the most efficient way to deliver small amounts of water precisely to crops. It consists of a network of perforated plastic tubing installed at or below the ground level. Small pinholes in the tubing deliver drops of water at a slow and steady rate, close to the roots of individual plants. Current drip irrigation systems are costly but they drastically reduce water waste; 90-95% of the water input reaches the crops, and crop yields are 20-90% more than those of conventional gravity flow systems. By using less water, they also reduce the amount of salt that irrigation water leaves in the soil. Drip irrigation is used on just over 1% of the world's irrigated crop fields and 4% of those in the United States. This percentage rises to 90% in Cyprus, 66% in Israel, and 13% in California. If water were priced closer to the value of the ecological services it provides and if government subsidies that encourage water waste were reduced or eliminated, drip irrigation would quickly be used to irrigate most of the world's crops. Good news. The capital cost of a new type of drip irrigation system developed by the nonprofit International Development Enterprises (IDE) is one-tenth as much per hectare as that of conventional drip systems. Increased use of this inexpensive system designed for poor farmers will raise crop yields in water-short areas and help to lift poor families out of poverty. According to the United Nations, reducing current global withdrawal of water for irrigation by just 10% would save enough water to grow crops and meet the estimated additional water demands of cities and industries through 2025.

What is a resource exchange web?

Industries to interact in which the wastes of one manufacturer become raw materials of another - similar to food webs in natural ecosystems, just industrial.

Know the three classes of rocks, how each generally forms, and a potential environment that each could form in

Geologists separate rocks into major classes based on how they formed. Igneous comes from the Latin for fire and refers to rocks that have cooled from molten lava or magma. Metamorphic comes from the Greek for change and refers to rocks that have been changed from one to another through intense heat and pressure. Sedimentary rocks form from sediment that has been weathered, transported and cemented together. Another way to think of the rock cycle, with plate boundaries added in. Igneous rocks are formed at locations with volcanoes. When those volcanic mountains are weathered & eroded, the sediment is transported through rivers and stream and deposited in these locations or in other bodies of water. This is where sedimentary rocks form. In subduction zones igneous and sedimentary rock can be pulled into the mantle and turned into metamorphic rock. Not all rocks in subduction zones are melted, so we can see remnants of these subduction zones when we find metamorphic rocks at the surface.

What happens when a mineral is economically depleted?

It costs more than it is worth to find, extract, transport, and process the remaining deposits. At that point, there are five choices: recycle or reuse existing supplies, waste less, use less, find a substitute, or do without.

Know which class of rock each of the following rocks belong in: Basalt

Igneous

Know which class of rock each of the following rocks belong in: Granite

Igneous

Nonfoliated

Igneous rocks never show foliations, so this is a good way to identify them. (Keep in mind that sedimentary rocks can show layers of sediments; this is different than the foliations found in metamorophic rocks.)

What are the problems with mining low-grade ores?

Increased cost of mining and processing larger volumes of ore and limited availability of freshwater needed to mine and process some of minerals-especially in arid and semiarid areas. A third limiting factor is the environmental impacts of the increased land disruption, waste material, and pollution produced during mining and processing. *A lot harder to get the actual, valuable mineral out or metal out and that means that it is usually a lower percentage of the valuable metal within the ore so you get less yield for all the work, energy, waste, and environmental degradation that goes into that and that is because there can be a lower percentage or it just takes more energy to remove the metal from that particular type of ore. The costs tend to be greater and it is usually tackled after higher grade.

Be able to explain what happens at a subduction zone in terms of density

Lithosphere is descending (being subducted) into the asthenosphere. Subduction occurs because the density of the descending lithospheric plate is greater than that of the underlying asthenosphere. In general, oceanic lithosphere is more dense than the underlying asthenosphere whereas continental lithosphere is less dense and resists subduction. As a consequence, it is always the lithosphere that is capped with oceanic crust that is subducted.

How fast do plates move?

Lithospheric plates move relative to each other at a very slow but continuous rate that averages about 5 centimeters (2 inches) per year.

Xeriscaping

Many homeowners and businesses in water-short areas are using drip irrigation and copying nature by replacing green lawns with plants that need little water. This water-thrifty landscaping, called xeriscaping (pronounced "ZEER-i-scaping"), reduces water use by 30-85% and sharply reduces needs for labor, fertilizer, and fuel. It is also an example of reconciliation ecology, so it helps preserve biodiversity, and it reduces polluted runoff, air pollution, and yard wastes.

Be able to give an example of a metallic and a nonmetallic mineral resource.

Metallic: aluminum, iron, copper Nonmetallic: sand, gravel, limestone

Know which class of rock each of the following rocks belong in: Marble

Metamorphic

Foliated

Metamorphic rocks generally (but not always) have lines where the minerals in the rocks aligned during compression. This indicates a rock was subjected to high pressures. If a rock has this texture, it can be described as foliated.

Center-pivot irrigation

More efficient and environmentally sound irrigation technology. the center-pivot, low-pressure sprinkler uses pumps to spray water on a crop. This results in a series of circular irrigated areas as shown by the green dots in. Typically, it allows 80% of the water to reach crops. Low energy, precision application (LEPA) sprinklers, another form of center-pivot irrigation, put 90-95% of the water where crops need it.

Why don't consumers see the real cost of goods made from mineral resources?

Most consumers are unaware that the real costs of consumer products made from mineral resources are higher than their market prices, because consumers are also paying taxes to provide government subsidies and tax breaks for mining companies and to help control the harmful environmental effects of mineral extraction, processing, and use. If these hidden extra costs were included in the market prices of such goods, the harmful environmental effects of mineral extraction and processing would be sharply reduced. Recycling and reuse would increase dramatically, and many of these minerals would be replaced with less environmentally harmful substitutes.

What is acid mine drainage? What are its effects?

Occurs when rainwater seeping through a mine or mine waste pile carries sulfuric acid (H2SO4 produced when aerobic bacteria act on iron sulfide minerals in spoils) to nearby streams and groundwater. Can occur any time there are minerals with sulfur in a mine or in mine tailings. Salmon Creek Lab Notes: -The pyrite (FeS2) in the Salmon Creek Mine is the source of the iron (Fe) and sulfate (SO42- ) downstream. -When the sulfide from pyrite dissolves in water (most likely from rain), it becomes sulfuric acid, reducing the pH. This acidic water can leach (dissolve or weather) metals from the surrounding soil and rock into the stream. -TDS (Total Dissolved Solids) measures any solid materials that are dissolved in the water. The metal ions can dissolve in water and account for some of the solids that are measured as TDS. Therefore, when there are more metal ions dissolved, there is a higher TDS. -As you move downstream from the mine and the pH increases, the metals will no longer be soluble in the water. They will form precipitates on the rocks and streambed. Iron (Fe) will precipitate first, followed by aluminum (Al) and then copper (Cu). -Biological effects: Low pH is harmful to aquatic organisms; Precipitates on rocks prevent the growth of algae (the base of the food chain) and destroy habit/ nesting grounds on stream bottoms; Dissolved metals can be toxic to aquatic organisms in large quantities.

acid mine drainage

Occurs when rainwater seeping through a mine or mine waste pile carries sulfuric acid (H2SO4 produced when aerobic bacteria act on iron sulfide minerals in spoils) to nearby streams and groundwater. Can occur any time there are minerals with sulfur in a mine or in mine tailings. Salmon Creek Lab Notes: -The pyrite (FeS2) in the Salmon Creek Mine is the source of the iron (Fe) and sulfate (SO42- ) downstream. -When the sulfide from pyrite dissolves in water (most likely from rain), it becomes sulfuric acid, reducing the pH. This acidic water can leach (dissolve or weather) metals from the surrounding soil and rock into the stream. -TDS (Total Dissolved Solids) measures any solid materials that are dissolved in the water. The metal ions can dissolve in water and account for some of the solids that are measured as TDS. Therefore, when there are more metal ions dissolved, there is a higher TDS. -As you move downstream from the mine and the pH increases, the metals will no longer be soluble in the water. They will form precipitates on the rocks and streambed. Iron (Fe) will precipitate first, followed by aluminum (Al) and then copper (Cu). -Biological effects: Low pH is harmful to aquatic organisms; Precipitates on rocks prevent the growth of algae (the base of the food chain) and destroy habit/ nesting grounds on stream bottoms; Dissolved metals can be toxic to aquatic organisms in large quantities.

Surface water

One of our most important resources is surface water, the freshwater from precipitation and snowmelt that flows across the earth's land surface and into rivers, streams, lakes, wetlands, estuaries, and ultimately to the oceans. Surface water replenished by runoff is classified as a renewable but finite resource. The land from which surface water drains into a particular river, lake, wetland, or other body of water is called its watershed or drainage basin. There is a hydrological connection between surface water and groundwater because eventually most groundwater flows into rivers, lakes, estuaries, and wetlands. Thus, if we disrupt the hydrologic cycle by removing groundwater faster than it is replenished, nearby streams, lakes, and wetlands could dry up, resulting in degradation of aquatic biodiversity and various ecological services.

Where does LA get its water from? What have been some economic and ecological problems in this area since the water was diverted?

One of the world's largest water transfer projects is the California Water Project. It uses a maze of giant dams, pumps, and aqueducts to transport water from water-rich Northern California (Sacramento-San Joaquin Delta) to water-poor southern California's heavily populated agricultural regions and cities and the central valley because the demand for water is greatest there. This project supplies massive amounts of water to areas that, without such water transfers, would be mostly desert. For decades, northern and southern Californians have feuded over how the state's water should be allocated under this project. Southern Californians want more water from the north to grow more crops and to support Los Angeles, San Diego, and other growing urban areas. Agriculture consumes three-fourths of the water withdrawn in California, much of it used inefficiently for water-thirsty crops such as rice and alfalfa growing in desert-like conditions. Northern Californians counter that sending more water south degrades the Sacramento River, threatens fisheries, follows fields, and alters the environment of the delta, and reduces the river's power to flush pollutants out of San Francisco Bay. They also argue that much of the water sent south is wasted. They point to studies showing that making irrigation just 10% more efficient would provide enough water for domestic and industrial uses in southern California. But low water prices, mostly because of government subsidies make it uneconomical for farmers to invest in improving irrigation efficiency. According to a 2002 study by a group of scientists and engineers, projected global warming will sharply reduce water availability in California (especially southern California) and other water-short states in the western United States, even in the best-case scenario. Some analysts project that sometime during this century, many people living in arid southern California cities, as well as farmers in this area, may have to move elsewhere because of a shortage of water. Pumping more groundwater is not the answer, because groundwater is already being withdrawn faster than it is replenished in much of central and southern California. According to many analysts, it would be quicker and cheaper to reduce water waste by improving irrigation efficiency, not growing water-thirsty crops in arid areas, and raising the historically low price of water to encourage water conservation. Has also pitted local residents against governer and created lawsuits against state and federal governments by environmentalist groups. San Joaquin Valley farmers have lost a lot of water rights.

Know how humans contribute to damage from floods

One such human activity is removal of water-absorbing vegetation, especially on hillsides. Farm fields, pastures, pavement, or buildings usually replace such vegetation and absorb far less rainwater, or none at all. Removing protective mangrove forests in coastal areas can also allow for increased flooding from storms and tsunamis. Many such forests have been cleared to make way for shrimp farms. Draining and building on wetlands, which naturally absorb floodwaters, is the second major human activity that increases the severity of flooding. Some scientists argue that, in order to help prevent future devastation of the Gulf Coast, a major priority should be to restore its coastal wetlands. Another human-related factor that will increase flooding is global warming caused mostly by people burning fossil fuels and clearing forests. Reports in 2007 by the Organization for Economic Cooperation and Development (OECD) and the IPCC projected that, by the 2070s, as many as 150 million people living in many of the world's largest coastal cities—an amount equal to half of the current U.S. population—are likely to be at risk from flooding as a result of rising sea levels caused by climate change.

Define biomining and be able to explain how it reduces the environmental impact of mining

One way to improve mining technology is to use microorganisms that can extract minerals in a process called in-place, or in situ, (pronounced "in SY-too") mining. If naturally occurring bacteria cannot be found to extract a particular metal, genetic engineering techniques could be used to produce such bacteria. This biological approach, called biomining, removes desired metals from ores while leaving the surrounding environment undisturbed. It also reduces the air pollution associated with the smelting of metal ores and the water pollution associated with using hazardous chemicals such as cyanides and mercury to extract gold.

Approximately how much of earth's water is available as liquid freshwater?

Only a tiny fraction of the planet's abundant water supply—about 0.024%—is readily available to us as liquid freshwater in accessible groundwater deposits and in lakes, rivers, and streams. The rest is in the salty oceans, frozen in polar ice caps and glaciers, or deep underground and inaccessible.

Why is the Ogallala aquifer famous?

Originated from glaciers. One of the most serious overdrafts is in the lower half of the Ogallala, the world's largest known aquifer, which lies under eight Midwestern states from South Dakota to Texas (Great Planes). The gigantic Ogallala aquifer supplies about one third of all the groundwater used in the United States and has helped to turn the Great Plains into one of the world's most productive irrigated agricultural regions. The problem is that the Ogallala is essentially a one time deposit of liquid natural capital with a very slow rate of recharge. The northernmost states (Wyoming, Nebraska, South Dakota, and parts of Colorado) still have ample water supplies from the aquifer. However, in parts of the southern states, where the aquifer is thinner, the water is being depleted rapidly—especially in the Texas-Oklahoma High Plains. In some of these areas water is being pumped out at a rate that is 10-40 times higher than the natural recharge rate. This has lowered the water table more than 30 meters (100 feet). The resulting higher pumping costs make it too expensive to irrigate crops in some areas. As a result, the amount of irrigated farmland in Texas has decreased by about 11% in recent years, as farmers abandon agriculture or return to lower yield dryland farming. Government subsidies designed to increase crop production and to encourage farmers to grow water thirsty crops have only accelerated depletion of the Ogallala. They include crop-disaster payments and tax breaks in the form of groundwater depletion allowances (with larger breaks for heavier groundwater use). Depletion of the Ogallala threatens biodiversity. In some places, the Ogallala flows onto the land and creates wetlands, which are vital habitats for many species, especially birds. When the water tables fall, many of these aquatic oases of biodiversity will disappear, along with the ecosystem services they provide.

Why do humans like to live on floodplains? What ecological benefits do they provide?

People settle on floodplains because of their many advantages, including fertile soil, ample water for irrigation, availability of nearby rivers for transportation and recreation, and flat land suitable for crops, buildings, highways, and railroads.

What are percolation ponds?

Percolation ponds are water supply facilities, built strategically in areas where gravel and permeable material allow water to seep into our aquifers. Their primary and most important purpose is to allow water to filter underground.

Know the mechanism of plate tectonics

Plate tectonics is a unifying framework for understanding the dynamic geology of the Earth. The theory posits that the outermost layers of the Earth (the crust and uppermost mantle) make up the brittle lithosphere of the Earth. Continental lithosphere is much thicker than oceanic lithosphere, but it is also less dense. You could compare the continental lithosphere to a marshmallow and the oceanic lithosphere to a cracker. The lithosphere is broken up into a number of thin plates, which move on top of the asthenosphere (middle mantle). The asthenosphere is solid, but flows plastically over geologic time scales (millions of years). Plate interiors are relatively stable, and most of the tectonic action (earthquakes, volcanism) takes place where plates meet - where they collide at convergent boundaries, move away from one another at divergent boundaries, or slide past one another at transform boundaries.

Runoff

Precipitation that does not infiltrate the ground or return to the atmosphere by evaporation is called surface runoff.

Cone of depression

Pumping from a well in a water table aquifer lowers the water table near the well. This area is known as a cone of depression. The land area above a cone of depression is call the area of influence.

What can cause reserves to increase?

Reserves increase when new profitable deposits are found and when higher prices or improved mining technology make it profitable to extract.

Know which class of rock each of the following rocks belong in: Limestone

Sedimentary

Know which class of rock each of the following rocks belong in: Sandstone

Sedimentary

Know the harmful environmental effects of extreme drought. By 2059, how much of the world is likely to be in an extreme drought?

Severe drought has a number of harmful environmental effects. It dries out soils, reduces stream flows, decreases tree growth and biomass, lowers net primary productivity, reduces crop yields, and causes a shift in some biomes toward relatively dry conditions such as those found in savannas and deserts. By 2059, as much as 45% of the earth's land surface could experience extreme drought, mostly as a result of climate change caused by global warming.

How is sedimentary rock similar to soil?

Similar to soil because, in the rock cycle, sedimentary rocks can be created through weathering and erosion which is how soil is created.

What are the advantages and disadvantages of privatizing water resources

Some argue that private companies have the money and expertise to manage these resources better and more efficiently than government bureaucracies can. Experience with this public-private partnership approach has yielded mixed results. Some private water management companies have done a good job. Some government officials want to go even further and sell public water resources to private companies. Many people oppose full privatization of water resources because they believe that water is a public resource too important to be left solely in private hands. Also, once a city's water systems have been taken over by a foreign-based corporation, efforts to return the systems to public control can be quite costly for taxpayers and can lead to severe economic penalties under the rules of the World Trade Organization (WTO). Some analysts point to two other potential problems in a fully privatized water system. First, because private companies make money by delivering water, they have an incentive to sell as much water as they can rather than to conserve it. Second, because they have too little money to pay water bills, the poor will continue to be left out. There are no easy answers for managing the water that everyone needs.

be able to describe and explain environmental disadvantages of each mining method: Open-pit mining

Surface mining; Machines dig holes and remove ores (of metals such as iron, copper, and gold), sand, gravel, and stone (such as limestone and marble). Causes air pollution, evaporation, contamination from animals.

be able to describe and explain environmental disadvantages of each mining method: Strip mining

Surface mining; Strip mining is useful and economical for extracting mineral deposits that lie close to the earth's surface in large horizontal beds. In area strip mining, used where the terrain is fairly flat, gigantic earthmovers strip away the overburden, and power shovels—some as tall as a 20-story building—remove the mineral deposit. The resulting trench is filled with overburden, and a new cut is made parallel to the previous one. This process is repeated over the entire site. Contour strip mining is used mostly to mine coal on hilly or mountainous terrain. A huge power shovel cuts a series of terraces into the side of a hill. An earthmover removes the overburden, a power shovel extracts the coal, and the overburden from each new terrace is dumped onto the one below. Unless the land is restored, a wall of dirt is left in front of a highly erodible bank of soil and rock called a highwall. Leaves a series of hills like waves of rubble called spoil banks: Spoils and tailings are very susceptible to chemical weathering and erosion by water and wind. Regrowth of vegetation on these banks is quite slow because they have no topsoil and thus have to follow the long path of primary ecological succession.

be able to describe and explain environmental disadvantages of each mining method: Mountaintop removal

Surface mining; Surface mining method; In the Appalachian Mountain area of the United States, where this form of mining is prominent, explosives, large power shovels, and huge machines called draglines are used to remove the top of a mountain and expose seams of coal; which are then removed. Destroys forest, buries mountain streams, and increases flood hazards; Toxic wastewater, produced when the coal is processed, is often stored in these valleys behind coal waste sludge dams, which can overflow or collapse, releasing toxic substances such as selenium, arsenic, and mercury. Nearby communities can be damaged economically, as well as environmentally.

What is subsidence? Know how it relates to groundwater & mining.

The gradual sinking of land surface. Withdrawing large amounts of water sometimes causes the sand and rock in aquifers to collapse, which causes the land above the aquifer to subside or sink, a phenomenon known as land subsidence. Once an aquifer becomes compressed from subsidence, recharge is impossible. Land subsidence can damage roadways, water and sewer lines, and building foundations. Areas in the United States suffering from this problem include California's San Joaquin Valley, Baton Rouge in Louisiana, the Phoenix area in Arizona, and the Houston-Galveston area in Texas. Mexico City, built on an old lakebed, has one of the world's worse subsidence problems because of increasing groundwater overdrafts due to rapid population growth and urbanization. Some parts of the city have sunk as much as 10 meters (33 feet). Parts of Beijing in China and Bangkok in Thailand are also sinking. Sinkholes, which can appear suddenly and unexpectedly, are another kind of land subsidence. They are large craters that form when the roof of an underground cavern collapses after being drained of the groundwater that supports it. Sinkholes can appear suddenly and can swallow homes, businesses, roads, cars, and trees. Problem in subsurface mining; the collapse of land above some underground mines. It can tilt and damage houses, crack sewer lines, break gas mains, and disrupt groundwater systems.

Know the basic steps of the water cycle

The hydrologic cycle is also known as the water cycle. The energy of the sun drives the water cycle. This cycle provides a natural service: renewal of water quality. A major sink for water is the atmosphere, in addition to oceans and other surface water. Water comes out of the atmosphere and enters terrestrial living systems through precipitation. There is one term missing from the diagram that refers to the loss of water vapor from plants to the atmosphere, called transpiration.

Watershed

The land from which surface water drains into a particular river, lake, wetland, or other body of water is called its watershed or drainage basin.

Know the advantages and disadvantages of dams/ reservoirs

The main goals of a dam and reservoir system are to capture and store runoff and release it as needed to control floods, generate electricity (hydroelectricity), and supply water for irrigation and for towns and cities. Reservoirs also provide recreational activities such as swimming, fishing, and boating. Large dams (22,000 of them in China) have increased the annual reliable runoff available for human use by nearly one-third. As a result, reservoirs now hold 3 to 6 times more water than flows in the world's natural rivers. These dams and reservoirs have helped to reduce flooding and grow crops in arid areas. One-fourth of the world's dams produce about 20% of the world's electricity. Large dams and reservoirs also have disadvantages. Worldwide, this engineering approach to river management has displaced 40-80 million people from their homes. It has flooded an area of mostly productive land roughly equal to the area of the U.S. state of California, and it has impaired some of the important ecological services rivers provide. And according to the 2007 WWF study, about one-fifth of the world's freshwater fish and plant species are either extinct or endangered primarily because dams and water withdrawals have destroyed many free-flowing rivers. Because of evaporation and seepage into porous rock beds, the reservoirs behind some dams lose large amounts of water. Reservoirs also eventually fill up with sediment, mud, and silt, usually within 50 years, which makes them useless for storing water or producing electricity. About 85% of dam and reservoir systems in the United States will be 50 years old by 2020.

Why does melting of mantle rock occur at divergent boundaries?

The separation of plates releases pressure. At divergent plate boundaries hot mantle rock rises into the space where the plates are moving apart. As the hot mantle rock convects upward it rises higher in the mantle. The rock is under lower pressure; this lowers the melting temperature of the rock and so it melts.

Know where the Aral Sea is and why it has shrunk

The shrinking of the Aral Sea is the result of a large-scale water transfer project in an area of the former Soviet Union with the driest climate in central Asia to Kazakhstan, Uzbekistan for agriculture. Since 1960, enormous amounts of irrigation water have been diverted from the inland Aral Sea and its two feeder rivers to create one of the world's largest irrigated areas, mostly for raising cotton and rice. The irrigation canal, the world's longest, stretches more than 1,300 kilometers (800 miles). This large-scale water diversion project, coupled with droughts and high evaporation rates due to the area's hot and dry climate, has caused a regional ecological and economic disaster. Since 1961, the sea's salinity has risen sevenfold, leading to the extinction of fish, and the average level of its water has dropped by 22 meters (72 feet). It has lost 89% of its volume of water and has split into two major parts. Water withdrawal for agriculture has reduced the two rivers feeding the sea to mere trickles. This drier climate has led to dust storms which pollute and contaminate elsewhere. Climate altered and wetlands destroyed which decreases biodiversity. Economically, has collapsed the fish industry, lost tourism, lowered crop yields due to desertification - forcing more pesticides and fertilizers to be used which leads to pollution.

overburden

The soil and rock overlying a useful mineral deposit stripped away in surface mining by gigantic mechanized equitement. Usually discarded as waste material called spoils.

Zone of saturation

The spaces in soil and rock close to the earth's surface hold little moisture. Below a certain depth, in the zone of saturation, these spaces are completely filled with water.

Water table

The spaces in soil and rock close to the earth's surface hold little moisture. Below a certain depth, in the zone of saturation, these spaces are completely filled with water. The top of this groundwater zone is the water table. It falls in dry weather, or when we remove groundwater faster than nature can replenish it, and it rises in wet weather.

What is depletion time? What can influence depletion time?

The time it takes to use up a certain proportion-usually 80%-of the reserves of a mineral at a given rate of use. When experts disagree about depletion times, it is often because they are using different assumptions about supplies and rates of use. Depends on supply and rate of use. The shortest depletion time estimate assumes no recycling or reuse and no increase in reserves (curve A). A longer depletion time estimate assumes that recycling will stretch existing reserves and that better mining technology, higher prices, or new discoveries will increase reserves (curve B). An even longer depletion time assumes that new discoveries will further expand reserves and that recycling, reuse, and reduced consumption will extend supplies (curve C). Finding a substitute for a resource leads to a new set of depletion curves for the new resource. Factors that could influence depletion time of a resource are, therefore, mining, use, throwing away, no new discoveries, rising prices, recycling, increasing reserves by improved mining technology, higher prices, new discoveries, reusing, and reducing consumption.

How is surface water connected to groundwater?

There is a hydrological connection between surface water and groundwater because eventually most groundwater flows into rivers, lakes, estuaries, and wetlands. Thus, if we disrupt the hydrologic cycle by removing groundwater faster than it is replenished, nearby streams, lakes, and wetlands could dry up, resulting in degradation of aquatic biodiversity and various ecological services.

Aquifer

Underground caverns and porous layers of sand, gravel, or bedrock through which groundwater flows. Groundwater normally moves from points of high elevation and pressure to points of lower elevation and pressure. Some caverns have rivers of groundwater flowing through them. But the porous layers of sand, gravel, or bedrock in most aquifers are like large elongated sponges through which groundwater seeps—typically moving only a meter or so (about 3 feet) per year and rarely more than 0.3 meter (1 foot) per day. Watertight layers of rock or clay below such aquifers keep the water from escaping deeper into the earth. Most aquifers are replenished naturally by precipitation that percolates downward through soil and rock, a process called natural recharge. Others are recharged from the side by lateral recharge from nearby rivers and streams. Most aquifers recharge extremely slowly. Because so much of the urban landscape has been built on or paved over, water can no longer penetrate the ground to recharge aquifers in some urban areas. Nonrenewable aquifers get very little, if any, recharge. They are found deep underground and were formed tens of thousands of years ago. Withdrawing water from these aquifers amounts to mining a nonrenewable resource. Such withdrawals will deplete these ancient deposits of liquid natural capital, and they represent an unsustainable use of this resource. *Lake can tell a lot; pore space filled with air above water table and pore space filled with water below water table.

Why does melting of mantle rock occur at subduction zones?

When a descending oceanic slab reaches a depth of about 100 kilometers, melting is triggered within the wedge of hot asthenosphere that lies above it. But how does the subduction of a cool slab of oceanic lithosphere cause mantle rock to melt? The answer lies in the fact that volatiles (mainly water) act like salt does to melt ice. That is, wet rock, in a given pressure environment, melts at substantially lower temperatures than "dry" rock of the same composition. Sediments and oceanic crust contain a large amount of water which is carried to great depths by a subducting plate. As the plate plunges downward, water is "squeezed" from the pore spaces as confining pressure increases. At even greater depths, heat and pressure drive water from hydrated (water-rich) minerals such as the amphiboles. At a depth of roughly 100 kilometers and several kilometers from the upper boundary of the cool subducting oceanic slab, the mantle is sufficiently hot that the introduction of water leads to some melting. This process, called partial melting, generates as little as 10 percent molten material, which is intermixed with unmelted mantle rock. Being less dense than the surrounding mantle, this hot mobile mixture (magma) gradually rises toward the surface as a teardrop-shaped structure. Depending on the environment, these mantle-derived magmas may ascend through he crust and give rise to a volcanic eruption. However, much of this molten rock never reaches the surface; rather, it solidifies at depth where it acts to thicken the crust. Water in ocean crust lowers melting point.

Study units 1-6 study guides

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