Transcript Weathering/Erosion/Deposition

Weathering/Erosion/Deposition
All roads lead to…
LANDFORMS!!
Let’s start with the foundation:
Various landscape features are the result of
several processes:
Weathering
Erosion
Deposition
Tectonics
Glaciation
Glaciation is primarily responsible for the
various Landscape regions of NYS.
But wait, there’s more . . .
The driving force behind weathering,
erosion and deposition is…
The WATER or HYDROLOGIC Cycle
The sun and gravity control this cycle.
So, let’s start from the beginning. . .
In the beginning, there was . . .
Water
And it was good.
The Water/Hydrologic Cycle
 Evaporation  Condensation  Precipitation 
Infiltration  Run-off
 Without these processes, weathering, erosion and
deposition could not occur.
So, now that we have a little
background, let’s get started!
Weathering
Weathering is the breakdown of rocks.
It occurs when rocks are exposed to
agents such as water and air.
These weathering agents can change the
physical and chemical properties of
rocks.
As rocks are broken down, they are
classified as sediments
Sediments can be: boulders, cobbles,
pebbles, sand, silt, clay and colloids
Remember this . . . ?
Types of weathering:
Physical/Mechanical:
Rocks are broken down into smaller
pieces without changing the integrity or
chemical composition of the rock.
Chemical:
Rocks are broken down and the chemical
composition of the rock is changed.
Physical Weathering:
Frost action/Ice
Wedging:
The breakup of
rock as the result of
the expansion and
contraction of
water.
Abrasion:
The wearing down of rock as they rub and
bounce against each other.
Common in stream beds, windy areas and
under glaciers.
Exfoliation:
The peeling away of surface sheets of rock.
Common with shale, slate and mica.
Chemical Weathering:
Oxidation: When
oxygen reacts with
minerals.
 Remember ~ minerals are the
building blocks of rocks and
are composed of elements
 i.e. When oxygen combines
with Iron (Fe), it forms iron
oxide, more commonly known
as . . . Rust!
Hydrolysis: When
water interacts with
minerals.
Hydro = water
Lysis = Break
Hornblende and
feldspar often
combine with water
to form clay
Carbonation: When
carbon dioxide
interacts with
minerals.
Causes the formation
of:
Stalactites (top)
Stalagmites (bottom)
Sink holes
Karst Topography
Weathering Rates:
The rate at which material is weathered
is dependent upon:
Particle size/surface area
(more surface area = more weathering)
Mineral Composition
(softer minerals = more weathering)
Climate
(warmer temperatures = more weathering)
A quick review . . .
The water/hydrologic cycle is chiefly
responsible for weathering, erosion and
deposition
Weathering is the breakdown of rock materials
by either . . .
Physical means: frost wedging, abrasion,
exfoliation or . . .
Chemical means: oxidation, hydrolysis and
carbonation.
The rate of weathering depends on size, climate
and mineral composition.