Quiz #5 -- Processes and Concepts of Geology
September 19, 2003

1. What are the three sources for water made available to a metamorphosing rock?

Pore waters: sediments contain much water in pore spaces between grains; this water is driven out of the rocks with increased temperature and pressure of metamorphism.

Breakdown of hydrous minerals: some minerals contain water in their structure; this water is also driven out of the rocks with increased temperature and pressure.

Magmatic water: water can also leak out of magma during intrusion of a relatively “wet” silicic magma.

2. Fluids have two primary effects on a metamorphosing rock. What are they?

Fluids bring in new ions: these waters circulate through the sedimentary package and carry dissolved chemical constituents that can help to form new minerals in a metamorphic rock.

F luids also greatly enhance the rates of mineralogic changes (reaction rates).

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Bonus Questions: Always optional. One point for each correct answer.

Forbes magazine announced its list of the richest Americans. Who is at the top? Bill Gates

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