Geol Exam 3

Geol Exam 3 - Name _______________________ GEOL 125: Exam...

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Unformatted text preview: Name _______________________ GEOL 125: Exam III Sample Questions I. Multiple Choice Quickies: Choose the letter corresponding to the best choice. Read answer choices carefully 1. 2. 3. Galaxies are held together by: a) gravitational forces; b) the strong force; c) the electromagnetic force; d) radiation pressure from the 3K BBR; e) gluons. Most of the elements found on earth: a) have existed forever, b) were created during the big bang; c) were formed by nuclear reactions in stars; d) formed when the solar system formed. In analyzing the behavior of Earth systems, negative feedbacks provide ________, while positive feedbacks provide _______. a) stability, amplification; b) amplification, stability; c) chaos, little effect; d) stochastic behavior, little effect. Average Earth surface temperature: a) depends only on solar output; b) has been the same through geologic time; c) depends on radioactive decay in the earth interior; d) is regulated by a balance between absorption of incoming radiation and emission of outgoing radiation. During much of the Cretaceous, the Southern and Central US was: a) covered by sea water; b) not yet formed; c) the cradle of civilization; d) a desert; e) politically conservative. In describing the greenhouse effect, the wavelengths in the electromagnetic spectrum for the 'window in' and the 'window out' (respectively) are in the: a) UV & visible; b) visible & infra-red; c) visible & UV; d) infra-red & visible; e) visible & radio. 4. 5. 6. 7. In the Hadean, plate tectonics may have been different than at present because: a) solar radiation was smaller ; b) the core had not yet formed, c) the lithosphere was much thinner, d) radioactive decay had not yet begun. 8. 9. Deterministic behavior in a non-linear system can sometimes result in: a) confusion; b) inflation; c) chaos; d) heat transport; e) global warming. The Milankovitch curve is an indicator of seasonality in the N. hemisphere, which varies due to: a) Earth orbital eccentricity; b) Earth precession; c) influences of other planets on Earth's motion; d) all of the above. 10. One factor that probably caused human ancestors to emerge from the trees include is: a) lowered sea level; b) development of binocular vision; c) expansion of grasslands; d) increased rainfall. II. Timing of geologic events. What is the geologic or absolute age of the following? Choose the best answer from the list given. (10 pts): 11. Death of the dinosaurs: a) Proterozoic; b) end of Cretaceous; c) start of Cambrian; d) end of Paleozoic; e) latest Pleistocene. Name _______________________ 12. Mammals become abundant: a) Carboniferous; b) early Holocene; c) start of Cambrian; d) Cenozoic; e) Mesozoic. 13. Oxygen in the atmosphere become abundant about: a) 3.8 by ago; b) 3.5 by ago; c) 2.1 by ago; d) 540 my ago; e) 15 ky ago. 14. How old (all in billion years) are the oldest Earth rocks (not counting detrital zircons)?: a) 4.5; b) 3.9-4.0; c) 3.5; d) 3.0; e) 0.6 III. Geoart (11 pts) a) Draw a graph illustrating the concentration of atmospheric CO2 during the last 150,000 years. Be sure to label axes and indicate the present. (3 pts) How was this information obtained? (1 pt) IV Quickies: Fill in the blank spaces with the word, number, or phrase that is most appropriate. (9 pts, one for each letter) a) Write a reaction expressing photosynthesis (you may use symbols or words): b,c) We identified 5 factors that strongly influence Earth's average climate. List 4 of them below: 1. __________________________________ 3. __________________________________ 2. __________________________________ 4. __________________________________ V. Puzzlers. Briefly try to explain the following. (4 pts) a) Mars receives less than half as much solar radiation as the Earth (per unit area). It is so cold that any water that is present today is frozen in icecaps or in the Martian soil. However, landforms on Mars have distinct shoreline features around large basins. These features indicate that liquid water once existed on Mars. How could this be possible on such a planet that is so far from the sun? Hints: In answering this question, you might find it useful to know that Earth and Mars have similar chemical compositions, but the mass of Mars is only 10% of the mass of the Earth. The present Martian atmosphere is very thin, but does contain a little CO2. Some very large volcanic structures can be seen on Mars, but we have never observed an eruption. (2 pts) ...
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This note was uploaded on 03/03/2008 for the course GEOL 125Lxg taught by Professor Hammond during the Fall '07 term at USC.

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