Transcript Examples of Weathering, Erosion, and

Examples of
the Effects of
Weathering,
Erosion and
Deposition
on Ecoregions
of Texas
Images from Google Earth
http://www.canyongorge.org/
Watch a video on the site above.
This was on google earth. Can
search “how canyon lake gorge
was formed”.
Description: Canyon Lake Gorge
formed during a flood event in July
2002. Over 89 cm of rain fell in the
upper part of the Guadalupe River
Watershed in approximately one
week causing tremendous flooding.
Erosion in the Coastal Prairies and Marshes - Ecoregion 2
Erosion: The movement of weathered earth materials by moving water, wind, gravity
or ice
Ex: waves causing beach erosion (shoreline of Texas is disappearing) running water
Ex: sand storm wind
Ex: rain causing a mudslide running water and gravity
Ex: landslide gravity
Ex: rain carrying soil and gravel down a driveway running water and gravity
Sandy barrier islands are the most conspicuous
coastal feature of Texas. Barrier islands, such
as Mustang Island shown above are migrating
landward as the mainland shore retreats due to
relative sea level rise.
The development and maintenance of the barrier
islands involves a balance between sediment
supply, longshore currents, bottom topography,
and wave and tidal activity. Texas barrier islands
will likely continue to migrate landward as the
mainland shore retreats due to relative sea level
rise.
The southeasterly offshore winds also contribute
to this migration as gulf-facing sand is picked up
and deposited into back bays and on the
mainland.
Bolivar Peninsula: Oblique aerial photography of Bolivar Peninsula, TX, on
September 9, 2008 (top) and September 15, 2008, two days after landfall of
Hurricane Ike (bottom). Yellow arrows mark features that appear in each image. In
addition to the loss of houses, the evidence of inundation here includes eroded
dune face and sand deposited well inland of the shoreline.
Galveston Island and Beach Erosion
Aerial photo of Galveston, TX, on September 9, 2008 (top) and September 15, 2008, two days after landfall of
Hurricane Ike (bottom). Yellow arrows mark features that appear in each image. Hurricane-induced waves and surge
destroyed a small walkway. Coastal-change impacts include beach and dune erosion, and the removal of
considerable dune vegetation. This location is on the right-hand side of the hurricane track and likely experienced
the strongest winds, highest surge, and waves.
Rivers and Deposition
Deposition: The process of eroded
earth materials (sediments) being
deposited in a new location
Ex: delta-where sediment is deposited
where a river flows into an ocean or
lake builds up a landform
Ex: sand dune-a deposit of wind blown
sand
The marker on Google Earth is the
mouth of the Brazos flowing into the
ocean (see map on slide 2 of this ppt)
Eroded Sediment Deposit
Riverbed high resolution capture
taken at Brazos River, Texas, USA
Weathering and Palo Duro Canyon (High Plains Ecoregion)
Weathering is the breaking down and/or wearing away of earth materials (rocks) into smaller
pieces.--Must occur before erosion can happen
--No movement is involved
Sediments- naturally-occurring material that is broken down by processes of weathering;
small/tiny pieces of rock
Physical/Mechanical weathering-the breaking down of rocks into smaller pieces (wind, flowing
water, ice, gravity, animals/plants, temperature changes)