Paleo Exam 1
How many icehouse eras have existed since the Cambrian (or during the Phanerozoic)?
3
What parts of ice sheets gain and lose mass? Why?
50 meters and up of a glacier, the ice breaks in a brittle way, where as below 50 meters it breaks in a slow plastic flow way. If the ice is less than 30*F it behaves in a stiff way. The closer to freezing it is, the easier it breaks.
Water heated to 100 C will stop increasing in temperature for a time even as additional energy is applied. Why?
A significant amount of energy is required to affect the state change of water from liquid to vapor
What kind of radiation in trapped by greenhouse gases? What is the effect on Earth's climate
About 95% of long wave radiation is absorbed by greenhouse gases. The greenhouse gases trap the heat in our atmosphere. Whithout these gases, all heat would escape back into space. They keep our surface about 31*C warmer then it would be without them.
How does reflection of solar radiation from Earth's surface ass to the effects of uneven solar heating in creating a pole-to-equator heat imbalance?
Areas neat the equator receive more radiation because they have a more direct area to the radiation compared to the poles. Because of this, the equator is naturally warmer than the poles. Also the pole regions have a lot more snow and ice that reflects what little radiation they receive back into space. The equator has little to no snow or ice therefor more radiation is absorbed.
What regions of the ocean are most productive and why?
Areas with a lot of light and nutrients are most productive. The light and nutrients allow phyplankton to form which feeds larger organism. Both the Pacific and Atlantic oceans near the equator are very productive as well as the Southern Ocean around Antarctica and areas with upwelling zones.
A powerful volcanic eruption whose airborne particles lead to a reduction in solar energy for a period of six months would have what effect on the deep ocean? a. The deep ocean would respond with varying amplitude to the changes in solar energy. b. The deep ocean would change very little, as the response time of the deep ocean is too slow for it to show significant changes. c. The deep ocean would cool quickly, tracking the reduction of solar energy. d. There would be a highly dynamic response in the deep ocean to the reduction of solar energy.
B
A slow increase of the Sun's strength over millions of years would have what effect on land temperatures? a. The land temperatures would not change, not having enough time to react to the change in the Sun's energy. b. The land temperature would slowly increase, tracking the change in the Sun's energy. c. There would be a highly dynamic response in land temperatures to changing energy of the Sun. d. The land temperatures would respond with varying amplitude to the changes in the Sun's energy.
B
In which of the following depositional settings is the disturbance of sediment least likely over the long-term? a. the coastal margin in a storm-prone region b. the deep ocean floor c. the ocean floor at 50 meters water depth d. a lake in an active tectonic basin
B
The half-life of the radioactive isotope 14C decaying to the stable isotope 14N is 5,780 years. The analysis of a sample of organic material indicates that 25% of its original 14C is still present. The age of this sample is: a. Carbon-14 cannot be used on materials younger than 100 million years old. b. 11,560 years old c. 17,340 years old d. 5,780 years old
B
What effect does sea ice have on atmospheric temperature? a. Thermal energy is conducted rapidly through sea ice from the ocean to the atmosphere above. b. Sea ice prevents the release of heat from the ocean beneath, allowing air temperatures to get much colder in winter. c. Latent heat is given off to the atmosphere as sea ice melts, providing additional warming. d. Solar energy is reflected off sea ice and back through the atmosphere, providing additional warming in summer.
B
What is the average amount of solar energy retained by Earth? Please note that all units are given as watts per square meter. a. 340 W/m2 b. 238 W/m2 c. 1362 W/m2 d. 2700 W/m2
B
Which of the following statements about monsoonal circulations is correct? a. Monsoons are caused by tropical storms embedded in the Hadley cells. b. Summer monsoons tend to produce precipitation on continental surfaces. c. The strongest monsoon circulations occur where there are little seasonal differences in the surface heating of land and ocean. d. High pressure over continental surfaces leads to heavy precipitation on land.
B
Which of the following would be an appropriate archive for reconstructing what the climate was like 50 million years ago. a. instrumental records b. ocean sediment cores c. ice cores d. tree rings
B
Explain how paleomagnetism tells us about the past latitudes of conitients?
Basalts deposited on continents help us determine pst latitudes in relation to the magnetic poles. If the molten lava cools near the pole it will cool near vertical, as opposed to if it was new the equator and cooled closer to horizontal. Looking at these orientation tells us where continents use to be located.
What is the central concept behind the BLAG hypothesis?
Basically ti says that increased spreading rates lead to increased releases of carbon dioxide by volcanic degassing into the atmosphere.
In which of the following areas would you expect upwelling of ocean water to occur? a. where sea ice forms b. where surface waters cool c. where surface winds blow parallel to coastlines d. where high evaporation rates increase surface salinity
C
When an initial climate forcing triggers responses in the climate system that dampens the initial change, it is referred to as a(n)... a. equilibrium response b. positive feedback c. negative feedback d. enrichment factor
C
Which of the following is an example of a tectonic process? a. The changing amount of solar radiation by season. b. All of the answers are correct c. The opening and closing of ocean basins. d. the increasing strength of the Sun of the last 4.55 billion years.
C
Which two major types of biotic data are most important to climate reconstructions? a. insects and fish remains b. dinosaur fossils and corals c. microfossils of pollen and plankton d. petrified trees and corals
C
What different and opposing roles do clouds play in the climate system?
Clouds reflect some of the incoming long wave radiation, this cools the surface. Clouds also absorbs the heat given off by the Earth's surface and warms the surface even more.
Write a chemical reaction showing how weathering removes carbon dioxide from the atmosphere.
CaSiO3+CO2 --> CaCO3+SiO2 (silicate rock + atmosphere --> plankton + plankton)
How does climate forcing differ from climate response?
Climate forcing is the forces that cause a response. The four main types are tectonic processes, Earth-orbital changes, changes in the Sun's strength, and anthropogenic forces. Climate response is how the climate responds to those actions, typically by warming or cooling.
Change of each of the following causes external forcing to Earth's climate system except a. plate tectonics b. the Sun's strength c. Earth's orbit d. the atmosphere
D
When considered within the time scale of the last 1000 years, what is the present-day state of Earth's climate? a. Earth is in a moderate state and cooling b. none of the answers are correct c. Earth is in a relatively cold state d. Earth is in a relatively warm state
D
Why does the importance of different climate archives change for different time scales?
Different climate archives have different time scales, durations, and resolutions. Archives happen at different spans of time.
How does the method of dating climate records vary with the type of archive?
Different types of archives require different types of dating. For example, C14 dating wouldn't be useful when trying to date something millions of years old just as Uranium dating isn't useful to dare southing 10,000 years old. How old and they type of archive determines what method to use.
Anthropogenic burning of fossil fuels increases the rate of which of the following fluxes in Berner's Long Term Carbon Cycle?
Fwg- organic carbon weathering
Explain, in a general way, how climate change depends on the rate of application of climate forcing and the natural response time of the climate system.
If there is a slow change in climate forcing, the response time is fast and can easily keep up with the change in force. If the change in climate forcing is fast, and the response time is slow and delayed. In times when the climate forcing changes last longer, the response has more time to "catch up" to the change. If it is changing a lot, the response doesn't have as much time to "catch up".
Place the following in order of highest albedo to lowest albedo.
In Book- List out
Rank the following in order of fastest response time to slowest response time.
In Book- list out
Carbon Reservoir
In book- map out
What causes the monsoon circulation to reveres from summer to winter?
In summer the land in heated by strong solar radiation. The warm air rises and the cooler air from the ocean moves in through a low pressure zone. This creates cloud formation and precipitation. In winter the land produces less heat than the ocean and the air from the land sinks while the air from the ocean rises. This makes the clouds and perception fall on the ocean instead of the conitnent.
What factors explain why Earth is habitable today?
It is the right distance from the Sun to allow water at all stages to exist. IT also has a protective atmosphere that allows radiation to enter, but not harm life. The greenhouse gases also keep the surface warm. The Earth also has the right chemicals for life including carbon and water. Also most of the carbon is stored in the lithosphere.
How close does land vegetation follow global precipitation trends?
Land vegetation follows precipitation closely! Areas where there is more precipitation and less evaporation also has more vegetation. Near the equator is a good example of this.
How soon after deposition does freshly fragmented debris undergo most chemical weathering?
Most chemical weathering happens within the first few thousand years, more fragmented rocks will weather faster due to more surface area.
Do positive feedbacks always make climate warmer?
NO! Positive feedback amplify change.
Do glaciations always occur when continent are located in polar positions?
No, there have been three main times of ice house climates, but in each of those times there is proof that there're times with no ice sheets.
Does each lithosphere plate correspond to an individual continent or ocean basin?
No, they contain a combination of both, for example the African Plate contains the majority of Africa and part of Eastern Atlantic Ocean.
Why are ocean sediments and ice cores especially important archives of climate
Ocean sédiment and ice cores are important because they have continuous records that are also high quality. They aren't affected by wind, waves, or erosion and therefor are very deep.
How is the polar position hypothesis tested?
Paleogeography is compared to the geologic record of ice sheet existence.
What are the major characteristics of the climate of Pangea?
Pangea had land masses as far north as Greenland and as far south as Antarctica, but no ice sheets formed. This leads us to believe that the temperatures were warmer than they are today. This higher temperature can be explained by the higher carbon dioxide levels in the atmosphere. The interior was extremely dry. This was because of the larger amount of land causing trade winds to lose most of their water vapor before reaching the interior. The coasts receive much more rainfall than coasts do today. Also there was a wide range of season temperatures as well as strong monsoons.
Describe how the products derived from physical and chemical weathering provide different kinds of information about the climate system.
Physical weathering can tell us about erosion and subsequent deposition of debris in ancient ice sheets, sand dunes moving across deserts, and deposition of water. They give us vague ideas about climate. Chemical weathering can tell us more detail about ancient climate including how much oxygen was in the air.
What does evidence from moraines in the Wind River Basin of Wyoming suggest about chemical weathering?
Rates of chemical weathering decrease exponentially with time after rocks are exposed at the surface
The climate system consist of many component with different response times. What is the total range over which these responses vary?
Response times vary from hours to 10,000 years. When dealing with things such as the atmosphere and land surface, responses happen as soon as hours where as ice sheets don't see responses for 100-10,000 years.
What effect does the formation of sea ice have on the overlying atmosphere?
Sea ice traps heat under itself, not allowing it escape into the atmosphere. It also creates an ice albedo effect causing a positive feedback keeping it cooler. This causes the air temperatures to drop as much as 30*C.
How does the resolution from sedimentary archives vary with depositional environemnts?
Some areas have a higher rate of deposition. The two factors that matter the most are the amount of disturbance that area has, or the how many things are digging, and the rate at which the record is being buried. An area with low disturbance and high burial rate will leave a much better record than an area with a high disturbance rate and low burial.
Explain how paleomagnetism tells us about rates of spreading at ocean ridges.
Stripe like patterns (magnetic lineations) in the ocean floor track the reversal of the magnetic poles. These changes can also be used to reconstruct the rate of seafloor spreading and compile them together to estimate the global mean rate of seafloor spreading.
What climate factors affect the removal of carbon dioxide from the atmosphere by chemical weathering?
Temperature, precipitation, and vegetation are all the big factors that affect the atmosphere and increase chemical weathering.
Why is chemical weathering faster in the eastern And then in the Amazon lowlands?
The Andes have high weathering rates because of active uplifts and are continually processing fresh supplies of rock prone to weathering. The Amazon lowlands have a slower rate because one they are lowlands and two because the unweathered rock is buried under a protective layer of weather rock.
Fast subduction in the modern Pacific Ocean carries down sediments with low amounts of CaCO3, while almost no subduction occurs in the Atlantic, with it carbon rich sediments. What would happen if subduction suddenly began in the Atlantic and replaced an equal amount of subduction in the Pacific?
The Atlantic Ocean would close and the Pacific Ocean would continue to grow and we would move towards Europe and Africa. Carbon dioxide emissions from volcanic activity would increase because increased subduction of carbonate.
What evidence suggests that Earth has always had a long-term thermostat regulating its climate?
The Faint Young Sun paradox supports the idea of a thermostat. This suggests that the early atmosphere was much stronger in order to prevent a completely frozen planet. The planet also buries carbon and releases carbon as needed to maintain temperature.
Where did the extra carbon dioxide from Earth's early atmosphere go?
The extra carbon dioxide got dissolved in the oceans and because part of the limestone. Today it is trapped in the rocks and mountains around us.
What role does chemical weathering play in the BLAG hypothesis?
The faster the rate of sea floor spreading, they higher the concentration of carbon dioxide will be emitted into the atmosphere causing warming which will increase the silicate weathering rates.
Glacial ice is a valuable climatic archive because..
The ice contains geochemical proxies of atmospheric composition and temperature of the past, annual layers are often resolvable, enabling age determination and correlation, and the geographic distribution of coring sites ranges from the tropics to both polar regions.
What kind of physical behaviors in Earth's deeper layers allows the plates to move?
The mantle is largely solid and has a high temperature and pressure. This pressure and temperature is always pushing against the crust and drives movement.
What processes cause air to rise from Earth's surface?
The process of surface heatings and free convection cause air to rise. Air is heated by solar radiation and this causes it to expands and become lighter making it rise.
How does solar radiation arriving on Earth differ from the back radiation emitted by Earth?
The radiation arriving on Earth is called shortwave while the radiation emitted back is long wave radiation. 70%os shortwave radiation is absorbed and the other 30% is reflected dirty back into space. Longwave radiation is heat lost
In the example in which the Bunsen burner is lit and the beaker of water at first warms quickly and then more slowly, does the response time of the water change through time?
The response time doesn't change, however the rate of warming slows.
Describe the main pathways by which heat in the atmosphere is transported towards the poles.
The two main pathways are the intertropical convergence zone and the Hadley cell. Heated air rises in the tropics at the ITCZ then sinks in the subtropics and moves to the Hadley call. The Hadley cell moves the hot air away from the equator and towards the poles.
Why does deep water form today at higher latitudes?
The two processes that form deep water circulation are temperature and salinity. On average the salt content is 3.5% and that makes the salt water denser causing it to sink. The cooler temperature causes the water tossing further creating a conveyor belt motion pulling the water down and around.
Why does rain fall on the sides of mountains in the path of wind from nearby oceans?
The wet air mass is driven up the mountain by winds. As the mass rises and cools, it condenses can produces perception. As it reaches the peak, it runs out of water vapor and warms on the way down making warm and dry climates on the back sides of mountains. (rain shadow effect)
How could chemical weathering be both the driver and the thermostat of Earth's climate?
Uplift only takes place over about 1% of the Earth. This causes weathering and cooling. But with other 99% of the surface not being actively uplifted which would slow the cooling rates. They balance themselves out.
What increases the rate of chemical weathering of rock
Vegetation, Temps, Precipitation
Why is Venus so much warmer than Earth today?
Venus receives twice the amount of radiation and the atmosphere has much more carbon dioxide so it creates a stronger greenhouse effect.
Why is volcanic inout of carbon dioxide to Earth's atmosphere not a candidate for its thermostat?
Volcanos do not react to external changes or act to moderate their effects. Volcanos drive by heat sources located deep in its interior and removed from contact with the climate system.
Which tow major groups of organisms are most important to climate reconstruction over the past several million years?
We look at pollen on land and plankton in the oceans.
Why does the Faint Young Sun pose a paradox?
With the Faint Young Sun, it tell sis that the Earth should have been frozen for the first 2/3 of history, but we know that is not true. Also with the increasing Sun's heat, Earth should become too hot to be habitable, but that also hasn't happened.
When carbon dioxide combines with water in the atmosphere _____ is formed.
carbonic acid
The BLAG spreading rate hypothesis proposes how:
plate tectonic-control processes controlled carbon dioxide input into the atmosphere and ocean, thus influencing long-term global climate trends
What factor partially accounts for aridity in the low-latitude interior of Pangaea?
large areas of land located under the dry descending limb of the Hadley circulatio
Article
lead hypothesis, data, conclusion. Look at notes in paper
Each of the following is a component of the climate system and varies in response to external climate forcings except plate tectonics the atmosphere ice the ocean
plate tectonics
Chemical weathering increases when
there is an increase in the rate of physical weathering