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GEOLOGICAL SCIENCES 0050
I am aware of the Brown honor code, of the fact that this exercise falls under that code, and of the penalties for
violating that code.
Signature:____________________________________
Name:_______________________________________
Student ID#__________________
EXERCISE 5:
VENUS GEOLOGY AND ITS INTERPRETATION
(20 points; 100 possible answers, 1/5 point each)
Due: Friday, December 5, 2014
Introduction and Background:
In the lectures, reading, and discussions, the questions were posed:
1) "Is Venus similar to the smaller terrestrial planetary bodies (Moon, Mercury and Mars) in terms of its
surface geologic characteristics?", or
2) "Is Venus (which is similar to Earth in its position in the Solar System, its size and density) more like
the Earth in terms of its surface characteristics and processes?"
The answers to these questions have been partly revealed by the Soviet Venera 15-16 and the U.S. Magellan
missions, which provided high-resolution global image coverage. These questions are also the subject of
current research in planetary geological sciences and this exercise is designed to give you the opportunity to
assess the characteristics of Venus as a planet and draw your own conclusions to address these questions. The
textbook Exploring the Planets was first published in 1995 (with updates to the online version we are using).
Images that may be helpful for this exercise can be found at http://www.jpl.nasa.gov/magellan/images.html.
and the specific URLs indicated. In addition to the book and online resources described above, you can also
explore Venus through Google Venus, which is available through the attached .kmz file, just like the ones that
you used for Google Earth, Moon and Mars. To use this .kmz file, just follow the instruction from previous
Google Geo 50 exercises. Read over the exercise, use the online images to help find the answers, fill out the
answer sheet and return the completed exercise answer sheet to your TA’s mailbox in Lincoln Field Building.
Use the accompanying answer sheet for this exercise. Circle only those that are correct on the
accompanying answer sheet; there may be more than one correct answer for questions that have
multiple options, like a,b,c,d, etc):
A. Nature of Venus and Previous Exploration: What are the main similarities and differences between
Venus and the Earth?
1. Venus is larger than Earth.
2. Venus is smaller than Earth.
3. Venus' rotation period is much longer than that of Earth.
4. Venus rotates around its axis in the same direction as the Earth.
5. Venus' surface atmospheric pressure is less than that of Earth.
6. Venus' surface atmospheric pressure is over 90 times greater than that of Earth.
7. Venus is less dense than the Earth.
8. Venus is denser than Earth.
9. Venus' atmosphere has carbon dioxide in the same abundance as Earth's atmosphere.
10. Venus' average surface temperature is 2.5 times greater than that of Earth in Kelvin.
11. Venus' surface is colder than Earth.
12. Venus' orbit is ~42 x 106 km closer to the Sun than Earth's, but Earth's orbit is closer to Venus' than to
Mars' orbit.
13. The Soviet Union tried many times but could only land two spacecraft on the surface of Venus.
14. Pioneer-Venus was a United States mission that had atmospheric probes and a radar altimeter.
15. The Pioneer-Venus (PV) topographic map had an average resolution of 100 m.
16. The chronologic sequence of missions was 1) Pioneer-Venus, 2) Magellan, followed by 3) Venera 15-16.
17. Pioneer-Venus provided data that showed the range of elevations on Venus was similar to the Earth.
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18. The frequency distribution of elevations on the PV map was similar to that of Earth, providing evidence of
plate tectonics.
19. The discovery of parallel folds in mountain belts on the PV map further supported a plate tectonics origin.
20. The Venera 15/16 landers revealed platy and fragmented surface rocks and showed that they were granitic.
B. The Distribution of Topographic and Geologic Features on the Surface of Venus:
1) Topographic Features:
21. PV topography revealed the surface of Venus could be divided into three provinces: lowlands, uplands and
highlands.
22. Venus topography is characterized by:
a. About the same range as Earth but the distribution is different.
b. Northern lowlands and southern highlands similar to Mars.
c. A trimodal frequency distribution in contrast to that of the bimodal Earth.
d. No real evidence for topography like that of folded mountain belts on Earth.
e. Several large highland areas including Beta Regio, Atla Regio, Alpha Regio, Aphrodite Terra, and
Ishtar Terra.
f. Steep trenches such as Diana and Dali Chasma, located in Aphrodite Terra.
g. The highest point on the planet, the 11 km high summit of Maxwell Montes.
23. Alpha Regio is a highland region consisting of complex terrain of intersecting ridges, troughs, and flatfloored valleys. The dark volcanic plains surrounding Alpha Regio are:
a. Older than Alpha Regio.
b. Younger than Alpha Regio.
c. Of the same age as Alpha Regio.
2) Volcanic Features:
24. Magellan images revealed that the % of the surface occupied by volcanic rock was:
a) <25%.
b) ~33.3%
c) ~45%
d) ~65%
e) >65%.
25. Volcanic activity on Venus is characterized by:
a. A few hundred small shield volcanoes less than about 15 km diameter.
b. Large lava flows that extend many hundreds of kilometers.
c. Maat Mons, only about 2 km high, is much smaller than the Hawaiian volcano Mauna Loa.
d. Large plinian eruption columns.
e. Some volcanoes that may still be active.
f. One deposit, covering over 100,000 km2, from the volcanic source Ammavaru.
g. No signs of pyroclastic explosive eruptions because of the high pressure.
h. Dark surfaces, indicating very rough, and bright, indicating smooth surfaces.
i. Some very fluid eruptions and/or very high eruption rates.
j. Pancake-like domes over 20 km in diameter and up to 750 m high.
k. Long narrow sinuous channels, one of which is 7000 km long, that may be due to thermal erosion.
l. Sapas Mons, in Atla Regio, which has a height only one two-hundredth of its width.
m. Lava flows that emerge from volcanoes, cracks in the crust and depressions.
26. These volcanic rocks occur mostly in the form of:
a. Oceanic crust with a morphology similar to Earth's spreading centers and seafloor.
b. Lava flows forming regional plains.
c. Mount Saint Helens-like composite volcanoes with ash and lavas intermixed.
d. Billions of large Hawaii-scale shield volcanoes.
27. The surfaces not covered by volcanic rock are composed of:
a. Ancient high-standing structures exactly like continents on Earth.
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b.
c.
d.
e.
Large depressions that appear to be subduction zones similar to Earth.
Sandstone and limestone, much like sediments on the Earth’s seafloor.
Volcanic edifices that have been destroyed beyond recognition by tectonic activity.
Mountainous areas that have been deformed repeatedly.
3) Tectonic Features:
28. Tectonic activity on Venus is characterized by:
a. Some areas, named tessera, that are very complexly deformed, and stratigraphically old.
b. Graben-like features indicating that forces of compression are widespread.
c. Sinuous ridges similar to the wrinkle ridges observed in the lunar maria.
d. Large mountain ranges formed in a manner similar to those on the Moon.
e. Major amounts of strike-slip faulting with offset like the San Andreas fault.
29. Coronae on Venus:
a. Are characterized by a deformed annulus.
b. Are similar to circular to ovoid features with outwardly extending fractures, called arachnoids.
c. Commonly contain evidence of both tectonism and volcanism.
d. Are most like hot spots on Earth.
e. Are generally several hundred km wide, but the largest, Artemis Corona, is 2100 km in diameter.
f. May reflect deep interior mantle processes that uplift and deform the surface.
g. Are not widely distributed on the surface.
h. Are usually between 1000 and 1200 km in diameter.
4) Impact Craters:
30. Impact cratering on Venus is characterized by:
a. Large ancient multi-ringed basins like those on the Moon, Mars and Mercury.
b. Clusters of craters showing that projectiles break up in the dense atmosphere.
c. Giant dark parabolas caused by interaction of the expanding ejecta plume with the upper atmosphere.
d. One 72 km diameter crater that has flows that travelled up to 300 km from the crater walls.
e. Craters which mostly have not been significantly altered by erosion.
f. Few craters less than about 15 km in diameter.
g. Over 10,000 impact craters distributed mostly in the ancient tessera terrain.
h. Mead crater, the largest impact crater on Venus, about 100 km in diameter.
i. Few small craters because they are apparently broken up by the atmosphere.
j. Some dark haloes caused by intense atmospheric shock waves.
5) Erosional and Eolian Features:
31. Venus is characterized by a lot of erosion and sediments, because it is so hot that the rocks bake, crack in
the heat, explode and fall apart.
32. The images taken by the Soviet Venera landers were disappointing because they saw no rocks, only soil.
33. Eolian activity on Venus is characterized by:
a. Wind streaks that are commonly located near topographic barriers.
b. Features that show that the winds are blowing from the equator to the poles.
c. Blizzard-like conditions with snow deposition in topographic lows.
d. Only a few meters of movement because the wind can't blow very hard.
e. Being located near sources of sediment.
f. Providing evidence for the distribution of Venus' global wind patterns.
g. Sources of sediment that are most commonly from impact craters.
h. Dunes that are hundreds of meters in width.
C. Synthesis and Geological Evolution of Venus:
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34. Venus is similar to the smaller terrestrial planetary bodies (Moon, Mercury and Mars) in terms of its
surface geologic characteristics.
35. Venus (which is similar to Earth in its position in the Solar System, its size and density) is more like the
Earth in terms of its surface characteristics and plate tectonic processes.
36. Venus is currently a “one-plate planet” but may have once been characterized by plate tectonics.
37. The surface geologic units reveal a rich record of the first 85% of the geologic history of Venus.
38. Little deformation or volcanic activity has occurred in the last ~500 million years.
39. Venus currently lacks abundant water, a hydrologic system, and plate tectonics.
40. Venus apparently underwent catastrophic tectonic and volcanic resurfacing about 500 million years ago.
41. Mantle plumes, in the form of surface coronae and large shield volcanoes, are very important in the crustal
evolution of Venus as seen in abundance in the preserved geological record.
42. Samples returned from the surface of Venus would provide significant information about the overall
geologic history of Venus.
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I am aware of the Brown honor code, of the fact that this exercise falls under that code, and of the penalties for
violating that code.
Signature:____________________________________
Name:_______________________________________
Student ID#__________________
GEOLOGICAL SCIENCES 0050 - EXERCISE 5:
VENUS GEOLOGY AND ITS INTERPRETATION
ANSWER SHEET (20 Points Total; possible answers, 1/5 point each)
Due: Friday, December 5, 2014
Circle only those that are correct on the answer sheet; more than one correct answer may apply for each
individual numbered question with letters:
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