Weathering and Erosion
landforms created by wave erosion
-Sea stack -Sea arch -Sea cave
factors that affect chemical processes:
-acidity -chemicals used -temperature -surface areas
What five factors determine the amount of runoff in an area?
-amount of rain -vegetation -type of soil -shape of the land -how people use the land
deposits by waves
-beaches (longshore drift) -spits -sandbars and barrier beaches
Compare landslides and slumps
-both involve the movement of soil and rock downhill -landslides the rock and soil are loose -slumps the rock and soil moves as a single mass
Weathering
-breakdown of rocks -physical or chemical process -no movement -causes: ~atmoshpere ~living organisms ~water
What is chemical weathering?
-breakdown of rocks and minerals through chemical reactions -ex: weathering caused by carbonic acid
How does climate affect the rate of weathering?
-cold climates, the freezing and thawing that occurs causes rapid mechanical weathering through the process of ice wedging -warmer climates, chemical weathering is more rapid because the chemical reactions that dissolve rocks and minerals are accelerated by warm temperatures
construction and deconstruction forces
-erosion -sediment -deposition
Describe how a valley glacier forms
-form high in mountain valleys. because the temperatures rarely rise above freezing, ice and snow build up year after year. As more snow falls, the ice and snow below become compacted.
mass movement
-landslides -mudflows -slump creep
Erosion
-movement of broken down rock -physical process -requires movement of rock or something moving over the rock -causes/agents: ~running water (streams, rivers, etc) ~glaciers ~water
five agents of erosion
-wind -gravity -waves -running water -glaciers
all treatments
15 minutes
In Figure 7-2, which picture shows ice wedging: A, B, or C?
A
continental glacier
A large mass of moving ice and snow on land that covers much of a continent or large island
Present day glaciers are found primarily in _______________
Antarctica and Greenland
In Figure 7-2, which picture shows weathering that involves carbonic acid: A, B, or C?
C
What is one main difference between continental glaciers and valley glaciers?
Continental glaciers are much larger and thicker
Compare and contrast the way the two types of glaciers move
Continental glaciers can cover most of a continent or large island. As they move, they can spread out in all directions. In contrast, valley glaciers move down mountain valleys previously cut by rivers. The sides of mountains prevent valley glaciers from spreading in all directions as continental glaciers do.
A valley glacier spreads out over a large island or continent
F
Ice wedging is a form of chemical weathering
F
Mechanical weathering is more rapid in warm, wet climates
F
Mudflows are most common in swampy areas
F
Once the depth of snow and ice reaches more than 30 to 40 meters, the force of friction begins to pull a glacier downhill
F
Plants can only cause mechanical weathering
F
Sandbars are formed through erosion by waves
F
The process that lays down sediment in a new location is erosion
F
Millions of years ago, the Appalachian Mountains were towering, craggy mountains. Describe the processes that resulted in the lower, more gentle mountains that we know today.
Over millions of years, weathering broke down the rock in to small pieces. This process included both chemical and mechanical weathering. The small pieces of rock were then carried downhill by gravity and water.
How does the surface area of a rock affect the rate at which it weathers?
Smaller rocks have a larger surface area to volume ratio than larger rocks. This means that a larger proportion of the rock is exposed to the forces of weathering. As surface area increases, so does the rate of chemical weathering.
A spit is formed through wave deposition
T
Chemical weathering is probably faster along the Amazon River than in the Himalayas
T
Creep can occur on even very gentle slopes
T
water
The major agent of erosion that shapes the land surface of Earth
headland
a piece of land that juts out into the sea
moraine
a ridge-like deposit of sediment at the edge of a glacier
flood plain
a wide, flat area covered by water during flooding
The deposition of sediment where there is a steep drop-off into shallow, flat land can create a(n) __________
alluvial fan
The main factors that determine the amount of runoff in an area include the shape of the land, how people use the land, the type of soil, and:
amount of rain and vegetation
rate over weathering
amount remaining/time
plucking
as a glacier flows over the land, it picks up rocks in this process
Mechanical weathering ____
breaks apart rocks by physical processes
All of the following cause mechanical weathering EXCEPT ____
carbonic acid
How might small mammals cause weathering?
cause mechanical weathering as they burrow in to the ground. This breaks up sediment and pushes it to the surface. Once on the surface, other forms of weathering can act on the sediment.
very slow movement of rock downhill
creep
In the diagram, above, marker D is pointing to a __________, which is a landform that forms when a river slows down as it flows into an ocean or lake. As the river slows, it drops its sediment load, gradually creating a network of small channels and islands
delta
sediment
deposited material
Deltas are built up by
deposition
kettle
depressions left by melted blocks of ice in glacial deposits
amount remaining
easy comparison for rates of weathering
The process by which natural forces move weathered rock and soil from one place to another is called
erosion
Wind and water are agents of ____________________ that move sediment from one location to another
erosion
In areas where freezing and thawing occur frequently, rocks weather rapidly because of the ____ of freezing water
expansion
lowest % remaining
fastest rate
spit
formed through longshore drift
Mass movement is caused by
gravity
The force that moves sediment in a landslide or mudflow is ____________________
gravity
As rock is worn away by waves on a coastline, the land that takes a little longer to wear away can form a:
headland
How waves erode
headland
rate
how quickly something happens
The times in the past when continental glaciers covered large parts of Earth's land surface were the ____________________
ice ages
Which of the following is NOT an example of chemical weathering?
ice wedging in rock
After the last ice age, stranded ice blocks left behind by the continental glacier melted and formed
kettles
karst topography
landscape in which limestone is eroded to form deep valleys and caverns
most destructive kind of mass movement
landslide
As waves repeatedly hit a beach, some of the beach sediment moves down the beach with the current, in a process called ______
longshore drift
In the diagram, above, marker E is pointing to a __________, which is the "winding" shape that a river can take and its shape is determined by the hardness of the rock the flowing water meets
meander
A river flowing across a wide flood plain begins to form looplike bends called
meanders
In Figure 7-2, are the animal burrows in B an example of chemical or mechanical weathering?
mechanical
What material will oxidize when it is exposed to oxygen and water?
metal
Describe what a moraine is made of and explain how this glacial feature forms
moraine is made up of till, the mixture of sediment deposited by a glacier. A moraine forms when a ridge of till is deposited at the edges or at the lower end of a glacier. A terminal moraine forms at the farthest point reached by the glacier as the glacier begins melting back.
Glaciers can only form when
more snow falls than melts
In which of the following does the land being moved contain approximately 60% water?
mudflow
What causes a mudflow?
occur when soil that is usually dry become soaked with water. If the soil is especially high in clay content, mudflows con occur on very gentle slopes -earthquakes can also trigger mudflows
What occurs during a slump?
occurs when a large piece of a steep hill breaks away and falls
How do glaciers cause deposition?
occurs when glaciers retreat, leaving behind rocks and soil known as till
In the diagram, above, marker F is pointing to a __________, which are formed when meanders wear away at a narrow point and a pool of water forms
oxbow lake
Glacial erosion, the picking up and movement of earth beneath a glacier, is also referred to as ____________________
plucking
What processes lead to glacial erosion?
plucking and abrasion. Plucking is the process by which a glacier picks off rocks as it blocks over the land. The rock fragments freeze to the bottom of the glacier, gouging and scratching the bedrock as the glacier advances in the process of abrasion.
How are kettle lakes formed?
retreating glaciers often leave behind large chunks of ice in the soil. When these ice chunks melt, depressions in the landscape are left. Kettle lakes are formed when these depressions fill with water.
what chemical weathering called oxidation causes
rust
Both weathering and erosion produce
sediment
delta
sediment deposited where a river flows into an ocean or lake
A mass movement called ____________________ occurs when sediment suddenly slips downhill in one large mass
slump
Mass movement that involves rock and soil moving as a single unit
slump
groundwater
term used by geologists for water that soaks into the ground, fills the openings in the soil, and trickles into cracks and spaces in rock layers
deposition
the process by which worn away soil and rock settle out of the water
gradient
the rate at which something changes over a distance or time
erosion
the removal of soil and rock from one area to another
velocity
the speed of an object in a particular direction
As the energy of a wave moves through the water, what happens to the water particles themselves?
they move up and down, but do not move forward
The mixture of sediments deposited directly by a glacier is called ____________________
till
A stream or river that runs into another stream or river is called a
tributary
In the diagram, above, marker B is pointing to a __________, which is a small stream or river that runs into a larger stream or river
tributary
A kind of glacier called a(n) ____________________ forms when ice and snow build up in a mountain valley
valley glacier
What is the main agent of erosion that has shaped much of Earth's surface?
water
In the diagram, above, marker A is pointing to a __________, which is formed by water eroding away soft rock around harder rock, creating a steep drop-off
waterfall
Where a river flows from an area of harder rock to an area of softer rock, the softer rock may wear away, eventually forming a drop called a(n)
waterfall
