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1. Chapter 13

2. Glacier
-about 10% of the land
surface is covered by
glaciers.
- thick ice mass formed by
compaction and
recrystallization of snow.
- mostly found in polar
regions, some are found in
mountain ranges.
- 68% of the total fresh
water on Earth is locked up
in ice and glaciers.

3. Types of Glaciers
- can be classified in two
ways: by morphology and
by thermal characteristics.
Based on morphology &
Geographic location:
1. Alpine glaciers. Formed
on the crests and slopes of
mountains and are also
known as “mountain
glaciers”, “niche glaciers”,
or “cirque glaciers”. Valley
glacier is a type of alpine
glacier that fills a valley.

4. 2. Ice Cap. Also known as ice
field, is considered as large
glaciers that cover an entire
mountain, mountain range,
or volcano.
3. Continental glaciers. Also
known as ice caps,
considered as the largest
glacial bodies.
4. Tidewater glaciers. Are
glaciers that flow and reach
the sea forming icebergs.

5. Based on thermal
characteristics:
1. (Temperate. The
temperature at the
base of temperature
glacier maybe 0°C,
usually found at high
altitudes in
temperature
locations.
2. Polar. Polar glacier
has a temperature of
below 0°C throughout
its mass (from surface
to base).

6. Glacial Budget
- refers to the ratio between
ice gained and ice lost.
• Positive Budget. When
glacier gains more volume
during new snowfall than it
loses during melting
process.
• Negative Budget. When
ice lost is greater than ice
gained causing glacier to
recede.
• Balance. When ice gained
is equal to ice lost.

7. Glacial Movement
- there will be movement of
glacier when the
temperature at the base is
above the pressure melting
point.
Positive budget will move
faster than those with
negative budget.
Basal debris can speed up the
glacial movement, however,
it can also slow down the
movement of glaciers.
Glacier Surge. Is the rapid
movement of glacier.

8. -Plastic flow refers to the
movement of ice crystals within
the glaciers. These results to the
movement of glaciers as a whole.
There is no plastic flow in a depth
above 50meters.
-Upper zone is called the zone of
fracture.
-Upper layers are more brittle and
form deep cracks called
crevasses.
-Upper portion of glaciers where
accumulates faster is the zone of
accumulation.
-Lower portion of the glacier where
there is more melting of ice than
accumulation is called zone of
wastage.
-Irregular boundary between these
two zones is called the snow line.

9. Glacial Erosion
Two ways:
1. Plucking. Or quarrying
occurs when large
fragment of underlying
rock is being removed.
2. Abrasion. Occurs when
rock frozen on the base
and the back of the glacier
scrapes the bed rock.
3. Freeze thaw

10. Depositional Landforms:
*Small-scaled*
1. Rock flour. Fine-grained
material.
2. Glacial striations. Long
parallel scratches and
grooves.
3. Glacial polish. Smooth and
shiny surface produced on
rocks underneath a glacier
which is the result of fine
abrasion from the sediment
carried by a glacier.

11. *Larger-scale*
1. Cirque glacier. Is the
alpine glaciers that fill the
bowl-shaped, steep-walled
depressions carved out of
the side of mountains.
2. Tarn. When glacier melts,
it forms a small lake that
fills the central depression
in a cirque.
3. Arête. Steep-sided, sharp-
edged ridge.
4. Horn. High mountain
peak formed when the
walls of three or more
glacial cirques meet.

12. Landscape. Is form when
loose materials from one
area is deposited to
another area.
Glacial drift. Is the
sediment deposited as a
result of glacial erosion.
Erratic. Large boulder
that is glacially
deposited.
Till. Is the mixture of
finely crushed rock,
sand, pebbles, and
boulders deposited by
glacier.

13. Moraine. Is the
deposited till that
forms a ridge or
mound.
Lateral moraines. Is
the moraines that is
deposited along sides
of alpine glaciers.
Medial moraine. Is
the ridge that runs
down at the middle of
the new glacier.

14. Terminal or End
moraine. Is moraine
deposited at the edge of
a glacier.
Recessional moraine. Is
formed in a retreating
glacier which remained
stationary for sufficient
time to produce a
mound of material.
Ground moraine. Is a
continuous layer of till
deposited beneath a
steadily retreating
glacier.

15. Drumlin. Is tear-drop-shaped
hill formed underneath a
glacier.
Terminus or Glacier snout.
Is where the meltwater
emerges in large streams that
carry it away from the
glacier.
Outwash plain. The sediment
carried by the meltwater is
then deposited forming a
broad plain.

16. Eskers. Is the glacier that
melts and retreats that
form a long, twisting
ridges.
Kame. Is a conical mound
or hill that is formed
when the glacier melts
away.
Kettle. Is formed when a
large chunk of ice
separates from the main
glacier.

17. Glaciers of the past: Ice
age
- is a geological period
characterized by a long-
term decrease in the
temperature on the
Earth’s surface and
atmosphere.
- this causes the formation
of continental ice sheets,
polar ice sheets and
alpine glaciers.
Interglacials. Is the warm
period between long-term
ice ages.

18. Five stretches in geologic time that show evidence of
glaciation:
1. In the middle of Huronian era in Precambrian time.
2. At the end of the proterozoic era.
3. The middle of the paleozoic era between the Ordovician
and Silurian Periods.
4. The late Carboniferous and early Permian Periods in the
late Paleozoic era.
5. In the Pleistocene Epoch in the Quaternary Period.

20. Evidences of Ice Age
1. Geologic Evidence.
Includes glacial debris,
drumlins, valley cutting
and the deposition of till
such as valleys and
glacial lakes.
2. Chemical Evidence. Is
proven by examining
isotopes of sediment and
cores of glacial ice. The
time of ice ages is
determined by the use of
carbon dating.

21. 3. Paleontological Evidence. Consists of changes in the
geographical distribution of fossils of cold-adopted
animals.

22. Causes of Ice Age
According to astronomical
theories, the causes of ice
age are:
 Increased eccentricity of
the earth’s orbit
 Changes in the intensity
of solar radiation
 The earth passing
through cold regions of
space and ice dumped
directly from space.

23. Croll’s Theory. Explains
that the effect of moon
and sun on Earth causes a
periodic shift in the
position of perihelion.
However, this theory is
not confirmed by
geologic evidence.
Milankovitch theory.
Describes that the cause
of ice age is the combined
effect of changes in
Earth’s orbit-its shape,
the tilt of the earth’s axis
and the wobble of the
Earth’s axis.

24. Another cause of ice age:
Changes in atmospheric
composition. Which
includes the relative
amounts of water vapor,
carbon dioxide, methane,
sulfur dioxide, and
various other gases and
particulates in the
atmosphere.
Motion of Tectonic plates.
Ocean current
fluctuations.

25. Effects of Glaciation
 Freezing of plants and
animals.
 Migration of some species.
 Changes the biogeographic
distribution patterns of
marine and terrestrial
plants.
 Displacement of climatic
zones.
 Can affect to the volume,
variability, and water quality
of runoff in areas.
 Has an effect on topography.
 Flattening of landscape by
erosion and dumping of
debris from melting ice.
 Many of the earth’s modern
landforms were formed.