ESC1000 Exam II

Describe four ways that matter interacts with light and other radiant energy.

1. Transmission- gas molecules do not affect radiation, 2. Reflection- evenly spread in predictable directions, scattering, absorption- causes heating increased vibrations 3. Emission - Emission lines show up as narrow bright bands in the spectrum. Each emission line corresponds to the wavelength of the energy emitted by a specific element within the radiation source. 4. Absorption - If the radiation emitted by a source gets absorbed by a material between the source and the Earth, distinct wavelengths of the radiation do not reach the Earth. When this happens, the spectrum displays dark bands, called absorption lines, at specific wavelengths.

Define the atomic mass and atomic number of an atom

Atomic number - The number of protons in an atom Atomic mass - The protons plus neutrons in an atom

Describe the differences between chemical and clastic rocks

Clastic (breccia, conglomerate, sandstone, siltstone,shale) once separated clasts that cemented to another (weather→ erode→ deposit→ lithification)mechanical weathering Chemical rocks (salt, iron ore, chert, flint, some dolomites, limestone) form when dissolved minerals precipitate from solution

Describe what is recorded by ripple marks and cross-bedding

Ripple marks-are sedimentary structures and indicate agitation by water (current or waves) or wind Cross-bedding- represent preserved slip faces of dunes or ripple marks( /// \\\)

What is the difference between emergent and submergent coastlines? What features are associated with each?

emergent coastlines-a coastal location where the land is rising relative to sea level, wave erosion produces a wave cut platform along it as land rises platform becomes a new terrace submergent coastlines-Coasts where the land is sinking relative to sea level, river drain valleys and deposit sediment on coastal plain along it, as land sinks sea level rises ad floods the valleys, wave erodes headlands

What does zero degrees in the Kelvin scale represent?

· Absolute 0, lowest possible temperature, no heat energy remains in a substance, -273 C

Explain why climates are generally cooler at the poles and warmer near the equator

· Because they are further from the sun

What is regolith and how does it form?

○ Lunar regolith is the loose material on the moon's surface, including micrometeorites, dust from space weathering, pulverized rock from impacts,

Describe the effect of dams on beaches

● Dams increase erosion in local beaches, making them narrow significantly.

What are the average densities of the Earth and Moon?

● Earth: 5.51 g/cm3 ● Moon: 3.34 g/cm3

Explain how tar sands form? How is it extracted?

● Tar sand reserves form when sandstone acts as a reservoir rock, and its pores contain hydrocarbons. However, they are too viscous to flow, so they cannot flow out of the sandstone's pores. It is extracted by heating the hydrocarbons at close to surface and far from surface Then they force steam or solvents down injection wells to liquefy the oil, then pump the oil up from extraction wells.

What is meant by the "near" side of the moon?

● The lunar hemisphere that is permanently turned towards Earth

Describe how the elevation of the groundwater table varies under hills and valleys

● The water table lies at a higher elevation beneath hills than beneath valleys.

Define an isotope

● a form of the same element that contains equal numbers of protons but different numbers of neutrons in their nuclei

Explain the causes of tides and describe the positions of the earth-moon-sun when tides are highest and lowest

(1) the gravitational attraction of the Moon and the Sun, and (2) centrifugal force caused by the revolution of the Earth-Moon system. Strong tides when moon and sun are aligned Weak tides when they are at right angles of each other

Explain how the parent:daughter ratio and fraction of remaining parent change as multiple half-lives pass

16:0, 8:8, 4:12, 2:14, 1:15

Describe the conditions needed to form mudcracks

An environment in which sediment got wet and then dried out

Describe what the atmosphere is, including the different components found in the atmosphere.

Atmosphere is a thin envelope of gas that provides O2, controls temp variations, needed to have a climate (Wind, rain etc) Nitrogen:78%, O2: 21%, Argon: .934%, CO2: .0389% (it's a greenhouse gas has the biggest effect on climate) (Other: NE,He, CH4,Kr,H2) Variable components: 0-4% H20 and contains man made and natural aerosols

Explain how climate differs from weather

Averages and variations of temperatures over the course of a year are one aspect of the region's climate.

Explain how loose sand grains may become lithified into a cohesive rock

Compaction is a consolidation of sediments due to the intense pressing weight of overlying deposits. ... Cementation is the process by which dissolved minerals crystallize and glue sediment grains together.

Explain the concept of energy density (p. 347-348) and rank different energy sources by their energy density

Energy stored per kilogram HIGHEST Uranium, Gas, propane, coal, wood, gunpowder, lithium battery, lead acid battery LEAST

Describe the factors needed to create evaporates such as salt

Evaporites are precipitated in areas where temperature are very high, humidity is low, and evaporation exceeds precipitation,

How old are the absolute ages of the two rock types (terrains)? What are the ages of the Feldspar-rich highlands and Mare basalts with respect to the period of heavy bombardment?

Feldspar-rich highlands are 4.46 to 4.2 billion years old (heavily cratered) Dark Basins/Maria Basalts are 4.2 to 3.1 billion years old (much less cratered and few volcanic domes and cones Period of Heavy Bombardment was 4.5 to 3.8 billion years old

What is the period of heavy bombardment and how is recorded on the moon? How is this period used to estimate the age of planetary surfaces?

From about 4.5 to 3.8 billion years ago, failed planets and smaller asteroids slammed into larger worlds, scarring their surface and generating craters. Near the end of this, during the period known as Late Heavy Bombardment, impacts in the solar system increased. Scientists utilize both the size and and number of impact craters on a surface, as well as how eroded they are, to determine the age and histories. Older surfaces have more impact craters.

Describe possible problems with overpumping of groundwater from wells

If you pump water out of the well too fast, the water table sinks around the well—a phenomenon called drawdown. This eventually forms a cone of depression. The overpumping of wells can cause the underlying salt water to rise into the wells and contaminating the freshwater aquifer.

Describe the relationship between lake levels and the water table

In Depressions or channels where the ground surface lies below the water table, the low area fills with water and becomes a lake or stream in such places the surface of the lake or stream represent s the water table.

What is the Montreal Protocol of 1987 and what was its result on Ozone levels and size of the Ozone hole.

It banned the production and use of CFCs size of hole decreasing

Define the Law of Superposition

Law of superposition, a major principle of stratigraphy stating that within a sequence of layers of sedimentary rock, the oldest layer is at the base and that the layers are progressively younger with ascending order in the sequence.

Describe how and why atmospheric pressure changes vertically through the atmosphere

Most gas molecules concentrated near Earth's surface due to gravitational pull

Explain what Ozone is, how it forms, and where it is found within our atmosphere.

Ozone is O3 naturally produced in the stratosphere by a two- step reactive process. In the first step, solar ultraviolet radiation (sunlight) breaks apart an oxygen molecule to form two separate oxygen atoms most in stratosphere (in troposphere as pollution)

Explain why depletion of Ozone concentrations are harmful to us and describe how human activity can deplete Ozone levels.

Ozone layer in stratosphere protects from harmful UV rays from the sun (Most harmful being UV-C) Ozone depletion occurs when chlorofluorocarbons (CFCs) and halons—gases formerly found in aerosol spray cans and refrigerants—are released into the atmosphere

Describe the difference between physical and chemical weathering

Physical weathering happens when rock is broken through the force of another substance on the rock such as ice, running water, wind, rapid heating/cooling, or plant growth. Chemical weathering occurs when reactions between rock and another substance dissolve the rock, causing parts of it to fall away.

Describe how coal forms, how it is transformed during burial and heating, and the resulting different types/ranks of coal

Plants die and fall into stagnant water of a swamp. This water lacks O2 so the dead biomass does not rot away entirely and new plants grow on top of it. Eventually a layer of compacted organic material know as peat accumulates. If a layer of peat becomes deeply buried by overlying sediment it can be preserved over geologic time. When overlying sediment becomes thick enough the organic matter in peat undergoes compaction and heating. Slowly chemical reaction that releases volatile compounds transform peat into a dark brown to black brittle sedimentary rock called coal. The various forms are based on how much enriched carbon a piece of coal has. Once the carbon concentration is over %60, it can be called coal. ● Lignite - < 100C/ 60%-70% 18MJ/kg ● Bituminous - 100C-200C/ 70%-87%/ 27Mj/kg ● Anthracite - 200C-300C/ 87%-95%/ 33MJ/kg

Explain the difference between porosity and permeability

Porosity - The total volume of empty space (pore space) in a material, usually expressed as a percentage. Permeability - The degree to which a material allows fluids to pass through it via an interconnected network of pores and cracks.

Calculate the age of a material given the daughter:parent ratio and the length of the half-life

See how many half lives have passed and then use the length of the half life to determine age.

Explain the differences between shale, sandstone, and conglomerate/breccia

Shale- very fine, mud, mostly clay sandstone- medium size clast, sand, mostly quartz conglomerate/breccia-very coarse, gravel, angular/rounded

Explain how the Earth's first semi-permanent atmosphere formed and how its composition changed over time (and why)

The earth's first atmosphere was most likely hydrogen and helium, as that was what was around the sun and its planets when it first formed. Eventually, earth's crust formed many volcanoes which released steam (H2O), CO2, and NH3. The CO2 in the atmosphere was dissolved in the water and the bacteria in it created O2. As oxygen was being added into the atmosphere, the NH3 molecules were broken up by sunlight, separating the Nitrogen and Hydrogen. Most of the hydrogen floated to the top and was released into space, which is why there is a lot of nitrogen in our atmosphere.

Explain the difference between erosion and weathering

The main difference between weathering and erosion lies in where the process takes place. Weathering degrades a rock without changing its location. Erosion, on the other hand, causes rocks -- or particles of rock -- to be carried away from their original locations and deposited elsewhere. Weathering often leads to erosion, breaking down the rock into small pieces that are easier for wind and water to carry away.

Describe what is meant by the oil age, the factors that go into estimating how long the oil age will last, and the time estimates before oil supplies run out.

The present time is the oil age because of how much the world's economy depends on oil. 3,700 billion bbl of conventional oil reserves. The world consumes 34 billion bbl per year. Conventional oil supplies may only last for about another year. However, there is 1.5 trillion bbl in tar oil, 4.5 trillion bbl in oil shale, and 500 billion in tight oil. These supplies will last another few hundred years.

Describe the patterns of sea level change over the last 500 my (e.g., Q21 on Reading activity and PPT lecture)

The sea levels has risen and fallen multiple times.

Explain the effects of scattering of visible light on optical effects such as sky color and darkness of shadows

The sky looks blue because the atmosphere scatters wavelengths in evening sky looks orange/purple because visible light traveling from the sun have to cross more of the atmosphere With no atmosphere and light scattering, shadows are darker

Explain the motion and driving forces of thermohaline circulation in the oceans

Thermohaline circulation begins in the Earth's polar regions. When the water gets very cold, sea ice is formed. As a consequence, the surrounding sea water gets saltier because as sea ice forms, the salt is then left behind. As the water gets saltier, it also gets denser and starts to sink. Surface water is then pulled to replace the sinking water when it becomes cold and salty enough to sink. This initiates the deep-ocean currents driving the global conveyor belt.

What are bright rayed craters and how old are they with respect to other moon features such as the Maria and highlands?

They are craters that have theses bright white rays streaming out away from the point of impact. They are younger than all the other moon features.

Explain what is meant by transgression/regression and describe the vertical sequences of rocks that forms during transgressions

Transgression-coastline migrates inland position of the beach moves inland involves a relative rise in sea level to the land and the shoreline moves toward higher ground deepening upward sequence Regression- continental sediments are being deposited farther out to sea than they once were. Therefore, we see a sequence (from bottom to top) of: limestone ► shale ► sandstone. A maximum regression occurs where the coarsest sediments reach the farthest seaward.

Explain what is meant by the Greenhouse effect and how greenhouse gases contribute to heating of planetary atmospheres.

When the Sun's energy reaches the Earth's atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases, more greenhouse gases more trapped heat

Explain ways in which sinkholes form.

When water flows underground, it gradually dissolves limestone to produce caves. When the roof of the caves begin to collapse, circular depressions called sinkholes form.

What are carbon dioxide sink/sources and identify potential sinks/sources on Earth

carbon dioxide sink is something that takes away carbon dioxide and a source is a source of it

Describe how temperature controls the range of electromagnetic radiation (EMR) wavelengths emitted by a body. Compare types and wavelengths emitted by the Earth and Sun

· A warmer object emits more radiation, at all wavelengths, than a colder object. · The total amount of radiation an object emits increases rapidly as its temperature increases. As the temperature of an object increases, the wavelength of maximum radiation emission shifts toward shorter wavelengths. Short=hot // long = colder

Identify the boiling and freezing points of water in the Celsius and Fahrenheit scales.

· Boiling - 100C/212F · Freezing - 0C/32F

Summarize the electromagnetic spectrum, indicating the relative order of different types and wavelengths of EMR on the spectrum.

· Gamma, X, Ultraviolet, Visible, Infrared, Microwave, and Radio

Describe unconventional fossil fuels

· Geologists recognize three types of unconventional reserves: · (1) Oil shale reserves consist of organic-rich source rock that became warm enough for kerogen to form, but not for oil or gas to form. · (2) Tar sand reserves consist of sandstone whose pores contain hydrocarbons that are too viscous to flow. · (3) Tight oil and tight gas reserves consist of source rock in which kerogen warmed enough to transform into oil and gas, but could not migrate away.

Describe how global temperatures have changed over the last ~140 years

· It has gradually increased over the last 140 years

Describe the motion of ocean waves, including changes with depth below the ocean surface

· Motion of ocean waves is circular. The diameter of the circle is greatest at the oceans surface. With increasing depth the diameter of the circle decreases.

Define gyres as it pertains to ocean surface currents. Sketch and explain the main patterns of ocean currents in the Northern Hemisphere versus those in the Southern Hemisphere

· Surface currents that display circle like paths. Northern Hemisphere is clockwise and the Southern Hemisphere counter clockwise.

What are the main sources of anthropogenic carbon dioxide

· The main source is carbon dioxide that humans burn through fossil fuels, concrete productions, deforestation and industrial output Another source would be methane that is burned in fossil fuels, leaking of these natural gasses in oil and gas fields, landfill decay, and livestock flatulence

Explain the formation and characteristics of rip currents

· Waves push water toward the shore at constant rate. As the backwash moves back to the sea, it may concentrate into a strong seaward flow, called a rip current

Explain how continental glaciation, rates of seafloor spreading, ocean temperatures, and position of the continents affect sea level.

· contiental glaciation: when glaciers and ice sheets are extensive, they tie up large volumes of earth's water causing sea level to drop. When ice sheets & glaciers melt, they release large volumes of water that flow back into he ocean causing sea level to rise · rates of seafloor spreading: a decrease in the spreading rate causes sea level to fall · faster spreading yields more young seafloor ad young seafloor is less deep tan older seafloor raising the sea level. · Ocean temperatures:when ocean temps fall, water in the ocean contracts causing sea level to fall, when ocean temps increase, water in the ocean expands slightly causing small rise in sea level position of the continents: in the past widespread glaciation occurred when one or more continents were near the poles. By allowing glaciers to exist, continents at high latitudes can cause a drop in global sea level. in past larger continents were not so close to the poles. this lower latitude position of continents minimized or eliminated widespread glaciation tending to keep sea levels high.

Explain the problems with obtaining and age when (1) a young material is dated with an isotope with a long half-life, and (2) an old material is dated using an isotope with a very short half life"

•1) young material hasn't gone through a half life yet •2) Old material has gone through all of them

What are the anorthositic highlands and Mare basalts? What are rock types s on the moon and what type of land surfaces do they form? How did each form?

○ Anorthositic Highlands- Terra (earthy), mostly feldspar made of nonferromagesium creating the light color, heavily cratered, surface is very old, Ca ruch silicate minals (4.46-4.2 billion yr old) ○ Mare Basalts- Maria (Seas), dark colored basins from fermagensium, created from lava with low viscosity flows easily into deep impact craters creating a flat surface with few domes and cones (4.21-3.1 Ga)

Briefly describe the most popular theory for the formation of the moon?

○ Based on analysis of room rocks, it's believed the moon formed from debris ejected into orbit around the Earth after the Earth and protoplanet Theia collided (4.53 Ga)

What is the effect of fetch on wave properties

○ Fetch of the wind- the distance over which it blows ○ Some energy of the wind blows the tops of the waves over, causing water to mix with air and resulting in whitecaps.

Identify the characteristics of rogue waves

○ Rogue wave- an isolated wave that rises more than twice as high as most large waves passing a locality during a specified time interval

Explain what drives surface ocean currents

○ Surface currents begin because of the frictional interaction between moving air and the surface of the sea. But the specific path that a current follows depends on the influence of two other forces—the Coriolis force and the pressure-gradient force—and on the shapes of ocean basins.

Explain how the ocean currents affect the climate of northern Europe

○ The current moves along the U.S. East Coast across the Atlantic Ocean towards Europe. The heat from the Gulf Stream keeps much of Northern Europe significantly warmer than other places equally as far north.

Describe storm surge

● A storm surge is a rise in local sea level (above normal tide level) that develops in response to a storm and when strong winds push the sea into a mound. ○ Storm surges are particularly high during hurricanes. ○ When a storm surge reaches the coast at the same time as high tide and is accompanied by high waves, sea level temporarily becomes so high that ocean water can inundate land far inland of a beach. ○ In a matter of hours, a storm can radically alter a beach, leaving it as a skeleton of its former self.

Define aquifer and aquitard. Identify characteristics that make good aquifers and aquitards

● An aquifer is a rock or sediment that transmits water easily. ○ There are two types of aquifers. ■ If an aquifer is unconfined, that means it starts at the ground surface and extends downward. ■ If an aquifer is confined, that means it is separated from the ground surface from an aquitard. ○ Good aquifers have high permeability and high porosity. ● An aquitard is a rock or sediment with low permeability regardless of porosity. It does not transmit water easily and it slows the movement of groundwater. ○ Good aquitards have low permeability and low porosity.

What is an artesian well and what features are needed for one to develop?

● An artesian well is a well in which water rises without pumping due to pressure within a confined aquifer. ○ There are two types of artesian wells. ■ If the level to which the water table would rise lies below the ground surface, the well is a non flowing artesian well. (shown near the left side of the image above) ■ If the level lies above the ground surface, the well is a flowing artesian well —the water from such a well actively fountains out of the ground. (shown near the right side of the image above) ○ Artesian wells exist where the recharge area for the confined aquifer lies at a higher elevation than the site of the well, so that if the aquifer were not confined, the water table would be higher.

Describe solutions for beach erosion

● Beach nourishment (pictured above) ○ The process ■ First half (shown by left image): A dredge is brought offshore. The hydraulic dredge uses powerful vacuum pumps to suck sediment off the substrate, which it stores in its hull. Once filled, the dredge brings the sediment to shore. ■ Second half (shown by right image): A buoy is placed to serve as an anchor for a floating pipeline that reaches from offshore to the beach. The dredge pumps the minded offshore sediment onto the beach. Pipes are laid onshore to continuously supply bulldozers with new sediment. Finally, the bulldozers distribute the sediment along the shore. ○ Pros ■ Doesn't require the building of ugly rocky structures on the beach ■ Significantly widens the beach ○ Cons ■ Expensive ■ Temporary ● Groins (pictured above) = walls of rock and cement that run perpendicular to the beach into deeper water. ○ Cons ■ Reduces amount of sediment brought to the beaches downstream of the longshore current ■ Expensive ■ Groins beget groins ● Beach becomes a zig zag pattern ● Whoever cannot afford to get a groin ends up experiencing even more rapid erosion rates. ● Eventually, their houses are quickly undermined by erosion, so they have to abandon their houses ● Breakwaters (pictured above) = thick walls of rock and cement that run parallel to the beach ○ Pros ■ They block incoming wave erosion of the beach + disrupt the longshore current ■ Beach accretes behind each breakwater ○ Cons ■ Dangerous currents form around the breakwaters, requiring that swimmers stay away from them ■ They ruin the ocean view

Describe the conditions that favor the development of sinkholes and other karst features

● Drought, along with resulting high groundwater withdrawals, can make conditions favorable for sinkholes to form. Other conditions that promote karst development are well-jointed, dense limestone near the surface; a moderate to heavy rainfall; and good groundwater circulation.

Compare the rotation rate of the Moon and its period of revolution around earth.

● Earth: 5.51 g/cm3 ● Moon: 3.34 g/cm3

Describe geothermal energy

● Geothermal energy is heat that comes from deep in the Earth's surface. Steam can carry this energy to the surface, and it can then be harnessed by a power plant to power generators, which convert that energy into things like electricity. It is renewable because heat is continuously produced within the Earth, and will not run out as long as the Earth's core produces heat.

Describe the effect of groins on beach accretion

● Groins (pictured above) = walls of rock and cement that run perpendicular to the beach into deeper water. ○ Cons ■ Reduces amount of sediment brought to the beaches downstream of the longshore current ■ Expensive ■ Groins beget groins ● Beach becomes a zig zag pattern ● Whoever cannot afford to get a groin ends up experiencing even more rapid erosion rates. ● Eventually, their houses are quickly undermined by erosion, so they have to abandon their houses

Explain how petroleum/hydrocarbons form including the significance of source rocks, reservoirs, and traps

● Hydrocarbons mostly form from the remains of plankton and some forms of algae. At high enough temperatures, between 50 and 90 degrees Celsius, organic chemicals in dead plankton transform into molecules of kerogen. b/t 90to160 kerogen molecules break into oil and gas molecules and then above that they form natural gas. Migrates to reservoir rock for conventional drilling.

What is meant by drawdown and cone of depression around a well and why does this form?

● If you pump water out of the well too fast, the water table sinks around the well—a phenomenon called drawdown. ● After drawdown occurs, the water table forms a downward-pointing, cone-shaped surface called a "cone of depression" surrounding the well.

Describe the differences in interactions between streams and groundwater in arid vs. humid regions

● In humid regions, the water table lies within a few meters of the surface. In such regions, streams/lakes/ponds remain filled and the surface of the stream/lake/pond represents the water table. ● In arid regions, the water table lies hundreds to thousands of meters below the surface. So, in these regions, bodies of water may dry up. Water that collects temporarily in low areas seeps down until it reaches the water table.

Describe how stalactites, stalagmites, and columns form

● In many locations, groundwater drips from the ceiling of a cave or flows along its walls. As the water evaporates, calcite precipitates. Over time, this calcite builds into cave formations, or speleothems, such as stalactites, stalagmites

List two factors that must be taken into account when choosing an isotope to date a material

● Must know what material you want to date and age of material vs half life of isotope

Explain what is meant by an unconformity and illustrate each of the three different types

● Nonconformity-sedimentary rock overlie generally much older igneous rock, go thru cooling/ erosion prior to becoming substrate/ base where sediment accumulate, granet exposed ● Disconformity-under shallow sea, sea level drop and show beds, no sediment added, sea level rises and new sediment over old ● Angular-rock below angular are tilted/folded before the conformity develops and cut across layers

Define the three particles that make up an atom, including their masses, charges, and location within the atom

● Proton (+,1 mass), Neutron(/, 1 mass) both in nucleus, Electron (-, 0 mass) electron shells outermost region, including their masses, charges, and location within the atom

Explain the process of radioactivity and the concept of a half-life

● Radioactivity- radioactive isotopes are unstable and give off subatomic particles that change atoms' elements. ● Half-life- the time it takes for half of a group of atoms to decay

What is the size of the Moon? Compare with the size of Earth.

● Radius: 1,079.4 mi ● The moon is a bit more than one-fourth (27 percent) the size of Earth, a much smaller ratio (1:4)

Describe and identify renewable and non-renewable resources

● Renewable resources can be replaced by nature within months to decades. These include hydropower, wind energy, solar energy, and geothermal energy. Nonrenewable resources can take centuries to millions of years to replenish. These include oil, coal, natural gas, and nuclear energy.

List the major components that make ocean water "salty". What is the average salinity of the oceans?

● Sodium and chloride are the major components. The average salinity of the oceans is 3.5%.

Define the four principles of relative dating

● Superposition (the oldest rocks are located on the BOTTOM of undisturbed rock layers) ● Original Horizontality (Sedimentary rock layers always begin in a horizontal position Horizon = parallel to the ground) ● Cross-Cutting Relationship (anything that cuts across rock layers is younger than the rock layers it cuts through) ● Unconformity (a gap forms in a series of rock layers due to erosion)

Describe the process of extraction of hydrocarbons

● The potentially extractable oil and gas is in hydrocarbon reserves. Hydrocarbons that can be extracted easily are in conventional reserves. Hydrocarbons that can't be extracted easily are in unconventional reserves. The extraction process relies on seismic-reflection profiles to identify hydrocarbon-bearing strata underground. A vibrating truck sends seismic waves and these reflect off rock layers and return to the ground level. Then, workers use a rotary drill to dig into the rock layers and penetrate the layer with the oil hydrocarbons or gas hydrocarbons.

Define the water table and the difference between the zone of saturation and the zone of aeration?

● The water table ○ The water table is the underground boundary approximately parallel to the Earth's surface that separates the zone of aeration from the underlying saturated zone. ● The zone of aeration (aka the "unsaturated zone") ○ above the water table + nearer to the ground surface ○ groundwater only partially fills pores, leaving some air-filled pore space ● The saturated zone ○ below the water table ○ groundwater completely fills the pores

How can over withdrawal from an aquifer lead to ground subsidence?

● When over withdrawal occurs, the rock compacts because the water is partly responsible for holding the ground up. When the water is withdrawn, the rock falls in on itself.