Igneous Rock Exercise Homework #4     Due on Wednesday, Feb 18, 1998.

Instructions:  Answer (typed!) all the questions using your notes, textbook, lab book and any other references you can find (if needed).  Do Assignment #3 before #4.

Scenario: While on a scuba diving vacation to a remote and very beautiful island in the South Pacific, you take a break from diving and backpack for a couple days back into the mountainous region of the island's interior.  You happen upon a small village located near the base of a 1000 meter tall, very steep volcano which appears (to you) to be dormant.  The village is located along the bank of the main stream draining the south flank of the volcano.  The villagers inform you that last week one earthquake knocked them out of bed and the volcano smoked for two days with a number of smaller earthquakes.  After revealing your geological background (only this one course) you are feasted regally, treated to the local fermented beverage and escorted up the volcano the next day with the village elders.  The volcano is emanating a thin ribbon of smoke at the top.  You have a headache and feel nauseous from your royal treatment the night before.
 

Answer Questions 5-6.  Write paragraphs with complete sentences; don’t use short answer/outline style.

5.  Carefully read p. 83-89 in the textbook.  It discusses the distribution of active volcanoes in relation to plate tectonics and how melting of rocks takes place.  It also lays out the essential differences between subduction zone volcanism and intraplate volcanism (pay attention to oceanic, not continental, for this assignment).
 Which type of volcanic island (island arc or hot spot) is the composition of the volcano in Homework #3 compatible with?  Support your answer by discussing the origin of this magma from a plate tectonic and magmatic differentiation standpoint (how does partial melting or fractional crystallization play a role in the origin of this magma).

6.  Write a brief (one full page minimum, but longer is fine if you get into it) fictional account of the end of the story from Homework #3.  Specifically answer the needs of the village elders.  Is their village in danger?  Although the most recent eruptions appear to have been non-violent and non-explosive, will future ones be as well?  Should they expect to die an explosive, fiery death or will they simply walk away as the lava flows slowly down the volcano?  What other possible geologic hazards should they be on the lookout for?
 Make this an actual work of fiction, with interesting characters, dialogue, plot, intrigue, etc.  Put whatever geological information into this story that it will hold without destroying the artistry of the literary work.  Remember that most word processors have spelling checkers associated with them for your convenience (and your grade).  Humor is appreciated (a lot of grading to do here).
 

Grading Rubric (points awarded out of 5 possible):
5 pts = Well-written and grammatically correct sentences; answers or information is factually correct; depth of information is at a college level (not just very basic information).
4 pts = Work is substantially correct and well-written, although it may include one or more minor problems with presentation or with correctness of answers.
3 pts = Work includes one or more major problems with presentation or with correctness of answers.
2, 1 or 0 pts = Work has substantial flaws in presentation and content.