Geology Test 3
Terms in this set (64)
Ice is to glaciers as _________
What are the two principal gases that make up 99% of dry air?
nitrogen and oxygen
Which is the most accurate statement about sea level changes over Earth's history?
Sea level is rising and but has been higher in the geologic past
The last ice age occurred because more land area was located close to the Poles.
Which factor do scientists believe is most responsible for increases in Earth's temperature over the
Increases in the concentration of carbon dioxide, methane and some other atmospheric gases
A sample igneous rock formed with 500 grams of the parent isotope, Carbon-14, which has a
half-life of 5,730 years. The same igneous rock now contains 125 grams of Carbon-14 and 375
grams of the daughter isotope Nitrogen-14. The rock has been through ___ half-lives and is
2; 11,460 years
Sedimentary over igneous or metamorphic. In which the underlying strata are composed of igneous or metamorphic rock and the overlying strata are composed of sedimentary rock.
An angular unconformity is an unconformity where horizontally parallel strata of sedimentary rock are deposited on tilted and eroded layers, producing an angular discordance with the overlying horizontal layers.
Sedimentary over sedimentary. A type of unconformity in which erosion or lack of deposition has occurred between two parallel sedimentary strata.
After two half-lives, the ratio of parent to daughter isotope is 1:
Which of the following might describe sediment deposited by a glacier
Poorly sorted; angular
Which of these two valley shapes would you expect a glacier to create?
What would happen to Earth's albedo during an ice age?
The average albedo of Earth's surface would increase.
The last ice age can be divided into ______________________________ and ____________________________.
long cold glacials; short warm interglacials
How often do ice ages occur in Earth's history and how long do they last?
At irregular intervals, approximately one every 200 million years and they last for millions of years
On the basis of the discussion in the video, explain what you think is happening to the ice in the Arctic Ocean in terms of a negative climate feedback cycle that results in a decrease in ice volume.
Sea ice is melting which is causing the surface of the water to attract and absorb more sunlight which is heating up the water temperature resulting in less ice production
Identify three things or features you could use to identify the climate of a region if you couldn't use weather data
Types of vegetation, soil, or animals present; geologic formations (e.g. siltstone vs. sandstone as an indicator of current strength in a body of water), weathering of rocks.
Think about all the things we have investigated in class so far this semester. Identify three examples of climate-related aspects of the Earth system that we have discussed in the class.
Weathering of rocks in canyons or valleys due to wind or water action; sediment transport (how far grains or clasts go based on the strength of the agent); elevation of volcanoes or mountains have a strong influence on average temperatures
How many flow cells are present in the Northern hemisphere?
The equator receives more solar radiation than the poles. What happens to air at the equator?
Which part of the Northern hemisphere exhibits air that moves vertically in a similar manner to air at the equator?
Due to Earth's rotation, winds in the Northern hemisphere are deflected to the __________ of their course
Right - clockwise
A rainforest would be most likely found under what conditions
Rising air at the equator
Most of the world's deserts are located at what latitudes
30 N and S
Identify the vertical movement of air above desert regions
Predict precipitation volumes at the South Pole on the basis of air movement
Which processes result in the decrease in the atomic number of an isotope following radioactive decay?
If radioactive decay began with 400,000 parent isotopes, how many parent isotopes would be left after 3 half lives
Approximately what age was determined for the oldest rocks that have been found on Earth?
4 billion years
Isotope X has a half-life of 10 days. If you began an experiment with a 400-gram sample of the isotope, how much isotope X would be left after 20 days?
The half life of the isotope Uranium-238 is 4.5 billion years. The oldest rocks on Earth would contain approximately 52-55% of their original store of this isotope.
Put the following three units of time in order from shortest to longest.
Century, period, era
Which of the following is interpreted to be the same age as Earth?
Meteorites, Venus, The Sun
Carbon dioxide was more abundant in Earth's early atmosphere than it is in the air we breathe today.
During which Eon did life on Earth become abundant
Identify which of the following statements are true.
The dinosaurs became extinct at the end of Mesozoic era. The first evidence of life on Earth is recorded in rocks approximately 3.8 billion years old.
Which rock unit would be most likely to exhibit contact effects?
Which rock unit is most likely to contain pieces of an older rock?
"Understanding geologic processes active in the modern world is crucial to interpreting Earth's past."
What is the name of this concept?
The sequence of events, places rocks units and geologic events in order, oldest to youngest
How geologist figure out the ages of rocks, and hence the age of Earth
Radio Active Decay
Decay occurs when an isotope loses or gains protons and/or neutrons (results in changes in atomic number and/or mass number)
Time for half of the parent isotope to be converted to daughter isotope ; as time passes, amount of parent isotope decreases, daughter increases (3/4).
Calculating the age of Rock
Number of 1/2 lives of radioactive isotopes x length of one half life
Sedimentary Rocks age can be determined by cross cutting
What causes seasons
The tilt of the axis points the Northern hemisphere towards the sun so its warmer
How would the total amount of isolation change at the equator if Earth's axis was vertical instead of tilited
Insolation would increase
What must happen to the tilt angle of Earth's axis in order to have vertical rays of sunlight strike the surface in NC durning the summer solstice
Tilt would increase
Why is Earth warm enough to support life
Infrared radiation from Earth's surface is absorbed by gases in the lower atmosphere
Shape of orbit changes distance to sun
Tilt of Access
Changes determine where solar radiation received
Direction of tilt of axis changes
Positive Climate Forcing
More absorption (planet warms)
Negative Climate Forcing
More reflection (planet cools)
What are the 2 most common gases in Earths atmosphere
Oxygen and nitrogen
Predict the average annual temperature at Earth's surface
Approximately what proportion of Earths atmosphere is composed of carbon dioxide
Conditions of the atmosphere over a short period of time (minutes to months), eg temperature, humidity, precipitation, cloudiness
How the atmosphere "behaves'" over relatively long periods of time (seasons and longer) Changes in long term averages of daily weather
What causes the seasons
The tilt of the axis points to the northern hemisphere towards the sun so it receives more concentrated energy during the summer
Time Scale Phanerozoic Era
1. Paleozoic : "ancient life "
-first common organisms with hard skeletons
-fist land plants
-ages of fishes
-insects and early reptiles on land
2. Mesozoic : "middle life"
-early dinosaurs and Age of the reptiles
-first grasses and flowering plants
3. Cenozoic : "recent life"
-large mammals abundant
Abundant marine organisms with hard shells
Age of Fishes, large coral reefs, primitive land plants, first insects
Evergreen trees, amphibians and early reptiles on land
Age of Dinosaurs, first birds, first grasses and flowering plants, large marine reptiles, early mammals
Age of mammals, first large mammals, horses, bears common
Ice age in northern Hemisphere, mammoths, first humans, modern organisms