Mason Invitational Test Flashcards
What is a glacier?
Accumulated mass of ice and snow
Glaciers are important indicators of climate change and play a significant role in Earth’s hydrology.
What percentage of Earth’s surface do glaciers cover?
5%
This percentage is significant in relation to global sea levels and climate patterns.
What is the largest ice sheet on Earth?
Antarctic Ice Sheet
The Antarctic Ice Sheet contains about 60% of the world’s fresh water.
What is the second largest ice sheet on Earth?
Greenland Ice Sheet
The Greenland Ice Sheet is critical for understanding sea level rise.
What is the crystal structure of ice?
Hexagonal
This structure is responsible for many of ice’s unique properties.
At higher altitudes, what process is overwhelming in loss of glacial mass?
Sublimation
Melting is influenced by temperature increases due to climate change.
In which one of the following countries are glaciers NOT found?
Australia
Australia lacks significant glacial formations compared to other continents.
Why are glaciers and ice sheets of such importance regarding global warming?
Warmer temperatures lead to melting, which adds water to the ocean and increases sea level
Melting glaciers contribute to rising sea levels, impacting coastal communities.
True/False: In an ice core taken from a glacier, the percent of volume of air of samples taken from top to bottom in the ice core decreases.
True
This indicates that older ice cores have less trapped air as they are denser.
What is the name for the end of a glacier?
Terminus, toe, or snout
The terminus is crucial for understanding glacier dynamics.
Rank the density of the following from 1-4, where 1 is the lowest and 4 is the highest: seawater, ice, freshwater, water vapor.
Water Vapor, Ice, Freshwater, Seawater
This ranking reflects the relative densities of these substances.
What are the two main types of glaciers?
Alpine (valley) and continental (ice sheet)
These types differ significantly in size and location.
List four KEY differences between alpine and continental glaciers.
- Size: continental glaciers cover large land areas while alpine glaciers are smaller & confined to valleys
- Location: continental glaciers are only found in Greenland & Antarctica while alpine glaciers are found in valleys across the world
- Impact of surrounding terrain: continental glaciers are not influenced by surrounding terrain while alpine glaciers are
- Impact on land: continental glaciers flatten landscapes over time while alpine glaciers carve U-shaped/V-shaped valleys
Understanding these differences helps in studying their effects on the environment.
What glacial feature is shown below?
Moulin
A moulin is a vertical shaft in a glacier that channels water to the base.
How does a moulin form?
Summer meltwater erodes ice
This process is essential for glacier dynamics and water flow.
The movement of a glacier is primarily driven by?
Gravity acting on the glacier’s mass
Gravity is the fundamental force behind glacier flow.
What is the primary function of regelation?
It allows ice to refreeze and exert pressure on bedrock, improving erosion
Regelation is a key process in the erosion and movement of glaciers.
How does continental drift influence glaciation?
- 1Altering air and ocean current circulation patterns
- block or redirect warm water currents
- change distribution of heat and potentially leading to cooler climates and glaciation.
Changes in current patterns can lead to cooler climates and glaciation.
Describe the transition from snow to glacial ice.
When snow falls, it piles up and gets squished into a type of snow called névé, which is made up of tiny particles that aren’t very tightly packed. Over time, as more snow falls and presses down, the névé gets even more compressed and turns into firn—a denser form of ice with small gaps in it. If this firn continues to be pressed and compacted, it eventually turns into solid glacial ice, where the ice crystals have merged together tightly.
This transition is critical for understanding glacier formation and behavior.
Describe the positive feedback loop involved in the growth of ice sheets during glacial periods.
When glaciation starts, the ice has a very bright surface that bounces sunlight back into space instead of letting it warm the Earth. Because the Earth stays cooler, even more ice can form and spread. As the ice grows, it reflects even more sunlight, which keeps the Earth cool and allows more ice to form. This cycle continues until something happens to warm the planet up and break the loop.
This feedback loop is vital for understanding past glacial periods.
What is the approximate weight of a 1 cubic-meter chunk of ice from a glacier?
Mass=Density×Volume
Between 800-1000 kg
The density of ice is approximately 0.9 kg/L. Since the volume is 1 cubic meter, you multiply:
920 kg/m 3X1m23 = 920kg
How many Kcal is needed to heat a chunk of ice by 1 degree Celsius near freezing?
Energy=mass×specificheat
450 Kcal
This is relevant for understanding the energy dynamics in glacial environments.
What is the term for the energy absorbed during the melting of ice?
Latent heat
Latent heat plays a crucial role in phase changes of water.
What is the term generally used for the geohistorical hypothesis that Earth has been fully covered in ice sheets?
Snowball Earth
This hypothesis explains significant climate changes in Earth’s history.
What process affects the changes in the amount of energy received on Earth, thus beginning and ending glacial periods?
Milankovitch cycles
These cycles relate to variations in Earth’s orbit and axial tilt.
How many years did the last glacial period last?
100,000 years
This period significantly shaped current Earth systems.
What is the name of the interglacial period the Earth is currently in?
Holocene
The Holocene has been marked by human civilization development.
What are the largest glacial lakes in the world?
Great Lakes
The Great Lakes are crucial for ecology and human activity.
What is the difference between an ice sheet and an ice cap?
Ice sheet: >50,000 square kilometers; Ice cap: <50,000 square kilometers
This distinction is important for glaciology studies.
How did the Late Paleozoic Icehouse/Ice Age influence modern-day Earth’s biodiversity?
Mass extinction of land animals, rapid warming of the Earth after this period, and massive decrease in atmospheric CO2
These events shaped the evolution of current ecosystems.
True/False: A period of time within an ice age characterized by a warmer climate and the retreat of glaciers is called an interglacial period.
True
Interglacial periods are essential for understanding climate cycles.
What is the glacial inversion method?
Conceptual process used to determine ice sheet evolution through time using landforms exposed on the beds of former ice sheets
This method helps in predicting future ice sheet responses.
What does it mean to have a stable isotope?
The nucleus of the atom does not break apart
Stable isotopes are essential in climate studies.
What are the two stable isotopes of hydrogen and their names?
H-1, H-2, protium, deuterium
These isotopes are used in various scientific analyses.
Which three of the following are stable isotopes of oxygen?
Oxygen-16, Oxygen-17, Oxygen-18
These isotopes are critical for paleoclimate reconstruction.
Using inferences, what isotope of hydrogen would be tested for?
H-2 or deuterium
Deuterium is often analyzed in climate studies.
Using inferences, what isotope of oxygen would be tested for?
O-18
O-18 is heavier and thus more likely to be analyzed in evaporation studies.
What can be inferred about the level of A-isotope in the sample of ice?
The A-isotope level is high too
This inference is based on the global meteoric water line.
What can you infer about the climate of the time of the ice sample being formed compared to modern climate?
Cooler and wetter climate
This inference is supported by isotopic analysis.
True/False: Scientists do not consider this to be a solid piece of evidence when it comes to analyzing past climate.
False
Ice cores provide valuable records of past climates.
If a virus is found within ice/permafrost, why would this be of concern?
DNA or itself could have survived, thus meaning that this virus could spread
This raises concerns about potential public health risks.
Is carbon dating (with Carbon-14) considered stable isotope testing? Why or why not?
No, C-14 is radioactive
Stable isotopes do not undergo radioactive decay.
If the law of superposition from sedimentary rocks is applied to ice, would the lower sections of an ice core be older or younger than the upper sections?
Older
This principle is crucial for dating ice cores.
What is a fjord?
A trough cut by glaciers
Fjords are important geographical features influenced by glaciation.
What is an ice shelf?
A non-broken chunk of ice (differing from icebergs)
Ice shelves play a critical role in stabilizing glaciers.
What is calving?
Large chunks breaking off of the edge of a glacier
Calving contributes to sea level rise.
What is the lithosphere?
Crust and upper mantle
The lithosphere is important for understanding geological processes.
What is a cirque?
Amphitheater/bowl cut by a glacier
Cirques are often the starting points of alpine glaciers.
What is a seismograph?
An instrument that measures details of events such as earthquakes
Seismographs are essential for studying tectonic activity.
What is firn?
Ice packed between snow and glacial ice
Firn is a transitional stage in the formation of glacial ice.
What is isostatic rebound?
The “bouncing back” of land after the pressure of a glacier on top is relieved
This process can affect local topography.
What is drumlins?
Remnant elongated hills from glacial movement.
What is Tor?
Large rock outcrop left behind by glaciers
What is a kettle?
Depression or hole formed by retreating glaciers
Kettles can form unique ecosystems.
What is a pro-glacial lake?
Meltwater trapped/dammed during glacial retreat
Pro-glacial lakes can significantly influence local hydrology.
What is precipitation?
Any form of water that comes down from the sky
Precipitation is a key component of the water cycle.
What is a moraine?
Rock and sediment mass carried down and deposited by a glacier
Moraines mark the former positions of glaciers.
What is permafrost?
Land that stays frozen for at least 2 years
Permafrost affects ecosystems and human infrastructure in cold regions.
What is groundwater?
Water buried below the surface
Groundwater is a crucial resource for drinking and irrigation.
What type of glacier is labeled 1?
1 -Ice field glacier
Ice field glaciers are extensive and can feed multiple outlet glaciers.
What type of glacier is labeled 2?
2 - Cirque glacier
Cirque glaciers form in mountainous regions and are often smaller.
What type of glacier is labeled 3?
3 - Valley glacier
Valley glaciers flow down valleys and are typically larger than cirque glaciers.
What type of glacier is labeled 4?
Piedmont glacier
Piedmont glaciers form where valley glaciers spread out onto a lowland.
What type of glacier is labeled 5?
Tidewater glacier
Tidewater glaciers terminate in the ocean and often calve to form icebergs.
What is the etymology of the glacier labeled 4 - and region in the US named after it?
Piemonte - Italian ‘foothill’
Region is east of the Appalachians
This term reflects the glacier’s formation in foothill regions.
Identify Landforms/occurrences
ice apron
Ice aprons are often found at the base of steep slopes.
Identify Landforms/occurrences
Ogives -
A wave-like feature on a glacier
Ogives indicate variations in ice flow and accumulation.
Identify Landforms/occurrences
Glacier Flour -
Finely ground rock flour produced by glacial erosion
Glacier flour can affect water quality in glacial rivers.
Who bestowed the name ‘Malaspina Plateau’ to the Malaspina Glacier?
W.H. Dall
Dall’s naming reflects historical exploration of glacial regions.
How to differentiate between tabular and non-tabular icebergs?
Tabular icebergs have flat tops, while non-tabular icebergs are irregularly shaped
This distinction is important for navigation and understanding iceberg dynamics.
What is an ogive?
A graphical representation of data in the form of cumulative frequency distribution
Often used in statistics to show the number of observations below a particular value.
What is glacier flour?
Finely ground rock produced by the grinding action of glaciers
It is often found in glacial meltwater and can give lakes a distinctive cloudy appearance.
Who bestowed the name ‘Malaspina Plateau’ to the Malaspina Glacier in 1874?
W.H. Dall
He did not understand the actual value of the landmark.
What are the two basic types of icebergs? and how would you tell the difference between them?
Tabular and non-tabular
Tabular icebergs are flat-topped and larger, while non-tabular icebergs are irregularly shaped.
Tabular icebergs are flat-topped and larger, while non-tabular icebergs are irregularly shaped.
Prior to what year were icebergs not monitored in the ocean?
1914
Define isostatic rebound in simple terms.
The land is able to spring back after the weight of the glacier is no longer on it
What does isostatic depression describe?
Pressure from the weight of glaciers/ice leaving dents in the Earth’s crust
What is Hooke’s Law?
An empirical law stating that the force needed to extend a spring increases proportionally with the displacement from equilibrium
What percent more will the first glacier depress the land than the second if the first weighs 45 million metric tonnes covering 3,000 square kilometers and the second 30 million metric tonnes covering 2,500 square kilometers- show your work?
25%
Weight per Area = Weight / Area Glacier 1 - Glacier 2 then difference / 2nd glacier area * 100%
Another Glacier, with weight of 16 million metric tonnes, What is the gradient of a glacier that starts at an elevation of 4 kilometers and goes down to sea level over a distance of 30 kilometers. What is the gradient of the glacier to the nearest tenth.
13.3%
Gradient = Veritical drop / Horizontal Distrance
This glacier presses down about 30 million metric tonnes of land about 30 meters. What is the force in mega newtons of which this land springs back if the glacier on top of it disappears and the land accelerates at about 0.00001m/s (hint: use Fnet = M x A? Show your work.
1metrictonne=1,000kg
30 MN
What is the names for lines that denote changes in elevation on a map for a specified increments?
Contour Line - Lines that denote changes in elevation on a map of specified increments
Which government agency has set the majority of topographic map symbols for the U.S.?
USGS
About how many miles did the furthest point of Hubbard Glacier extend into Yakutat Bay 700-1,000 years ago?
30-40ish miles
Why do glaciers adjust their overall size (advance and retreat)? and when do they?
To reach a balance between ice gained and lost. They advance when the glacier is gaining more ice than lost. Retreat when the glacier is losing more than lost.
What can be assumed about the average snowfall of the region compared to the loss of ice between 700-300 years ago?
Less snowfall than ice loss
What is the general mechanism for glacier mass loss?
Melting or calving of iceberges
Calving of icebergs is also a significant reason.
Why might Sih only see around 8 meters down a 20-meter deep hole he drilled?
The top of a glacier moves faster due to compression of the lower layers
What is a Milankovitch cycle?
A hypothesis about the long-term effects of changes in the Earth’s distance from the sun and its hand in triggering glacial periods.
Define eccentricity.
Shape of Earth’s orbit
Define obliquity.
Earth’s axis’ tilt in respect to Earth’s orbital plane
Define precession.
Direction of Earth’s axis of rotation
What are the minimum and maximum values of eccentricity that the Earth has?
0.0034 and 0.058
What are the minimum and maximum values of obliquity that the Earth has?
22.1 and 24.5 degrees
Around how many years is an eccentricity change cycle?
100,000 Years
Around how many years is an obliquity change cycle?
41,000 years
Around how many years is a precession change cycle?
26,000 years
In what year was Milankovitch’s work finally taken seriously?
1958
Around 800,000 years ago, the cycle of Ice Ages began to correspond to which Milankovitch cycle?
Eccentricity
What portion of the Earth experiences the largest variation in solar radiation?
Mid-latitudes/30-60 degrees north and south of the equator
What is the term for the amount of solar radiation received in an area?
insolation
What is a crevasse?
Deep, open crack of a glacier
What is a bergschrund crevasse?
A crevasse formed between moving glacier ice and the stagnant ice/firn above
Who named the bergschrund crevasse and when?
J.D. Forbes in 1843
What is a A ?
medial moraine - A ridge of debris formed where two glaciers meet
What is B?
lateral moraine - A ridge of debris along the side of a glacier
What is C?
recessial moraine - A moraine formed from material left behind as a glacier retreats
What is D?
ground moraine - A layer of debris deposited beneath a glacier
What is E?
terminal moraine - A ridge of debris deposited at the furthest advance of a glacier
What is an example of a radar satellite used to detect crevasses?
TerraSAR-X
Why might crevasses be dangerous?
Massive chasms; can be hidden beneath snow; snow bridges above can collapse
Outline a procedure that Shih and team can use to make sure no one is a victim to a crevass
Lenient Grading -know the process
A glacier erodes the underlying rock at a rate of 0.5 meters/year. The erodibility constant (K) for the underlying rock is 0.125 m/year * m. Using this information, calculate the velocity of the glacier
E=KV^2
(.5)=.0125*V^2
V=2 m/year
Calculate the basal shear stress of a glacier with a density of 917 kg/m^3, thickness of 10,000 meters, and slope of 25 degrees.
τb = ρ⋅g⋅h⋅sin(θ)
τb = (917)(9.81)(100)(sin 25)
τb =38,017,767 Pa (Pascals)
- A glacier receives mass through various forms of precipitation and loses mass through melting and sublimation. Over a one-year period, the glacier experiences the following rates of accumulation and ablation:
● Snowfall: 2.5m/year (in ice-equivalent depth)
● Rainfall: 1.0m/year (in ice-equivalent depth, assume immediately that it freezes upon contact with the glacier)
● Hail: 0.3m/year (in ice-equivalent depth)
However, the glacier also loses mass through the following processes:
● Ice melt: 1.8 m/year
● Sublimation: 0.5 m/year
a) Calculate the net mass balance of the glacier over this one-year period. What does this indicate about this glacier?
Total accumulation rate [1]:
Accumulation = 2.5 + 1.0 + 0.3 = 3.8 m/year
Total ablation rate [1]:
Ablation = 1.8 + 0.5 = 2.3 m/year
Net mass balance [1]:
Net Mass Balance = Accumulation −Ablation = 3.8 − 2.3 = 1.5m/year
This means the glacier is growing
Identify the type of glacier & How do you know?
Cirque glacier - located in a bowl-shaped depression at a high elevation.
List two regions where cirque glaciers can be found.
- Alps
- Rockies
- Andes
*Himalayas
What erosional and/or depositional landforms are created by cirque glaciers?
- Arêtes
- Moraines
*Horns
*Glaciail Troughs
Identify the type of glacier & How do you know?
Piedmont glacier - that is broad and lobe-shaped, spreading out onto a lowland.
List two regions where piedmont glaciers can be found.
- Alaska
- Patagonia
- Candian Rockies
*Himalayas
What erosional and/or depositional landforms are created by piedmont glaciers?
- Moraines
- Outwash plains
*Drumlins
*kettles
Identify the type of glacier and how do you know?
Rock glacier - mantled with a thick layer of debris and rock.
List two regions where rock glaciers can be found.
- Rockies
- European Alps
*Andes
What erosional and/or depositional landforms are created by rock glaciers?
- Moraines
- U-shaped valleys
Which method uses radar to measure the thickness and internal structure of glaciers?
Ground Penetrating Radar (GPR)
Which tool is primarily used to study the surface topography of glaciers?
LiDAR (Light Detection and Ranging)
Which remote sensing technique is most effective for assessing surface temperature variations on glaciers?
Thermal Infrared Imaging
