AP Environmental Science Chapter 8

topsoil

(A horizon) Frequently the top layer of soil, characterized by mixing of organic material and mineral material. ex: see A horizon.

ore

A concentrated accumulation of minerals from which economically valuable materials can be extracted. ex: Ores are typically characterized by the presence of valuable materials, but accumulation of other valuable materials such as salt or sand can be considered an ore. Formed by a variety of geological processes. Some occur in veins- high concentration but small area and some occur in disseminated deposits= larger area of rock but less concentrated.Nonmetallic mineral resources such as clay, sand, salt, phosphate, and limestone usually occur in concentrated deposits.

fault

A fracture in rock caused by a movement of Earth's crust. ex: Although the plates are always in slow motion, their movement is not necessarily smooth.

fault zone

A large expanse of rock where a fault has occurred. ex: Form a brittle upper layer of the lithosphere where two plates meet.= rock near the plate margins becomes fractured and deformed due to the immense pressure exerted by the plate movement= the plates resist movement and get stuck as the plates attempt to move= eventually pressure overcomes the resistance and this slipping quickly= earthquake.

placer mining

A mining technique in which metals and precious stones are sought in river sediments. ex: Miners use river water to separate heavier items, such as diamonds, tantalum,and gold, from lighter items such as sand ans mud= gold rush.

mountaintop removal

A mining technique in which the entire top of a mountain is removed with explosives. ex: Large earth-moving equipment removes the resource and deposits the tailings in lower-elevation regions nearby, often into streams or rivers.

open-pit mining

A mining technique that uses a large pit or hole in the ground, visible from the surface of Earth. ex: Used when the resource is is close to the surface but extends beneath the surface both horizontally and vertically. Copper mines are usually open-pt mines.

soil

A mix of geological and organic components that forms a dynamic membrane covering much of Earth's surface. ex: Soil formation takes place at Earth's surface. Soil serves as a medium for plant growth, filters water, is a habitat for a variety or organisms (biodiversity) and breaks down organic material and cycles nutrients. Takes hundreds of thousands of years to form. Soil is the results of physical and chemical weathering of rocks and gradual accumulation of detritus from the biosphere. Can determine the specific properties of soil if we know the parent rock type, the amount of time during which it has been forming, and its associated biotic and abiotic components. Soil is formed from below (weathering) and above (breakdown of organic materials and their wastes). Immature soil= not a lot of organic material. Very old soil can be nutrient poor because plants suck up the nutrients and leaching of nutrients occurs. Most be considered together= the five properties that determine soil properties: parent material, climate, topography, organisms, and time.

Richter scale

A scale that measures the largest ground movement that occurs during an earthquake. ex: Logarithmic (increases by a factor of ten). Worldwide there may be more than 800,000 small earthquakes of magnitude 2.0 or less per year, but an earthquake of magnitude 8.0 occurs only approximately every 10 years, however, even a moderate amount of Earth movement can be devastating (5.0 to 5.9)= ex: proximity of large population to epicenter and poor construction of buildings. Extra precautions are needed when dangerous materials are used in an area of seismic activity (ex: nuclear power plants). 85 percent of active volcanoes occur along plate boundaries (and can occur over hotspots)= not distributed equally= can eject ash, dust rock and cinder into the air= can result in loss of life, habitat destruction and alteration, reduction in air quality, and many other environmental consequences (ex: 2010 volcano in Iceland).

horizons

A soils form, they develop characteristic horizons, or layers. ex:The five factors that influence soil type vary across the landscape, so they lead to the formation of different soil types in different locations.The specific composition of those horizons depends largely on climate, vegetation, and parent material.

mineral

A solid chemical substance with a uniform, often crystalline, structure that forms under specific temperatures and pressures. ex: Usually compounds but may be composed of a single element such as silver or gold.

volcano

A vent in the surface of Earth that emits ash, gases, or molten lava. ex: Earth's history is measured using the geologic time scale. Over a period of time, species that existed on a single continent evolved into two different species on two separate islands= helps scientists determine how species will adapt to the relatively rapid climate change that is happening today. As a plate moves over a geologic hotspot, heat from the rising mantle plume melts the crust, forming a volcano= natural source of atmospheric carbon dioxide, particulates, and metals= as plate moves past the hot spot it can leave behind a trail of volcanic islands, as is Hawaii's case.

divergent plate boundries

An area beneath the ocean where tectonic plates move away from each other. ex: The zones of plate contact can be classified into three types: divergent plate boundaries, convergent plate boundaries, and transform fault boundaries. At divergent plate boundaries, oceanic plates move apart as if on a giant conveyer belt= magma reaches Earth's surface and pushes upward and outward, new rock is formed<sea floor spreading.

convergent plate boundary

An area where plates move towards one another and collide. ex: If plates are diverging and Earth has a finite area= plates must be moving together somewhere= convergent plate boundaries. Plates generate a great deal of pressure as they move towards one another and collide. If the margin of oceanic plate composed of dense, iron-rich rock collides with that of a lighter continental plate, the oceanic plate margin, and the plate, will slide under the continental crust, pushing up the lighter plate= subduction of heavier plates= frormatiom of long, narrow coastal mountain ranges, such as the Andes. Because subducted plates will melt= rising magma may be the source of new volcano formation. If two continental plates meet, both plate margins may be lifted, forming a mid-continental mountain range such as the Himalayas.

transform fault boundary

An area where tectonic plates move sideways past eachother. ex: Most plates and continents move at about the rate your fingernails grow= 36 mm or 1.4 inches per year.

Metal

An element with properties that allow it to conduct electricity and heat energy, and perform other important functions. ex: ex: copper, aluminum, and nickel. In rock, they exist in various concentrations, usually in association with elements such as sulfur, oxygen, and silicon. However, some metals, such as gold, exits in natural pure form.

b horizon

Frequently the second major soil horizon, composed primarily of mineral material with very little organic material. ex: All soils have a B horizon. Commonly known as subsoil. If there are nutrients in the soil, they will be present in the B horizon.

A horizon

Frequently the top layer of soil, characterized by mixing of organic material and mineral material. ex: In soil that is mixed, either by human agricultural processes or naturally, the top layer is the a horizon. Also called topsoil.

intrusive igneous rock

Igneous rock that forms when magma rises up and cools in place underground. ex: The formation of igneous rock often brings to the surface rare elements and metals that humans find economically valuable, such as lanthanum.

fracture

In geology, a crack that occurs in a rock as it cools. ex: When rock cools it is subject to stresses that may cause t to break= cracks=fractures= can occur in any kind of rock. Water from Earth's surface running through fractures may dissolve valuable metals, which may precipitate out in the fractures to form concentrated deposits called veins= deposits important source of gold- and silver-bearing ores and tantalum (cell-phones).

hot spot

In geology, a place where molten material from Earth's mantle reaches the lithosphere. ex: Earth's geological cycle 3 major processes= tectonic cycle, rock cycle, and soil formation. Earth's formation and elemental composition consequence= it is very hot at its center. High temp. of Earth's core and mantle= radioactive decay of various isotopes of elements such as potassium, uranium, and thorium, which releases heat. The heat causes plumes of hot magma to well upward from the mantle= produce hotspots. He4at from Earth's core creates convection cells in a similar fashion to those of atmospheric circulation. Mantle convection drives the continuous change, creation, and renewal of Earth materials in the lithosphere.

crust

In geology, the chemically distinct outermost layer of the lithosphere. ex: Regions overlap: the lower part of the lithosphere is also the uppermost portion of the mantle.

core

In reference to Earth, the innermost layer. ex: Earth's mineral are unevenly distributed around the world. Elements settled into place based on their mass= the planet is characterized by distinct vertical zonation= concentric layers composed of various materials. over 3,000 km (1,860 miles) below Earth's surface. The core is a dense mass largely made up of nickel and some iron. the inner core is solid, and the outer core is liquid.

reserve

In resource management, the known quantity of a resource that can be economically recovered. ex: The global supply of mineral resources is difficult to quantify. The publicly known estimate of how much of a particular resource is available= reserve.

subsurface mining

Mining techniques used when the desired resource is more that 100m (328 feet) below the surface of Earth. ex: Typically, a subsurface mine begins with a horizontal tunnel dug into the side of a mountain or other feature containing the resource= from this vertical shafts are drilled and elevators used to bring the miners down and the resource back to the surface. ex: used for coal, diamonds, and gold.

magma

Molten rock. ex: when it cools can form rocks.

acid rains

Precipitation high in sulfuric acid and nitric acid from reactions between sulfur dioxide and water vapor and nitrogen oxides and water vapor in the atmosphere. ex: Sulfur emitted into the atmosphere as a result of fossil fuel combustion combines with oxygen to form sulfur dioxide. The sulfur dioxide reacts with water vapor in the atmosphere to form sulfuric acid= causes acid precipitation. Causes rapid degradation. When acid precipitation falls on soil, it can promote chemical weathering of certain minerals in the soil, releasing elements that may be taken up by plants or leached from the soil into groundwater systems. Can contribute to additional elements in an ecosystem= can also reduce atmospheric carbon dioxide= weathering of certain granitic rocks consume carbon dioxide.

igneous rocks

Rock formed directly from magma. ex: Classified by their chemical composition as either basaltic (dark-colored rock that contains minerals with high concentrations of iron, magnesium, and calcium= it is the dominant type of crust in oceanic plates) or granitic (lighter-colored rock made up of minerals feldspar, mica and quartz, which contains elements such as silicon aluminum, potassium, and calcium= dominant rock in the crust of continental plates= when breaks down from weathering makes sand= soils that form from this tend to be more permeable than those that develop from basaltic tock, but both types can form fertile soil), and by their mode of formation as intrusive or extrusive.

extrusive igneous rock

Rock that forms when magma cools above the surface of Earth. ex: Such as when magma is released from a volcano or sea floor spreading= cool rapidly= minerals have little time to expand into large individual crystals= just form into fine-grain smooth rock types like obsidian. Both extrusive and intrusive rock types can be either granitic or basaltic in composition. The formation of igneous rocks often brings to the surface rare elements that humans find economically valuable, such as lanthanum.

metamorphic rock

Rock that forms when sedimentary rock, igneous rock, or other metamorphic rock is subjected to high temperature and pressure. ex: Pressures can cause profound chemical and physical property changes in the rock= can be caused by overlying rock or by tectonic processes such as continental collisions, which cause extreme horizontal pressure and distortion. Include stones such as slate and marble as well as anthracite, a type of coal. Building materials for humans= structurally strong and visually attractive.

sedimentary rock

Rock that forms when sediments such as muds, sands, or gravels are compressed by overlying sediments. ex: Occurs over long periods of time when environments such as sand dunes, mudflats, lake beds, or landslide-prone areas are buried and overlying materials create pressure on the material below. The resulting rock may be uniform in composition= sandstones and musdstones that from ancient oceanic or lake environments or heterogeneous= conglomerate rocks formed from mixing cobbles, gravels, and sands. Fossils= when layers of sediment containing plant or animal remains are compressed over eons. organic material may be preserved.

parent material

Rock underlying soil; the material from which the inorganic components of a soil are derived. ex: Different soil types arise from different parent materials (can be nutrient poor or very fertile soil or in between).Climate= very cold places= poor soil because water cannot move through soil and organic material cannot decompose. topography= steep slop= erosion of soil and at the bottom soil accumulates and becomes deep. Organisms= can mix the soils if they borrow and many organisms excrete organic acids that speed chemical weathering and humans affect soil. Time= Old soils with a lot of organic material above them (grasslands)= fertile while old soils with little organic material above them or a lot of water running through them= infertile.

cation exchange capacity (CEC)

The ability of a particular soil to absorb and release cations. ex: Clay particles contribute the most to the chemical properties of soil because of their ability to attract positively charged mineral ions= cations. Because clay particles have a negative charge, cations are absorbed- held on the surface- by the particles. These cations can be subsequently released from the particles and used as nutrients by plants. CEC= nutrient holding capacity. The overall CEC of a soil is a function of the amount and types of clay particles present (too much clay= waterlogged soil though)

deposition

The accumulation of depositing or eroded material such as sediment, rock fragments, or soil. ex: Erosion is a natural process: streams, glaciers, and wind-borne sediments continually carve, grind, and scour rock surfaces. However can be human land usage contributing to erosion. Poor land use practices such as deforestation, overgrazing, unmanaged construction activity, and road building can create and accelerate erosion problems= leads to deposition of eroded materials somewhere else= problems.

crustal abundance

The average concentration of an element in Earth's crust. ex: Early Earth cooled and and differentiated into distinct vertical zones Heavy elements sunk toward the core, and lighter elements rose towards the crust. Chemical composition of the crust in one location is highly variable. Oxygen silicon, aluminum, and iron constitute over 88 percent of the crust.

chemical weathering

The breakdown of rocks and minerals by chemical reactions, the dissolving of chemical elements from rocks, or both. ex: Releases essential nutrients from the rocks. Most important on newly exposed minerals= primary minerals because it alters them to form secondary minerals and the ionic forms of constituent elements. ex= acid rains and lichens weak acid breaking down rock. Rocks that contain compounds that dissolve easily tend to weather quickly. Some chemical weathering is a result of human activities.

rock cycle

The continuous formation and destruction of rock on and below the surface of Earth. ex: The slowest of all of Earth's cycles= environmental scientists are most concerned with the part of the rock cycle that occurs at the Earth's surface. Rock= the substance of the lithosphere= composed mostly of minerals. Slo9wly forms new rocks and breaks down old rocks. Three types of rocks are created in the rock cycle: igneous rock is formed from magma; sedimentary rock is formed by the compression of sedimentary materials; and metamorphic rock is created when rocks are subjected to high temperatures and pressures. Magma= the original source of all rock. Rock forms when magma from Earth's interior reaches the surface, cools, and hardens. Once at Earth's surface, rock masses are broken up, moved, and deposited in new locations by processes such as erosion and weathering. New rock may be formed from the deposited material. Eventually, the rock is subducted into the mantle, where it melts and becomes magma again.

tectonic cycle

The cycle of processes that build up and break down the lithosphere. ex: Oceanic plates (dense and rich with iron)= under oceans; continental plates= under land masses (silicon dioxide= much less dense than iron)= Continental plates are generally lighter and rise above oceanic plates. Slow plate movements are driven by convection cells in the mantle. As oceanic plates move apart, rising magma forms new oceanic crust on the seafloor at boundaries between the plates= seafloor spreading.

epicenter

The exact point on the surface of Earth directly above the location where rock ruptures during an earthquake. ex: Earthquakes are a direct result of the movement of plates and their contact with each other. Volcanic eruptions happen when the molten magma under the crust is released to the atmosphere. Sometimes the two events are observed together , most often along plate boundaries where tectonic activity is high. (ex "Ring of Fire" where earthquake and volcanoes circle the Pacific Ocean).

seafloor spreading

The formation of new ocean crust as a result of magma pushing upward and outward from Earth's mantle to the surface. ex: Creates new lithosphere by bringing important elements such as copper, lead and silver to the surface of Earth= typically under the deep ocean but over tens to hundreds of millions of years, as the tectonic cycle continues, some of the material from new land containing these valuable resources.

seismic activity

The frequency and intensity of earthquakes. ex: Areas of seismic activity= fault zones. (Ex: San Andreas Fault in California)

Mantle

The layer of Earth above the core, containing magma. ex: Contains molten rock, or magma, that slowly circulates in convection cells, much as the atmosphere does.

asthenosphere

The layer of Earth located in the outer part of the mantel, composed of semi-molten rock. ex: Semi-molten rock= ductile (flexible) rock.

c horizon

The least weathered soil horizon, which always occurs beneath the b horizon and is similar to the parent material. ex: Each of the horizons lends certain physical, chemical, and biological properties to the soil within which it exists.

soil degradation

The loss of some or all of the soil's ability to support plant growth. ex: One of the major causes is soil erosion= when topsoil is removed. Takes centuries for lost topsoil to be replaced. Humans have major impact on this. Compaction of soil= bad because reduces its ability to retain water and thusly the amount o vegetation that grows there is decreased and thusly erosion is increased.

physical weathering

The mechanical breakdown of rocks and minerals. ex: Rock on Earth's surface breaks down due to weathering and erosion= components of the rock cycle= return chemical elements and rock fragments to the crust by depositing them as sediments via the hydrologic cycle. Begins the cycle all over again= without weathering and erosion elements would never be recycled. Physical and chemical weathering work in combination to breakdown rocks. Weathering occurs when rock is exposed to air, water, certain chemical compounds, or biological agents such as plant roots, lichens, and burrowing animals. Can be caused by water, wind or variations of temperatures such as in seasonal freeze- thaw cycles= water in fissures or cracks in rocks= remove loose materials and widen the cracks and when freezes= water expands and the pressure can cause the rock to break. Different responses to temperature can cause two minerals within a rock to expand and contract differently= splitting of rocks. Coarse grained rocks= slow cooing of metamorphism tends to weather more easily. Biological things can also cause minor weathering. Physical weathering exposes more surface area and makes rocks more vulnerable to further degradation= also increases the rate of chemical weathering.

O horizon

The organic horizon at the surface of many soils, composed of organic detritus in various stages of decomposition. ex: At the surface of many soils is a layer of of organic detritus such as leaves, needles, twigs, and even animal bodies, all at differing levels of decomposition. O horizon is most pronounced in forest soils and is found in some grasslands.

lithosphere

The outermost layer of Earth, including mantle and crust. ex: Brittle. About 100 km (60 miles) thick. Upper mantle= solid. Made up of several large and numerous smaller plates, which overlie the convection cells within the asthenosphere. Over the crust lies the thin layer of soil that allows life to exist on the planet. Crust and overlying soil= most of chemical elements that sustain life. Earth contains a finite number of resources and once we mine the ones that are easily obtainable, we need to use more energy to mine the ones deep= important to conserve and recycle mineral resources.

erosion

The physical removal of rock fragments from a landscape or ecosystem. ex: Usually the result of two mechanisms= Wind, water, and ice transport soil and other Earth materials by downslope creep under the force of gravity and= living organisms, such as animals that burrow under the soil. After eroded material has traveled a certain distance from its source, it accumulates.

subduction

The process of one crustal plate passing under another. ex: Where oceanic plates meet continental plates, old oceanic crust is pulled downward, beneath the continental lithosphere, and the heavier oceanic plate slide underneath the lighter continental plate.

texture

The property of soil determined by relative proportions of sand, silt, and clay. ex: Loam= 40 percent sand, 40 percent silt, and 40 percent clay (triangular diagram). Permeability= the ability of water to drain through a soil. Sand= easy for water to drain (dry) and roots to penetrate. The best agricultural soils= a mix of sand, silt, and clay but naturally different plants can live in virtually all types of soil. Soil texture can have a strong influence on how the physical environment responds to environmental pollution.

base saturation

The proportion of soil bases to soil acids, expressed as a percentage. ex Calcium, magnesium, and sodium= soil bases because they neutralize or counteract soil acids such as aluminum and hydrogen. Soil acids are usually detrimental to plant nutrition while bases tend to promote plant growth. All of the soil bases except sodium are essential for plant nutrition. If a soil has a high CEC, it can retain and release plant nutrients. If it has a relatively high base saturation, its clay particles will hold important plant nutrients such as calcium, magnesium, and potassium. 80-90 percent of organisms in soil= fungi, bacteria, and protozoa. Most organisms are detrivores in soil.

strip mining

The removal of strips of soil and rock to expose ore. ex: 2 kinds of mining occur on land: surface mining and subsurface mining. strip mining= surface mining. Used when the desired ore is relatively close to Earth's surface and runs parallel to it, as often is the case for deposits of sedimentary rocks such as coal and sand.

earthquakes

The sudden movement of Earth's crust caused by a release of potential energy along a geologic fault and usually causing a vibration or trembling of Earth's surface. ex: Earthquakes are common in fault zones. The plates can move up to a few meters in a few seconds.

plate tectonics

The theory that the lithosphere of Earth is divided into plates, most of which are in constant motion. ex: Alfred Wegner= world's continents had once been joined in a single land mass called "Pangea"= evidence= identical rock formations on both sides of the Atlantic ocean and fossil evidence= can find fossils of the same species on different continents separated by oceans. Earth's landmasses have existed in several different configurations over time.

e horizon

The zone of leaching or elevation that forms under the O horizon or, less, often, the A horizon. ex: In some acidic soils. When present it always occurs above the B horizon. When the E horizon is present, iron, aluminum, and dissolved organic acids from the overlying horizons are transported through and removed from the E horizon and deposited in the B horizon, where they accumulate.

mining spoils (tailings)

Unwanted waste material created during mining. ex: Strip mining= Miners remove a large amount of material and return the unwanted waste material back to the hole created during mining.

soil acids

see base saturation

soil bases

see base saturation