Sample Environmental Events Log Entries Ocean Acidific.docx

Sample Environmental Events Log Entries
Ocean Acidification
This article from the Environmental News Network caught my
attention because I rarely hear
about the oceanic events beyond comments concerning the
ocean's temperature. The article
draws attention to the acidification of the ocean that occurs
when the waters absorb carbon
dioxide. In history, the ocean's pH balance changed with
pollutant CO2, but the rate and amount
of change was less than current increases. If the rate of
pollution continues, calcifiers already
struggling may go extinct as some species did in historically
when the chemical changes were
less dramatic. This item relates directly to what we covered in
Chapter 7.
Source: Winter, Allison. "Ocean Acidification Occurring at
Unprecedented rates".ENN. Sept.
25,2012 http://www.enn.com/ecosystems/article/45006!
Ocean Salinity and Climate Change
NASA is taking an expedition to the saltiest part of the North
Atlantic to study how the saltiness
of the ocean relates to climate change as a part of their Salinity
Processes in the Upper Ocean
Regional Study (SPURS). I find this interesting because
biologists already use pH as a
measurement of health for aquatic biomes, why not test salt-to-

water variation to view oceanic
changes? This voyage will increase knowledge of the
acceleration of the Earth's water cycle.
Oceanographers claim that the ocean records rainfall better than
landmasses and translates these
fluctuations in to salinity changes. Along with recording new
salinity levels, the researchers are
delving into the drivers of these changes. Hopefully, the results
of the SPURS expedition will
yield information that helps studies of other areas with major
salinity changes and how they will
affect the water cycle in surrounding areas. This topic relates
to material in Chapter 11.
Source: Cole, Steve. NASA - NASA Voyage Set To Explore
Link Between Sea Saltiness And
Climate. (n.d.). Retrieved October 6, 2012, from
http://www.nasa.gov/home/hqnews/2012/sep/HQ_12-
305_Ocean_Salinity_SPURS.html
Changes in Arctic Winds
According to a study by "scientists from Rutgers University in
New Jersey, the University of
Sheffield in the United Kingdom, and the Joint Institute for the
Study of the Atmosphere and
Ocean, a partnership of NOAA and the University of
Washington.", Arctic winds that normally
travel west to east circulating the cold air are now moving south
to north. This change further
warms the Arctic from the warmer air currents. Since 2007, the
air currents from the south are
increasing contributing the record ice loss this summer. The
article caught my eye because the
change in air currents and their immediate results of ice loss
will dramatically affect the Northern
hemisphere causing drastic climate changes. This topic relates

to what we covered in Chapter 5.
Source: Arctic summer wind shift could affect sea ice loss and
U.S./European weather, says
NOAA-led study. (n.d.). Retrieved October 14, 2012, from
http://www.noaanews.noaa.gov/stories2012/20121010_arcticwin
ds.html
Copyright © 2012 John Wiley & Sons, Inc. All rights reserved.
Chapter 14
Glacial and Periglacial Landforms
Visualizing Physical Geography
by Timothy Foresman & Alan Strahler
1
© 2012 John Wiley & Sons, Inc. All rights reserved.
Chapter Overview
Types of Glaciers
Glacial Processes
Glacial Landforms
Periglacial Processes and Landforms
Global Climate and Glaciation
2

Types of Glaciers
Cryosphere = Portion of the hydrosphere in which water is
stored as ice (70% of Earth’s fresh water)
Glacier = Any large natural accumulation of land ice affected
by present or past motion
3
Types of Glaciers
Two broad categories of glaciers are alpine and ice sheets (also
called continental glaciers)
Glaciers form in regions with low temperatures and sufficient
snowfall (high altitude or latitude)
4
Types of Glaciers
Alpine glaciers = A glacier formed at high elevation, typically
flowing down steep mountain slopes and filling valleys below
Cirque glacier
Valley glacier
Piedmont glacier
Tidewater glacier

5
Types of Glaciers--Mountains
Ice caps: continuous masses that cover mountaintops
Ice fields: interconnected valley glaciers and protruding ridges
or summits
6
Types of Glaciers
Ice sheet = A large, thick plate of glacial ice that moves
outward in all directions
Ice shelf: plates of glacial ice floating on sea
Pieces break off to become icebergs
7
Glacial Processes
Formation of Glaciers
Firn: granular ice formed by melt and refreeze

Zone of accumulation: where snow accumulates
Zone of ablation: more ice lost than formed
Equilibrium line: rate of snow accumulation = loss from
melting and evaporation
8
Glacial Processes
Glacier is open system that has dynamic balance between input
of accumulated snow and output of melting or evaporation
Input=output, called mass balance, changes each year due to
weather
Glacial monitoring
9
Glacial Processes
Monitoring the effect of climate change on glaciers
1. Melting glaciers are visually striking evidence of climate
change. List, in order, the steps that would lead to a glacier’s
retreat due to climate change.
2. How might the loss of the glacier’s ice volume affect
downstream ecosystems and human settlements?
McCall Glacier, Alaska, 1958 (left) and 2003 (right)

10
Glacial Processes--Movement
Large bodies of ice can move due to gravity
Pressure on ice at bottom changes physical properties of ice,
causing it to lose rigidity & become plastic
Basal sliding: layer of liquid water under glacier allows it to
move; pressure and friction
Crevasse: brittle surface layer cracks due to movement over
ridge or cliff
11
Insert Figure 14.5.
Glacial Processes
Glacial Erosion and Deposition
Glacial drift = General term for all varieties and forms of rock
debris deposited by ice sheets
Stratified drift: layers of sorted & stratified clays, silts, sands
and gravel
Till: unstratified mix of rock fragments
Moraine: depostional landform from glacier
Glacier deposits load at lower end where ice melts
12

Glacial Landforms
Glaciation = Single episode or time period in which ice sheets
and alpine glaciers formed, spread, and disappeared
13
Glacial Landforms
Maximum glaciation during the Ice Age; global sea level about
400 feet lower than it is today. Note Canadian and United
States’ ice coverage
14
Glacial Landforms
Landforms Made by Alpine Glaciers
Before glaciation
Snow accumulates
Glaciation
Melting glaciers
15

Glacial Landforms
Tarn: small lake
Horns: Peaks
Arêtes: Sharp ridges
Col: Notch
16
Glacial Landforms
Glacial trough = deep, steep-sided valley shaped by the action
of alpine glaciers.
Hanging valleys: floors of side tributaries lie above valley floor
of main glacier
17
Glacial Landforms
Fjord = Narrow, deep ocean inlet that partially fills a glacial

trough
Moraine: sediment deposited along front or side of glacier
Lateral moraine: ridge formed by rock waste that falls onto
glacier’s edges
Medial moraine: two glaciers meet and lateral moraines
combine
18
Glacial Landforms
Landforms Made by Ice Sheets
During glaciation
Delta
Braided streams
Outwash plain
After melting
Moraines
Eskers: sinuous ridge of sand & gravel
Drumlins: smooth, rounded oval hill
Kames: isolated mound or hill of sand and gravel
19
Glacial Landforms
Ice sheets are like huge conveyors that move and deposit debris
Formation of a moraine

Terminal moraine: deposit of debris, sand and gravel at front
edge of ice sheet
Recessional moraine: deposits formed as ice sheet retreats
20
Glacial Landforms
Till plain
Lodgement till: compacted by ice sheet
Melt-out till: top layer; looser
Esker: ridge of sand
Drumlin: rounded, oval hill of till
21
Glacial Landforms
Outwash plain
Kettle: depression formed as sand & gravel built up around
stagnant ice
Kame: hill or mound of sediment found on outwash plain

22
Glacial Landforms
Landforms Made by Glaciation—Human Development
Agriculture
Glaciation can have positive and negative effects
Glacial till in some areas is thin and very stony; makes
cultivation difficult
Flat till plains, outwash plains and lake plains can provide very
productive agricultural land
Stratified drift
Sources of raw materials (sand and gravel)
Good material for aquifers
23
Periglacial = An environment located in cold climates or near
the margins of alpine glaciers or large ice sheets.
Permafrost = Soil, regolith, and bedrock at a temperature that
remains below 0°C (32°F) on a perennial basis.
24

Permafrost processes
Active layer: shallow surface layer that thaws with changing
seasons
Taliks: pockets of unfrozen ground that occur in zone of
discontinuous permafrost or underneath a deep lake or river in
zone of continuous permafrost
Ground Ice: frozen water in pore spaces in ground
Gelifluction: Melting of ice in soil during warm periods causes
slumping to form terraces and lobes
Ice wedges: form from repeated freeze/thaw cycles
25
Ground Ice and Periglacial Landforms
Pingo: ice dome formed by drained lake
Patterned ground: freeze/thaw
26
Human Interactions with Periglacial Environments

Increased permafrost thaw causes problems for development
Frozen ground contains a lot of CO2 and methane
Thermokarst: water-filled depressions caused by melting
27
History of Glaciation
Deglaciation: ice melts at start of milder climate called
interglaciation
Interglaciation
Ice Age: period of millions of years of generally cold climates
consisting of alternating glaciations & deglaciations
28
History of Glaciation on Earth
The Ice Age: the Cenozoic Era has seen gradually cooling
climate; past 2.5 million yrs has seen the Late Cenozoic Ice Age
Last major glaciation started about 120,000 yrs ago (Wisconsin
Glaciation)
More ice coverage increased albedo, which caused more cooling
More water in form of ice, so sea level drops
The Holocene Epoch: period of interglaciation that started at
end of Wisconsin period

Rapid warming
Shifting of climate zones and plant coverage
Little Ice Age: from about 1350 to about 1850; not global
29
History of Glaciation
Triggering periods of glaciation
Continental drift
Changes in Earth/Sun geometry (the Astronomical Hypothesis)
Change in shape of orbit
Tilt angle of Earth’s axis changes
Changes in aphelion & perihelion with seasons
30
Changes in Earth-Sun geometry
When the tilt of the Earth is greatest (24.5°), what
happens to the intensity of the Earth’s seasons?
a. Summers are cooler and winters are warmer.
b. Summers are warmer and winters are cooler.
c. Summers are warmer and winters are warmer.
d. Summers are cooler and winters are cooler.

31
Cycles of Glaciation
Cycles in solar revolution and axial rotation mean that annual
insolation experienced at a latitude change yearly
Glacial onsets begin with cooler summers that allow snow to
accumulate
Albedo increase further cools
Milankovitch Cycle plots the change in insolation by year
32
Glaciation and Global Warming
Global temperatures increasing
Shrinking polar sea ice
Albedo changes and feedback loops
Changes in Arctic, Antarctica and Larsen’s Ice shelf
33
Glaciation and Global Warming

If polar sea ice shrinks as predicted by 2050, the zone of
continuous permafrost will____.
a. increase in area
b. decrease in area
c. move farther south
d. remain the same
34

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