Midterm Exam Questions -
Q1. You are asked to evaluate a construction/building project in an area corresponding to the sketch map below. The area has mildly hilly topography and thin soil cover. The bedrock in area X is dominated by the mineral Spinel and the bedrock in area Y is dominated by the mineral Talc. A thin vein follows the contact between areas X and Y and this vein contains the mineral Cinnabar. The project is to construct a flat road, using either route A or route B, into the building site -Site- where an apartment complex will be built. You are being asked to evaluate this project in terms of construction costs, long term stability (and associated road maintenance costs), and health/safety (make sure you address these in your answers below).
a) Look up the properties of Spinel, Talc, and Cinnabar in the table below and list the properties you believe are pertinent to this consulting job and explain your choices.
b) Are you going to recommend road route A or road route B? Why? (Make sure you explain what is preferable about your chosen route and what is wrong with the route you reject).
c) Do you agree with the choice for the location of the building site? Why or why not?
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Chemistry
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Luster
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color
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Streak
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Hardness
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Cleavage
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Density
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Cinnabar
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Mercury sulfide
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Adamantine
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Tint or shade or red
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Red-brown
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2 - 2½
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1 - Perfect
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8.2 g/cm3
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Spinel
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Magnesium aluminum oxide
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Transparent, Translucent
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Black, blue, red, violet, green, pink
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7½ - 8
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None
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3.9 g/cm3
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Talc
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Magnesium silicate hydroxide
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Waxy, Greasy, Pearly
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White, pale of green, brown, gray
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1
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1 - Perfect
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2.7 g/cm3
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Q2. Interpret the geologic history of the crustal block pictured below. Note that the same rock formation exists wherever you see the same fil pattern.
List the geologic processes/events represented by the named rock formations and the labeled contacts in the order in which they occurred, beginning with the oldest and ending with the youngest.
For each rock formation name the major rock type that the named rock belongs to and briefly describe how that rock was formed. For numbered re-occurrences of the same rock name you do not have to repeat the description of how it was formed.
Identify geologic contacts C1, C2, and C3 in terms of what each would be called (be specific) and briefly describe the process(es) that formed it.
Q3. You are asked for your recommendations by a real estate tycoon who wants to build a major resort on a tropical island. He has his eye on two islands that are currently uninhabited and available for the right price. Both are volcanic islands, but "Atlantica" is in the middle of the Atlantic Ocean and "Pacifica" is near the western rim of the Pacific Ocean basin.
a) For each island, what type of tectonic plate boundary is most likely nearby - directly associated with the local volcanism?
b) What is likely to be the general compositional type of the volcanic magma on Atlantica and on Pacifica and what are the important physical properties of each magma type.
c) Describe the type and severity of volcanic hazards that will be associated with each island and compare the islands to each other in terms of volcanic hazard risk.
d) Which island has a lower risk of being hit by a Tsunami in the next 100 years and why?
e) Which island are you recommending for the resort development and why?