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Flashcards in Earth Science Final Deck (54):

What is the difference between mechanical and chemical weathering?

mechanical weathering is the breakdown of rock that takes place when a rock is broken into smaller pieces of the same material without changing its composition. chemical weathering is the breakdown of decomposition of rock that takes place when minerals are changed into different substances


What type of weather is most associated with each of the types of weathering?

chemical- warm, wet climates
mechanical- cold and wet or dry climates


what causes ice wedging?

when water freezes in the cracks of a rock and wedges it apart (because it expands)


How do plants mechanically weather rocks?

the roots plant themselves into the dirt in the cracks in a rock and as they expand it mechanically weathers the rock


How does particle size affect weathering rate

smaller particles will weather faster than larger particles because they have more surface area


describe the relationship between particle size and settling rate

if the particle size increases, then the amount of time it takes to settle in water decreases


what is found in each horizon of a soil profile

A Horizon- top soil, gray to black, contains humus decaying organics
B Horizon- subsoil, red/brown, clay and other minerals leach (wash) down from above
C Horizon- partly weathered bedrock


How is the thickness of a soil layer related to the weathering rate of the bedrock beneath it?

the faster the rate of weathering, the thicker the soil will be


What are the 4 agents of erosion?

gravity, wind ,ice (glaciers) water


What are the 3 ways that a river can carry sediment? What type of material is carried in each way?

solution-dissolved material
Suspension- fine material in turbulence
Bedlad- heavy particles dragged along bottom


Why do different areas of rock experience differential rates of erosion

A rocks resistance to weathering affects how fast it weathers. Limestone is easily weathered while granite and sandstone are much harder


What are the 3 stages of river development? What are the characteristics of each stage?

young, narrow Straight, v shape, fast water,, potholes, steep slope
mature, valley widens, flood plains starts , meanders begin, slower water, less slope
old, wide flood plains, slow water, bromeanders oxbow lakes, yazoos


Where do caverns form in Virginia? What is the bedrock in this area? What is the name for this type of top[ography?

caverns are in the valley and ridge province of virginia. the bedrock is limestone and it is known as karst topography


What is a divide? What is the largest basin in the United States and where are its divides?

high land that separates drainage basin


What are the layers of the groundwater system from the surface down?

zone of aeration, water table, zone of saturation


How does the type of surface material affect the rate of rainfall runoff

rainfall runoff is greatest for impermeable surfaces (like pavement and urban areas) and less for permeable surfaces (like farmland and forests)


Where do most earthquakes and volcanoes occur?

at plate boundaries (the ring of fire on the edges of the pacific plate)


WHat is evidence for plate tectonics?

earthquakes and volcanoes, sea floor spreading, pattern of magnetic reversal on the sea floor


What is the difference between a focus and an epicenter?

the point where an earthquake occurs is called the focus (origin)
an epicenter is the point on the surface above this place


What are the 2 types of seismic body waves? How did each one move?

P (primary) wave travels the fastest through any material.
Push-pull (compression)
S (Secondary) wave only travels through solids. Side to side


What causes plate movement? How does this behave at a divergent boundary? At a convergent boundary?

Convection currents ause plate movement. The currents rise an move plates apart at a divergent boundary.
They sink and pull plates together at a convergent boundary


How is continental crust different from oceanic crust

continental crust is older and thicker than oceanic crust


Describe sea floor spreading. Describe the age of the rock material on either side of the center.

Sea floor spreading occurs at mid ocean ridge. The newest ricks are close to ridge. As distance from a spreading center increase, the rocks get older..


What is the difference between magma and lava

magma is found below the surface and lava is usually on the surface


what is wegener's supercontinent called? Why didn't people accept his idea?

Pangea. Wegener did not explain HOW the continents could move


Which seismic wave travels the fastest? How do you find the distance to an epicenter?

P-Wave. Travel time graph


What is the law of superposition?

the oldest rock layers are on the bottom


AN unconformity is caused by a period of _______



What does the law of cross-cutting say

intrusions and faults are younger


In a conglomerate of sand and pebbles cemented together, what material is the oldest??

the sand and pebbles


What are the divisions of the geologic time scale? Why is time divided this way?

Eon, Era, Period, Epoch. These are determined by changes in dominant life forms which we learned from the fossil record.


What are the characteristics of an index fossil? What are they used for?

easily recognizable. Abundant. Wide spread. Short lived.
It is used to find a specific period of time


How are isotopes used to determine the absolute age of rock material?

Isotopes decay at a regular rate and we compare the amount of parent and daughter elements in a sample


WHat is a half-life? Does it ever change?

The time required for half of the remaining parent material to decay into daughter material. No


What type of information can fossils provide to scientists?

Fossils provide information about past climates and dominant species


What are the provinces of Virginia from the east cost to the west?

Coastal plain, piedmont, blue ridge, valley and ridge, appalacion plateau


Which province has limestone bedrock with caves

valley and ridge


Which province has coal

appalacian plateau


Which province has loose sand and gravel

coastal plain


Which province has oldest rock

blue ridge


which province has kyanite



List the layers in order form the surface upward

troposphere, stratosphere, mesosphere, thermosphere


When does condensation occur?

condensation occurs when the air temperature lowers to the dew point, usually in the early morning


What causes wind? How does it move? How are winds named?

Wind is caused by differences in pressure. It moves from high to low pressure and winds are named for the direction they come from


What is the Coriolis Effect? Why does it occur?

the Coriolis effect is the curving of wind and water to the right in the northern hemisphere and to the left in the Southern Hemisphere. It is caused by earth's rotation


WHat is necessary in order for clouds to form

in order for clouds to form the air temp must be at or lower than the dew point and condensation nuclei must be present


Where does a cT air mass form ad what are its characteristics? Where does an mP air mass form and what are its characteristics?

A cT air mass forms over land at low latitudes. It is warm and dry. An mP air mass forms over water at high latitudes. It is cold and wet.


When gasses in the atmosphere trap heat, the ___________ occurs

greenhouse effect


White feathery clouds are called _______. Puffy cotton-ball clouds are called ________

cirrus, cumulus


When water stays cooler than land and air moves form the sea to the land ______ occurs

sea breeze


The 2 main gasses in the atmosphere are _______ and _______

nitrogen and oxygen


What global winds blow over most of the US including our area? ________ How does this affect the movement of weather systems across the US?

prevailing westerlies.
Cause weather to move from west to east across the us


What is the cause of acid rain?

The combination of gasses, such as carbon dioxide and sulfur dioxide, with water vapor in the atmosphere results in acid rain these gases are the result of both natural and human activity. the gasses are released during volcanic activity and the burning of fossil fuels.. THese gases also build up in the atmosphere due to the upset of the carbon cycle from deforestation


How does acid rain affect the weathering of rock material?

increasing the weathering rate