Transcript break rocks?

Breaking Down the Rocks
Weathering and erosion
Eric Angat
Teacher
Essential Question
How is Earth’s
crust shaped?
1. What is Karst topography?
is a landscape created by
groundwater dissolving
sedimentary rocks such
as limestone.
Karst topography refers
to underground caves.
Florida
A map of the United States showing regions displaying or having active karst
topography.
Topography is the study of the
shape and features of
the surface of the Earth. The
topography of an area could refer
to the surface shapes and features
themselves, or a description
(especially their depiction in
maps).
2. How do sinkholes form from Karst
topographies?
Sinkholes form when the ground on top
of Karst topographies (caves) collapses.
sinkhole
Ground on top collapses
Karst topography
Cave formation
http://www.youtube.com/watch?v=HYV6gBssMFs
Sinkholes in Florida
http://www.youtube.com/watch?v=67Y0pz9R32g
Cause of Florida sinkhole tragedy: Human activity or revenge of
the karst?
One of the most heavily
developed states is also one of
the most geologically hazardous
– two facts that are not mutually
exclusive in creating dangerous
sinkholes.
By Patrik Jonsson, Staff writer /
March 2, 2013
The Great Guatemalan Sinkhole
On Sunday, May 30, 2010, an enormous hole, 60 feet wide and 30 stories deep, opened
up in the middle of Guatemala City, swallowing a three-story building, a home, and at
least 100 people. Generally, sinkholes are caused by underground rivers or stores of
water which erode bedrock and cause the ground above to collapse. Guatemala City is
largely built on weak materials such as volcano pumice, however, and as such its
sinkholes open extraordinarily quickly, leaving little time for escape.
3. How do Freezing and Thawing ( frost wedging)
break rocks?
Mechanical weathering
Water expands by 9% when it freezes and
freezing and thawing wedges the rock
until it breaks.
1. Water fills a crack in a
rock.
2.The water freezes and the
pressure as the ice expands
makes the crack become
wider.
3. As this process is
repeated, the rock
eventually breaks into
several pieces.
Mountains shrink because of weathering and erosion.
http://www.youtube.com/watch?v=_XnCTcjNpuc
4. How do glaciation carve land?
U-shaped valley
Ablation is removal of material from
the surface
Abrasion is the mechanical scraping of
a rock surface by friction between
rocks.
Plucking or pulling off rocks.
Accumulation or gathering into a
heap mass.
Glacial erosion carves the land.
http://www.youtube.com/watch?v=XOGbOOaPHsw
5. What is an Avalanche?
High
slope
Gravity
mass of snow, ice, and rocks falling rapidly
down a mountainside( mass movement).
6. Running water causes ___.
Rill erosion
Gully
Erosion
Rill erosion is the removal
of soil by concentrated water
running through little streamlets,
or headcuts.
Gully erosion is the removal of
soil along drainage lines by surface water
runoff. Once started, gullies will continue
to move by headward erosion or by
slumping of the side walls unless steps are
taken to stabilise the disturbance.
7. What is Soil creep?
Fence is
NO longer
straight!
Low
slope
Gravity
Creep is the slow downward progression of rock
and soil down a low grade slope.
8. What is slumping
Slumping –is the movement of loose rock
and soil that moves a short distance down a
slope. It is usually shaped like a spoon.
9. What is a Rockslide?
High
slope
Gravity
Rockslide is a type of landslide where rocks
tumble downhill loosening other rocks on its way
and smashing everything in its path.
10. What is Deflation(Wind Erosion)?
Deflation- erosion of land by wind; can
lower the land's surface by several meters
11. What is foliation?
Foliation is a
weathering process that
causes rock layers to
peel away due to heat,
water, and wind.
12. What is graded bedding?
At the bottom of a river,
graded bedding is the
way sediment settles.
Large pieces on the
bottom, medium sized
pieces next, and then
the smallest particles on
the top.
Sedimentation is the settling of sediments
13. How does a V-shaped Valley form?
A river valley is
created when a
river carves into
mountains.
Water is the greatest
agent of erosion.
14. How does a U-Shaped Valley form?
U-shaped valleys
made when
glaciers scraped
through land areas.
Glacier is slowly
moving ice due to
gravity.
15. How can wind be a mechanical
agent of weathering?
Wind-blown sand
or other particles
chip away tiny bits
of rock from the
surface of exposed
rock. This leaves
rock with unusual
shapes.
16. What is root wedging?
Root grows in cracks and wedges
until the rock breaks.
17. How do lichens breaks rocks?
These are living
things known as
lichens that
cause chemical
weathering by
releasing weak
acid (carbonic
acid).
18. What are lichens
( biological weathering)?
http://www.youtube.com/watch?v=Te4qnLkHnS4
Lichens are composite
organisms consisting of a
fungus and a
photosynthetic partner
growing together in a
symbiotic relationship.
19. What are barrier islands?
Barrier Island of
North Carolina
Barrier Island is a narrow island of sand that
lies parallel to a shoreline.
20. Why are barrier islands
important?
Barrier islands protect the coastlines from
erosion and severe storm surge and
they harbor several habitats that are refuges
for wildlife.
avalanche
glaciation
lahar (volcano)
Snow ( fast)
Ice (slow)
Erosion
by
gravity
Soil creep
Rock slide
Rocks ( fast)
Soil (slow)
Use Venn diagram to compare glaciation,
avalanche, soil creep, rock slide and lahar.