Chapter 6 Geology and the Environment
________ are dynamic systems that transport water and provide energy and nutrients through this movement.
streams
In _______ mining, instead of creating one large pit in the ground, long narrow strips are dug out.
strip
When the ore is found in a wide area but it's not very deep in the ground, ________ mining is used.
strip
When too much groundwater has been pumped from the ground, the land actually lowers because gravity pulls it down into the space that the groundwater occupied previously. When this happens, the land has __________.
subsided
In ___________ mining, a long tunnel is created either horizontally or vertically. The tunnel walls are reinforced with wood and ventilation shafts are created to provide air to the miners underground.
subsurface
Some minerals are found very deep below Earth's surface - sometimes hundreds or thousands of feet deep! To remove these minerals from the ground, _____________ mining is used.
subsurface
__________ mining is actually less disruptive to the earth and produces less waste than __________ mining, but it's also much less effective and more dangerous.
subsurface; surface
The law of ______________ states that in any undisturbed sequence of layers of rock, the oldest or first-deposited layer would be on the bottom and the youngest would be on the top.
superposition
________ mining is removing minerals that are near the earth's surface because this is where the ore deposits are located.
surface
_________ water is what most people see as streams and rivers.
surface
What are the two main methods minerals are extracted from the earth?
surface mining and subsurface mining
Similar to contour farming is __________, which creates a series of platforms along a sloping edge to prevent runoff.
terracing
Groundwater occurs in _____. -soil moisture -the unsaturated zone -the saturated zone -floodplains
the saturated zone
Natural laws have remained the same throughout the history of the earth. The same natural laws that impact the earth today had the same impact millions of years ago. This describes which principle of geology?
uniformitarianism
One of the main principles of geology is _______________, which is the idea that the present is the key to the past.
uniformitarianism
Using the idea of ______________, we can deduce the order of geologic events that created a landform, like a mountain or a plateau, to know what happened.
uniformitarianism
The ___________ _____ is located just above the saturated zone. This area is not completely saturated with water, and there's still a significant amount of air in the soil.
unsaturated zone
Water erodes sediments and rocks that are __________ and deposits them ___________. This erosion may be caused by dissolved substances in the water that chemically erode rock material.
upstream; downstream
About how much of the Earth is water?
70%
Need to know: Groundwater comes from rainwater that has soaked into the ground, and the rainwater is naturally acidic because it reacts with carbon dioxide in the air.
As it meets with limestone in the ground, it partially dissolves the rock, and as this happens, unique features are formed.
Which of the following is NOT true of acid mine drainage? - It occurs from abandoned coal mines. -It separates the metals from the impurities -water involved contains metals & toxins -harmful components are picked up by rainwater
It separates the metals from the impurities.
What are tectonic plates?
Large pieces of the Earth's crust
_________ is the amount of salt in the soil, and this also needs to be maintained for healthy soils.
Salinity
__________ are cavities in the ground caused by erosion of limestone. They are usually funnel-shaped and open to the sky.
Sinkholes
What are two NATURAL effects of groundwater movement on the landscape? -erosion and abrasion -sinkholes and caverns -deltas and levees -subsidence and sinkholes
Sinkholes and caverns
Why does the Leaning Tower of Pisa lean?
The land below it has subsided.
The law of superposition states that in an undisturbed sequence of rock:
The oldest layers of rock will be at the bottom, and the youngest will be at the top.
Need to know: In open-pit mining, after the overburden is cleared from the ore, explosives are used to break up the ore material that is being removed from the ground, which is then taken away to be refined.
The size of the ore bed increases as mining continues, and eventually, the pit becomes a very large bowl-shaped hole in the earth's surface.
The principle of _____________ _________ states that any rock or fault that cuts across other rocks is younger than those it cuts across.
crosscutting relations
Erosion is a natural process, but it is also expedited by human activities, such as:
farming, logging, urbanization, commercial development
____________ are flat land areas surrounding a stream channel that flood with water and sediments from time to time. When they flood, sediments that were carried with the water are deposited along the stream banks and levees are formed.
floodplains
____________ is water below Earth's surface, in what is called the saturated zone.
groundwater
Even though ___________ is moving slowly underground, it can still cause some pretty drastic changes in landscape. Some of these changes are caused by humans, but most of the time, the changes are caused because ______ causes movement of the water.
groundwater; gravity
A __________ _________ is a drawn cross-section of a landform that clearly shows the layers that form it.
landform diagram
Studying this diagram can teach us many things about the landform and how it has changed over time.
landform diagram
Both groundwater and surface water shape the landscape and create _________.
landforms
____________ are very common in areas that have been logged because the land is so drastically altered that even something as small as a thunderstorm can wash incredible amounts of land downhill.
landslides
Which law of geography means that sedimentary rocks are originally formed in horizontal layers.
law of original horizontality
Two effective methods of preventing soil erosion are crop rotation and contour farming. How are these two methods different?
Crop rotation is about changing crops from time to time, while contour farming is a method that gives water time to seep back into the soil.
How is smelting most harmful to the environment?
It causes air pollution
___________ within soil are a main factor in soil health. Worms, bacteria, and fungi help break down decaying material and turn it back into healthy, nutrient rich soil.
Organisms
The Law of __________ __________ states that the layers will be formed in a horizontal manner
Original Horizontality
Need to know: In strip mining, the overburden is removed and piled up along the strip. Once the ore is removed, the overburden is dumped back into the strip.
While this may sound like a good method because the holes are re-filled instead of left open, the land actually looks more like a washboard after strip mining because of all of the re-piled soil.
If a region has been the subject of soil erosion and experts have suggested to use terracing, the area is most likely to be _____.
a hill
An unconformity is:
a surface of erosion that separates layers of rock.
Another type of erosion that occurs is when the moving sediments scrape the sides of the stream channels, called ________.
abrasion
Abandoned coal mines lead to _________________, which is water that is full of metals and toxins.
acid mine drainage
When dealing with coal mines, _______________ is much like hot water dripping through coffee in a filter, rainwater picks up the harmful components in the ground and carries them off as surface and groundwater runoff. This runoff can end up in streams, rivers and lakes that are nearby.
acid mine drainage
It's in this type of landscape that we find true underground rivers. The holes in the rocks are large enough to allow water to flow much faster than if it had to work its way through the soil.
caves and caverns
_______ and _______ are underground holes created by the dissolving of limestone. Rainwater moves through the cracks in the limestone and dissolves the rock as it flows through it. Cracks become larger, and this eventually creates large channels underground.
caves; caverns
_______________ is plowing and planting along the land's natural contours.
contour farming
_____________ is the practice of planting different crops each year to reduce nutrient depletion. Different crops use different soil nutrients, and by changing crops from time to time, the soil has a chance to recharge its nutrient load.
crop rotation
At the very end of the stream (where it meets a large body of water like a lake), the water slows so much that any remaining sediments are deposited, and this forms a ________. These are usually fan-shaped and are areas where land is continually being built as the deposited sediments progressively accumulate.
delta
Surface water benefits the land because it provides _______ and transports ________ and other materials.
energy; nutrients
_________ is when soil is transported and removed by water or wind.
erosion
Subsurface mining is _____ disruptive to the earth and produces _____ waste than surface mining.
less; less
Floodplains are flat land areas surrounding a stream channel that flood with water and sediments from time to time. When floodplains flood, sediments that were carried with the water are deposited along the stream banks and _______ are formed.
levees
Natural changes in the landscape from groundwater often come from the interaction of groundwater and ____________.
limestone
One method of subsurface mining is ___________ mining, which is when coal is sheared from the wall and collected on a conveyor belt, much like a potato peeler shears away layers of a potato. This is a very efficient way of extracting coal from an underground mine.
longwall
The ________ is the thick, mostly solid layer of the Earth between the crust and the core.
mantle
_________ are inorganic compounds, such as ores(copper) and precious stones(diamonds)
minerals
___________ is how minerals are removed from the ground
mining
Which of the following is NOT an effect of erosion? -air pollution -water pollution -landslides -more land for homes
more land for homes
Most effects of groundwater movement are _____. -caused by acid rain -naturally influenced -human influenced -caused by abrasion
naturally influenced
_____________, which is when crops are replanted without tilling the ground and therefore without disturbing the lower soil layers.
no-till farming
In surface mining, when the ore deposits are very large, ____________ mining is utilized. A large, open pit is created as machines scrape off any earth that is not ore and set it to the side.
open-pit
In open-pit mining, a large, open pit is created as machines scrape off any earth that is not ore and set it to the side. This material is called ____________, and as the ___________ is scraped off, it's piled into _______________.
overburden; overburden; spoil banks
In _________, the mantle wells upward because of the convection and elevates the edges of spreading oceanic plates.
ridge push
When the mantle pushes the edges of a tectonic plate higher, gravity can pull downward on it, causing the plate to move. This is known as what?
ridge push
The __________ _____ is the region underground where water completely fills any open spaces.
saturated zone
A __________ is formed because the groundwater caves in on itself, but they can also be formed from excessive groundwater removal.
sinkhole
As the leading edge of a tectonic plate moves back into the Earth, gravity can assist its movement downward. This is known as what?
slab pull
In _________, gravity is pulling on the front part of the plate; in __________, it is forcing movement from the back end.
slab pull; ridge push
This process in mining, separates the impurities from the metal, but also creates air pollution because gases that are created as by-products (such as sulfur dioxide) may escape and reach the air.
smelting
____________ is the process of heating ores to release the metals in them.
smelting
______ is a mixture of mineral and organic material that covers Earth's surface. It is very complex, takes a very long time to form, and is incredibly important to sustaining life on Earth since it is where decaying material is recycled into usable nutrients.
soil
________ also needs to be monitored and maintained. It is the measure of how acidic or alkaline a soil is.
soil pH
One method of subsurface mining is _________ mining, which is when hot water is injected into the ore to dissolve it. Once the ore is dissolved, air is pumped into it, and it's bubbled up to the surface.
solution
Uniformitarianism states: -all layers of rock are uniform -everything remains unchanged -the present is key is the past -the oldest rocks would be on the bottom of a rock formation
the present is key to the past
The process by which heat from the Earth's interior causes magma to rise and sink is known as what?
thermal convection
With _____________, liquid rock near the mantle is heated and rises toward the crust. The rock near the surface is cooler and sinks back down toward the core.
thermal convection
________________ is when heat from the core of the Earth is transferred to the surface of the Earth by the mantle.
thermal convection
As the leading edge of a tectonic plate is forced back into the mantle, a small convection current forms beneath it, pulling it downwards. This is known as what?
trench suction
What are the two ways soil is removed from the land?
wind and water
____________ are often used in agriculture to prevent soil erosion and are just what they sound like: areas that reduce wind exposure to crops.
windbreaks