Transcript Weathering and Erosion Powerpoint

Weathering and
Erosion PowerPoint
Created By: Allison, Brianna, & Jade
Weathering
Weathering is the process where rocks and other
materials on the Earth’s crust are broken down.
Weathering is a slow yet continuous process that, as
a result, is hard to notice at times. But, peeling paint
and the contrast between bright red, sharp edged
bricks and dull red, smooth edged bricks are a few of
the places where weathering is very noticeable and
easy to pick out.
Mechanical Weathering
• Mechanical weathering is when
rocks are broken down into
smaller shapes and pieces that
will eventually turn into soil.
• At the beginning of the
weathering process, the rocks
are sharp and angular.
• Eventually the rocks become
smooth and rounded as the
weathering process continues.
• All of the different agents
(causes) of weathering result in
the breaking down of rocks.
Agents of Mechanical Weathering
1. Temperature: During the day when the Sun is out, rocks become hotter and
expand. During the night when the Sun is no longer out, the rocks will become cooler and
contract. That continuous process is known as exfoliation and causes small pieces of the
rocks to flake off.
2. Frost Action: Water will go into cracks in rocks and when it gets cold enough
outside (32 degrees F or 0 degrees C), the water inside the rocks will freeze. That will cause
the water, and then the rock to expand, causing the rock to eventually break into pieces.
3. Organic Activity: Root-pry is when a plant starts growing in the crack of a rock,
and as it continues to grow, it will eventually cause the rock to break apart.
4. Gravity: Gravity will pull loose rocks and soil down a slope, causing a landslide where
the tumbling rocks will bump into other rocks on the way down and break into smaller
pieces.
5. Abrasion: Sand that is blown by wind causes abrasion where rocks are worn down
by particles that get carried by wind and water and scrape exposed rocks, making them
smoother.
Chemical Weathering
• Chemical Weathering is a type of
weathering where the chemical
makeup of rocks changes.
• During chemical weathering, rocks are
broken down in a process called
decomposition (process where dead
organisms are broken down), or
minerals are added or taken away from
rocks.
• Acid rain and pollution are two factors
of chemical weathering that cause the
most damage, as you can see from the
picture at the right.
Prince Edward’s Island
Agents of Chemical Weathering
1. Water: Water can do three main things: dissolve the crucial minerals in rocks that hold them
together, speed up the decomposition process using acids, and create a completely different
material when water is combined with certain minerals.
2. Oxidation: Oxidation is when oxygen combines chemically with some other substance,
eventually creating a new substance. Oxidation can actually create rust, too. So, chemical
weathering is caused by oxidation.
3. Carbonation: Carbonation is when chemical reactions occur between certain substances
and carbonic acid, which is an acid that comes from carbon dioxide when it dissolves in water.
Carbonic acid can be found in rain, that will seep into rocks on the ground and won’t actually do
too much damage, but it does slowly decompose certain rocks like limestone and feldspar.
4. Sulfuric Acid: Along with carbonic acid, sulfuric acid can be found in acid rain. But,
unlike carbonic acid that is a relatively weak acid, sulfuric acid is very strong and can wear down
rocks and even metal at a quick rate. Sulfuric acid is created from burning coal.
5. Plant Acid: So not only can plant acid be an agent of mechanical weathering, but it can
also be an agent of chemical weathering. Plants actually do produce acids, but similar to sulfuric
acid, plant acids are very weak. But, they do dissolve some minerals in rocks causing the rock to
break into pieces over time.
Erosion
Erosion is the process where weathered rocks
and particles of soil are moved over land. After
the rocks are broken down from weathering,
erosion carries that sediment and deposits it in a
new location. That process is called deposition,
and along with erosion, contributes to changing
the shape of our Earth.
Mount Saint Helens
Five Types of Erosion
Glaciers
Weathering
and Erosion
in New England
Gravity
• Gravity is what pulls down rocks and soil (sediment) down slopes
• That process is called mass wasting and it can happen quickly or
slowly. Landslides and mudslides are examples of mass wasting.
• A landslide happens due to an earthquake or volcanic eruption, and
is when soil, rocks, and boulders fall down a slope. It causes a lot of
damage in the end, as it moves anything in its path.
• A mudslide happens after heavy rain when rain turns soil into mud
and then mud starts flowing down hills. As it descends down hills,
the mud becomes thicker and thicker and pummels through
anything it reaches.
• Those two examples are slow examples of mass wasting.
Wind
• Wind is one of the most active agents of erosion, especially in beaches,
fields, and deserts.
• Loose materials on the ground in these areas are easily picked up by wind
and can land anywhere.
• Earth’s surface is eroded by wind in two ways: deflation and abrasion.
• Deflation is when loose sand, silt, and clay is moved by wind over short
distances.
• Abrasion is when larger pieces of sediment bounce along the ground as
they are moved by wind. As they do so, wear away rocks on the ground
that they hit by cutting and polishing them down.
• Wind forms sand dunes, which are large hills of sand deposited by wind.
• Wind also forms loess, which are fertile areas of silt and sand that were
blown by huge gusts of wind. They are the particles that didn’t get
deposited in sand dunes.
Glaciers
• A glacier is a huge piece of ice and snow that moves, and this type
of erosion is one of the most powerful types.
• Ice from glaciers is eroded by being plucked away from the rocks
underneath it, and by the process of abrasion.
• When a glacier pummels through a valley, anything in its path is
taken with it. Those rocks, boulders, and anything else in its path is
called glacial debris.
• As the glacier moves with this load of debris, the surface of the land
it’s traveling over grinds and polishes down the land.
• So glacial erosion scrapes away anything it travels over and can
even form mountains.
Running Water
•
•
•
•
•
•
Running water is the major cause of erosion and has the biggest effect on our
Earth than any other type of erosion.
Rivers, rain, streams, and runoff (water that flows over the surface of the
Earth) are three types of running water that perform erosion.
When there’s a lot of rainfall, there is a greater amount of runoff. Runoff will
carry particles of clay, sand, and gravel over land downhill through the water.
That sediment will form grooves in the soil called rills that become wider over
time and will eventually form into gullies which are channels for runoff.
The amount of runoff is also affected by the amount of plant growth where
places with little plant growth have greater erosion since there are less roots
to hold soil in place.
The soil is what absorbs the water and causes the erosion.
Waves
• Waves are caused by earthquakes, tides, and winds.
• They are very powerful and are constantly changing the shape of
shorelines through erosion.
• There are many ways that waves erode away the shoreline.
• They carry small rocks and sand that chip off pieces of the
shoreline.
• When water is forced into cracks along the shoreline, the increased
pressure makes the cracks become larger and eventually break.
• Salt in water dissolves rocks, which is another type of erosion.
• The size and force of the waves also affects the rate of
erosion.
Weathering and Erosion in New
England
Bibliography
Old Man of the Mountain
The Old Man of the Mountain was a granitic rock formation with the
profile of a face sticking out of a mountain. The Old Man of the
Mountain was located in Franconia Notch State Park in New
Hampshire in the White Mountains. It was formed an
estimate of 2,000 to 10,000 years ago and it was
formed at the end of the glacial period by glaciers
that were melting and rubbing up against the
Franconia Mountains (part of the White Mountains).
So the weathering of that mountain led to erosion
that formed a cliff that eventually eroded into the
Old Man of the Mountain. In May of 2003, the
renowned formation collapsed to the ground. Heavy
rains, high winds and freezing temperatures had
caused much wear on the mountain for a while
before it collapsed, so it had been reinforced with
cables and spikes, but they weren’t enough. All
of that weathering caused the cliff to be eroded
down to a much flatter mountain side.
Hurricane Bill
Hurricane Bill was the fifth largest Atlantic hurricane ever and
traveled along the eastern coast of the USA and Canada in
August of 2009. Hurricane Bill was a category 4 hurricane at one
point, but it started decreasing in intensity as it passed by
Bermuda, and continued to decrease during the rest of its
journey too. When it passed by Massachusetts, it was a category
1 hurricane, meaning it was the least intense and least
destructive of the five categories of hurricanes possible. The
hurricane caused severe rain in MA, that caused a great amount
of weathering, leading to changes in the Earth’s surface in those
areas along the coast and beaches. Erosion, especially in beaches
in New York, was a major factor of the hurricane that resulted in
the loss of some animal habitats, flooding, and much more.
Plum Island
On Plum Island, the extremely quick rate of erosion is
putting people’s homes along the coast in danger. Sand
deposits are supposed to go to the beach and replenish the
land with new sand. That sand will then make up for all the
lost sand from erosion, but for the past ten years, that hasn’t
been happening, therefore causing a major erosion problem.
Wind and water are also causing erosion along the beach
where loose sand that isn’t being stored by vegetation or
fences gets taken by the wind or water away from the beach.
Large waves that hit the beach remove sand from the beach
and carry it through the water.
Wilbraham Mountains
The Wilbraham Mountains, located in
Wilbraham, MA take up most of the
town. The Wilbraham Mts. were
formed by melting glaciers. The
mountains are made up mostly of
Amherst schist and much erosion of
the mountains hasn’t taken place
there in a while. During most of the
erosion, metamorphism would loosen
up rocks that would eventually tumble
down the mountains. On the east
side of this mountains range, part of
rock had been weathered to a gray
color. Back in the Triassic Period
(roughly 250 million years ago),
weathering and erosion carried
sediment into the Connecticut Valley
Lowlands. Today, the sediment is
made of akrose, sandstone, and shale
and is either a red or grayish color.
Global Warming
Global Warming is thought to be the cause of
increasing temperature, along with precipitation
and flooding in New England. In June 1998, the
record for the most rainfall in a year was broken,
causing rivers and streams to become much larger.
That caused the Earth’s surface to break down
through weathering and erosion and even led to
the closure of Logan Airport and a few highways at
one point. Vermont, New Hampshire, Rhode
Island, and Massachusetts each received more
than double their normal monthly rainfall. The
graph to the right shows how the temperature
increased over the past 30 years. In 2006, that
summer was the second hottest summer on
record in Massachusetts. That caused mechanical
weathering in Massachusetts, where rocks were
broken down, due to a cycle of heating and
cooling that leads to parts of the rock flaking off.
That caused a change in the earth’s surface.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
"Atmospheric CO2 Concentrations at Mauna Loa." Web. 25 Mar. 2010. <http://web.visionlearning.com/custom/geology/custom/rock_cycle_sketch.shtml>.
"CVO Website - Igneous Rocks." USGS Cascades Volcano Observatory (CVO). Web. 26 Mar. 2010.
<http://vulcan.wr.usgs.gov/LivingWith/VolcanicPast/Notes/igneous_rocks.html>.
"Decomposition -." Wikipedia, the Free Encyclopedia. Web. 26 Mar. 2010. <http://en.wikipedia.org/wiki/Decomposition>.
"The Five Major Causes of Erosion at Plum Island." Plum Island Beach Erosion Case Study by Michael Morris. Web. 24 Mar. 2010.
<http://www.plumislanderosion.com/major-erosion-causes.htm>.
"Google Image Result for Http://upload.wikimedia.org/wikipedia/commons/thumb/e/e6/GreenButton_RightArrow.svg/390pxGreenButton_RightArrow.svg.png." Google Images. Web. 22 Mar. 2010.
<http://images.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/e/e6/GreenButton_RightArrow.svg/390pxGreenButton_RightArrow.svg.png&imgrefurl=http://www.sherichseashells.com/product-tips/history-of-sterling-silver-jewelrycharms&usg=__aLm30VKdi8xG5lygyNMuEYlMxOY=&h=390&w=390&sz=43&hl=en&start=7&um=1&itbs=1&tbnid=9SBBnaFgYXh1pM:&tbnh=123&tbnw=123
&prev=/images%3Fq%3Dgo%2Barrow%26um%3D1%26hl%3Den%26safe%3Doff%26tbs%3Disch:1>.
"Google Image Result for Http://www.jwphotography.info/images/Back Arrow.jpg." Google Images. Web. 21 Mar. 2010.
<http://images.google.com/imgres?imgurl=http://www.jwphotography.info/images/Back%2520Arrow.jpg&imgrefurl=http://www.jwphotography.info/Portr
ait%2520Package%25204.htm&usg=__s58SpTbOx3uSsnDe4xDoB3ruIRY=&h=250&w=250&sz=10&hl=en&start=4&um=1&itbs=1&tbnid=UbRDGJq4BWOMd
M:&tbnh=111&tbnw=111&prev=/images%3Fq%3Dback%2Barrow%26um%3D1%26hl%3Den%26safe%3Doff%26sa%3DG%26tbs%3Disch:1>.
"Great 8 Science: The Changing Surface of the Earth." BC School Superintendents Association. Web. 20 Mar. 2010.
<http://bcssa.org/newsroom/scholarships/great8sci/Earth/Changing_Surface/Changing_Surface.html>.
"HOME." Oracle ThinkQuest Library. Web. 20 Mar. 2010. <http://library.thinkquest.org/20151/>.
"How Sedimentary Rocks Are Formed." Web. 29 Mar. 2010. <http://www.fi.edu/fellows/fellow1/oct98/create/sediment.htm>.
"Hurricane Bill (2009) -." Wikipedia, the Free Encyclopedia. Web. 25 Mar. 2010. <http://en.wikipedia.org/wiki/Hurricane_Bill_(2009)>.
"Igneous Rocks | Pictures of Intrusive and Extrusive Rock Types." Geology.com - Earth Science News, Maps, Dictionary, Articles, Jobs. Web. 18 Mar. 2010.
<http://geology.com/rocks/igneous-rocks.shtml>.
"Interactives . The Rock Cycle . Types of Rocks." Teacher Professional Development and Teacher Resources by Annenberg Media. Web. 16 Mar. 2010.
<http://www.learner.org/interactives/rockcycle/types.html>.
"Merrick History of Wilbraham, Massachusetts - 1963." Wilbraham Massachusetts 01095 - Community Website. Web. 23 Mar. 2010.
<http://www.wilbraham.com/history/athmerr.htm>.
"Metamorphic Rocks | Pictures of Foliated and Non-Foliated Types." Geology.com - Earth Science News, Maps, Dictionary, Articles, Jobs. Web. 18 Mar. 2010.
<http://geology.com/rocks/metamorphic-rocks.shtml>.
"Old Man of the Mountain -." Wikipedia, the Free Encyclopedia. Web. 27 Mar. 2010. <http://en.wikipedia.org/wiki/Old_Man_of_the_Mountain>.
"Old Man Of The Mountain." MUTHA'S MT WASHINGTON VALLEY HOME PAGE, North Conway New Hampshire. Web. 28 Mar. 2010.
<http://www.mutha.com/oldmanmt.html>.
"The Rock Cycle." Rocks, Minerals, Fossils and Earth Science Supplies. Web. 17 Mar. 2010. <http://www.rocksandminerals.com/rockcycle.htm>.
"Sedimentary Rocks | Pictures, Characteristics, Textures, Types." Geology.com - Earth Science News, Maps, Dictionary, Articles, Jobs. Web. 18 Mar. 2010.
<http://geology.com/rocks/sedimentary-rocks.shtml>.
"Sedimentary Rocks." Faculty and Staff, Georgia Perimeter College. Web. 24 Mar. 2010. <http://facstaff.gpc.edu/~pgore/geology/geo101/sedrx.htm>.
"Weathering and Erosion." Scarborough School Department - Home. Web. 19 Mar. 2010.
<http://www.scarborough.k12.me.us/high/projects/geoscience4/sbergg/erosion.htm>.
"Weathering Vs. Erosion." NPS: Explore Nature. Web. 24 Mar. 2010. <http://www.nature.nps.gov/geology/usgsnps/misc/gweaero.html>.