Geology 100 Final Exam
Study Topics
Below is a list of new topics that may be covered on the Final Exam. You should use this
list to evaluate your level of understanding. After studying, go through this list to (1)
insure you studied all the possible new exam topics; and (2) be sure you can say
something meaningful about each.
New material not yet covered on an exam:
I. Groundwater - Groundwater accounts for 22% of all fresh water and 98% of all liquid
Freshwater (Whatever part of this we complete on Wednesday).
A. Occurrence of Groundwater - Most groundwater exists in pore space between grains
and in fractures
1. Groundwater resided in pore space or fractures in rocks and sediments
2. Common misconception- Groundwater flows in underground streams. This is only
true Karst systems
3. Definitions: Aquifer, Aquiclude, Watertable (Peziometric surface).
- unconfined vs. confined aquifers
B. Interaction with surface
1. Recharge to groundwater system where aquifer gains surface water
2. Discharge from groundwater system to springs where aquifer looses water to
surface
- interesting example of geysers
C. Groundwater Flow
1. Parameters controlling flow: Porosity, Permeability and Hydraulic Gradient
2. Darcy’s Law (V=kdH/dL) describes the rate of flow
D. Groundwater Usage and Hazards
1. Extraction of groundwater can cause draw down the water table, causing (a) wells
to go dry; or (b) change the direction of groundwater flow, possibly contaminating a
well.
2. Subsidence of the ground surface from extraction of groundwater
3. Regional Drawdown = over use of non-renewable resource
II. Water and its amazing properties
A. Origin of water in and on the Earth
1. Water added during formation of Earth by accretion of planetesimals
2. Water added after formation of Earth by impacts of meteorites and comets.
3. Water released from the mantle to the surface reservoirs when plate tectonics began
to operate (~4.2 billion years ago). At this time the upper mantle began to melt and
produce the crust. This is when the mantle also began to transfer the water (from 1
and 2 above) to Earth’s surface.
4. Why does Earth have oceans and not the other planets?
B. Properties of Water
1. Water is a polar molecule!
a. Water molecule is bent (looks like Mickey Mouse – two hydrogen’s = Mickey’s
ears, big oxygen = Mickey’s head)
b. Hydrogen nuclei make the positive end and the electron cloud surrounding the
large oxygen is the negative end (i.e. a polar molecule)
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Geology 100 Final Exam
Study Topics
c. Polar nature of water allows the molecules to form hydrogen bonds - This gives
water all its remarkable properties
2. Remarkable properties of water:
a. High Surface tension
b. Density variations: Water vs. Ice
c. Heat Capacity of water is higher than all substances you are familiar with.
i. Thus, water can store and transport vast quantities of heat.
ii. So, ocean circulation controls climate
d. Latent Heat of Vaporization & Fusion are also very high
i. LH Vaporization powers atmospheric circulation (condensation releases E to
atmosphere) – recall that 70% of atmospheric heating results from this.
ii. LH Fusion regulates heat budget of oceans during formation and melting of sea
ice
C. Hydrologic Cycles:
1. Hydro tectonic Cycle = transfer of water between tectosphere (lithosphereasthenosphere) and the hydrosphere (exogenic reservoirs –oceans, atmosphere, etc.)
- Powered by Earth’s internal heat
2. Hydrologic Cycle = transfer of water between earth’s surface reservoirs of the
hydrosphere.
- Powered by solar energy
3. Water Distribution in exogenic reservoirs
a. Oceans = 97% of Earth’s water, covering 70% of Earth’s surface
b. Freshwater = 3% of all water
i. 77% of freshwater in Glaciers
ii. 22% of freshwater in Groundwater
iii. 1% of freshwater in Surface Water & Atmosphere
- 0.33% of freshwater in streams & lakes
III. Glaciers
A. Two Types of Glaciers
B. How Glaciers Move
1. Plastic flow
2. Basal Slip
3. Flow of glacier is combination of (1) & (2)
4. Advance or retreat of glaciers is dependent on the glacial budget (relative amounts
of accumulation versus wastage)
C. How glaciers erode, & transport sediment
1. Erosion by Plucking & Abrasion
2. Sediment is transported in the ice as it flows and slips down slope
D. Glacial deposits
1. Sediments are deposited from the glacier at the terminus and sides of the glacier as
the ice melts. These sediments are mostly in moraines (lateral, terminal, recessional
or ground moraines)
2. Glacial deposits bury underlying bedrock/topography leaving gently rolling
topography.
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Geology 100 Final Exam
Study Topics
IV. Ice ages = times of global cold temp and advance of glaciers to low latitude
A. Current Ice Age began ~2 m.y. ago (with a cooling event in the Pleistocene)
1. ~20 cycles between interglacial warm periods and glacial maxima
2. There have been many ice ages throughout Earth’s history
B. Effects of ice ages
1. Changes in sea level
2. Mass Extinctions
3. Transport and deposition of huge quantities of sediment
C. Causes of ice ages
1. Plate Tectonics
a. Place continents at poles where continental ice sheets can grow
b. Continents can disrupt ocean circulation, cooling higher latitudes
c. Ice-house effect (Himalayan uplift) – enhanced weathering consumes CO2
d. Albedo effect: Ice sheets reflect solar energy back out of atmosphere, cooling
Earth.
2. Milankovitch Cycles
a. Cycles in ‘perturbations’ of Earth’s orbit & axis
b. When they are ‘in phase’ the act in concert to warm or cool the Earth.
3. Volcanic Eruptions do not cause ice ages
V. Climate Change
A. Global Warming = world wide increase in average Temperature
B. Greenhouse Effect
1. Cause – what is it/how does it work?
2. Observed increase in CO2 and Methane over the past century correlates with
increasing global temperature indicating that today’s current Global Warming is
almost certainly caused by anthropogenic forcing of the greenhouse effect.
a. Observed effects: Increasing temperatures, receding glaciers and ice caps, rapid
rise in global sea level
b. Expected consequences of climate change: Extreme weather events (hurricanes,
winter and summer storms etc.), Shift in climate zones, loss of shoreline and
oceanic islands, continuation of Observed Effects (a)
3. Climate change will result in economic losses by 2010
B. Public perception of Climate Change issue
1. Concern about climate change is less than other environmental issues, and like
other issues the concern is waning
2. Common Misconceptions about climate change
a. Global Warming/Climate Change is not a current problem – Wrong, it is
happening today!
b. Scientists do not agree on the problem, its cause or existence – Wrong, all
credible scientists do agree that climate change is occurring in response to
anthropogenic forcing of the greenhouse effect.
C. Mitigation methods or how we might fix the problem - Decrease greenhouse gas
concentrations in atmosphere by…
1. Reduce anthropogenic production/emission of GH gasses
2. Sequester CO2 in ground (injection) or consume CO2 from atmosphere
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Geology 100 Final Exam
Study Topics
D. Ozone Depletion
1. Ozone occurs naturally in the stratosphere
2. Ozone in the stratosphere blocks harmful UV-B radiation
3. Cause of Ozone depletion = Manmade Chlorofluorocarbons (CFCs) degrade Ozone
4. Effect of O3 depletion
a. Increased numbers of skin cancer cases and deaths from skin cancer
b. Plankton in southern oceans killed by increased UV-B radiation (~4%) = loss of
base of marine food chain.
Material covered on previous exams: Use the previously provided lists of study topics
(PDF links on compass) for a listing of material that may be covered on the final. You
should study your notes on these topics, and also look at the previous exams that are on
reserve in the geology library. These indicate some of the important topics that may be
covered on the final exam. I will not take questions directly from previous exams. So
don’t study the exams, rather study the topics covered on them using your notes and the
book.
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