Glacier Landform, 100-200 words, geology homework help

Description

Requirements are in the uploaded files. Pleases follow the requirements and write 100-200 words. Also, please use some terms in “ch17” pdf in the writing. 

3 attachmentsSlide 1 of 3attachment_1attachment_1attachment_2attachment_2attachment_3attachment_3

Unformatted Attachment Preview

Discovering Physical Geography
Third Edition
by Alan Arbogast
Chapter 17:
Glacial Geomorphology: Processes
and Landforms
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Learning Goals
• Describe how glaciers develop
• Discuss the different kinds of glaciers
• Compare and contrast the various erosional and
depositional glacial landforms.
• Explain the history of glaciation on Earth,
particularly the Pleistocene glaciations
• Describe the impact that ongoing climate change
is having on glaciers around the world. What is
the evidence for that change?
Development of a Glacier
• A glacier is a slowly moving mass of dense ice
formed by the gradual thickening, compaction,
and recrystallization of snow and water over time
• Develop in regions where heavy snows fall in
winter and then do not melt completely during
the subsequent summer
– Summer temperatures must be sufficiently cool
Glacial Geomorphology: Processes and
Landforms
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Development of a Glacier: The
Metamorphosis of Snow to Glacial Ice
• Snow accumulates annually
to slowly increase overall
thickness
• Layers gradually compact
and recrystallize while some
snow melts and refreezes
– the lowest deposits of snow
are transformed into a
compact, granular substance
called firn
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Development of a Glacier:
The Glacial Mass Budget
• Zone of accumulation is at the
top where additions of annual
snow exceed losses
• Zone of ablation is downslope
where temperatures are higher
and there is more annual
melting and evaporation
• Equilibrium line is somewhere in
between ablation and
accumulation
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Development of a Glacier:
Glacial Movement
• Glaciers flow under their own weight
– Result of internal deformation and the
interior of the glacier behaving like a
plastic
– Ice moves most quickly at the core
– The upper part of
ice is brittle and
breaks forming
crevasses that can
develop from the
surface to some
depth
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Types of Glaciers:
Glaciers in Mountainous Regions
• High mountainous environments have long
winters and short, cool summers
• Three kinds of mountain ice masses:
– Ice cap is a dome-shaped sheet of ice
– Ice field is more constrained by topography and forms
in large basins or on top of plateaus
– Alpine glaciers flow down high elevation valleys
• Ice caps and fields are sources for alpine glaciers
• Cirque is also a source, as a small bowl-like depression
on a mountain flank formed by erosion
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Types of Glaciers:
Glaciers in Mountainous Regions
• Valley glaciers occupy
landscapes originally carved
by streams
• A piedmont glacier extends
entirely out of a valley into
the lowland
• Tidewater glaciers terminate
at the ocean
– Calving occurs as large blocks
of ice break off into the
ocean where they become
icebergs
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Types of Glaciers:
Continental Glaciers
• A huge ice mass that
covers a large part of a
continent or large island,
also called ice sheets
• Largely found in
Greenland and Antarctica
– In both areas, the weight of
these ice sheets presses the
lithosphere down into
aesthenosphere, called
isostatic depression
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Glacial Landforms: Landforms
Made by Glacial Erosion
• Erosion by glaciers occurs mainly by abrasion
and plucking
• Glacial abrasion takes place because moving ice
contains particles of sand or rock fragments
frozen to the bottom of the ice
– Glacial striations are scratches that indicate the
direction of glacial movement
– Glacial grooves are particularly deep scratches and well
expressed
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Glacial Landforms: Landforms
Made by Glacial Erosion
• Glacial plucking happens when a glacier pulls
large rocks or boulders from the ground as it
moves
– These boulders get carried within the ice or are
frozen to the glacier bottom where they act as tools
for abrasion
– Glacial erratics are boulders that are dropped when a
glacier melts and retreats
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Glacial Landforms:
Landforms Made by Glacial Erosion
• A roche moutonnée is a rounded
bedrock hill with a gradual,
smooth slope on one side, where
the other side has a steep slope
and an irregular surface
• A tarn is a small lake that is left
after the ice in a cirque melts
• An arête is a thin, steep ridge with
serrated crests between cirques
• A horn is created from three or
more arêtes
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Glacial Landforms:
Landforms Made by Glacial Erosion
• A glacial trough is created when a
glacier modifies a preexisting Vshaped valley into a U-shaped one
• Trunk glaciers form the deepest
glacial troughs, and tributary
glaciers carve less deep troughs
• A hanging valley is produced at the
intersection of the tributary and
trunk valleys when the glaciers
fully recede
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Glacial Landforms:
Deposition of Glacial Drift
• Glacial drift is sediment deposited by a glacier,
and is found in two forms
• Glacial Till is one form that is deposited directly
by a glacier and contains many different particle
sizes, said to be an unsorted deposit
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Glacial Landforms:
Deposition of Glacial Drift
• A moraine is a deposition
glacial landform, which is
a winding poorly sorted
ridge at the front or side
of a glacier
• Moraine types:
– Lateral: edge of the glacier
– Medial: between glaciers
– Terminal: end of farthest
advance of ice
– Recessional: where ice
retreats
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Glacial Landforms:
Deposition of Glacial Drift
• Drumlin is deposited till
that was streamlined in
the direction of ice flow
• Glacial outwash is carried
and deposited by water
that flows out and
underneath the glacier as
it melts and is well sorted
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
History of Glaciation on Earth
• First major glacial period appears to have
occurred about 2.3 billion years ago as a
response to fluctuations in early atmosphere
• Best understood glacial periods are between
about 1.6 million to 10,000 years ago in the
Pleistocene Epoch
– Four major advances of glacial ice:
1.
2.
3.
4.
Nebraskan (1 million years ago)
Kansan (600,000 years ago)
Illinosian (300,000 years ago)
Wisconsin (35,000 to 10,000 years ago)
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
History of Glaciation on Earth
During each Pleistocene
advance ,thick continental
glaciers extended from the
Arctic
• Laurentide Ice Sheet in
eastern North America
• Cordilleran Ice Sheet in
western North America
• Due to Earth’s orbital
fluctuations
During the Pleistocene,
alpine and continental
glaciation covered 30% of
the Earth’s landmasses
Today is only over 11% of
landmasses
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Possible Human Impacts on Glaciers
• Glacial advance and retreat are
controlled by fluctuations in
the glacial mass budget
– Global temperatures influences
rates of accumulation or melting
• Glaciers have been generally
retreating since the Little Ice
Age of 1500–1850
– Attributed by many scientists to
human-induced global warming
Rapid melting has been
observed on the
Greenland ice sheet
© 2007, John Wiley and Sons, Inc.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Do this through Google Map by searching the “Franz Josef Glacier, New
Zealand” and by copying and pasting the exact latitude and longitude
below (expressed as decimal degrees) into the search box. Make sure that
you include the negative sign in the latitude. “Visit” and explore the
features from spatial images and posted photos:
􏰀 Franz Josef – Texture (-43.4808, 170.2022)
􏰀 Franz Josef – Ice Texture (-43.4734, 170.1946)
􏰀 Franz Josef – Crevasses (-43.4497, 170.1756)
􏰀 Franz Josef – Terminus (-43.4483, 170.1742)

 
 Write a paragraph to describe your New Zealand Glacier exploration
(virtual) journey. Use the terms and concepts you learned from Chapter 17
in your writing. Especially note the differences in glacier and Ice texture,
the crevasses, and features around where the glacier terminates. Insert
screen captures if they help your description (note that the screen
captures should only be restricted for exercises as a learning process; you
should not distribute or post these screen captures beyond the submitted
exercise, which would violate copyright). 
 Write 100 – 200 words.
An illustration using Google Map for the exercise
Do this through Google Map by searching the “Franz Josef Glacier, New
Zealand” and by copying and pasting the exact latitude and longitude
below (expressed as decimal degrees) into the search box. Make sure that
you include the negative sign in the latitude. “Visit” and explore the
features from spatial images and posted photos:
􏰀 Franz Josef – Texture (-43.4808, 170.2022)
􏰀 Franz Josef – Ice Texture (-43.4734, 170.1946)
􏰀 Franz Josef – Crevasses (-43.4497, 170.1756)
􏰀 Franz Josef – Terminus (-43.4483, 170.1742)

 
 Write a paragraph to describe your New Zealand Glacier exploration
(virtual) journey. Use the terms and concepts you learned from Chapter 17
in your writing. Especially note the differences in glacier and Ice texture,
the crevasses, and features around where the glacier terminates. Insert
screen captures if they help your description (note that the screen
captures should only be restricted for exercises as a learning process; you
should not distribute or post these screen captures beyond the submitted
exercise, which would violate copyright). 
 Write 100 – 200 words.
An illustration using Google Map for the exercise

Purchase answer to see full
attachment

User generated content is uploaded by users for the purposes of learning and should be used following Studypool’s honor code & terms of service.