1. What type of feldspars would form from the cooling of a magma that was a mixt
ID: 154734 • Letter: 1
Question
1. What type of feldspars would form from the cooling of a magma that was a mixture of 33.3% K + 33.3% Na + 33.3% Ca and all the Si, Al, and O that feldspars need?
2. In a normally zoned plagioclase feldspar, what cation is enriched in the core of the grain and what cation is more enriched towards the rim of the grain? Which part of a normally zoned plagioclase feldspar has more Al?
3. Which alkali feldspar is stable at higher temperature, sanidine or microcline? What is the structural difference between these two feldspars?
Explanation / Answer
1. Barium feldspar and albite.
2. Na and Ca are present towards the rim; Al is enriched in the core.
3. Sanidine is stable at the highest temperatures, and microcline at the lowest.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.