Question:
Which one of the following is NOT an ultramafic rock?
Which one of the following is NOT an ultramafic rock?
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Remember that ultramafic rocks are rich in iron and magnesium, with olivine and pyroxenes being their major minerals.
Updated On: Sep 6, 2025
- Wehrlite
- Olivine websterite
- Harzburgite
- Anorthosite
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The Correct Option is D
Solution and Explanation
Ultramafic rocks are those composed primarily of mafic minerals, particularly olivine and pyroxenes, with very little silica content. Wehrlite, olivine websterite, and harzburgite are all ultramafic rocks, as they predominantly contain olivine and pyroxene minerals.
However, anorthosite is not ultramafic. It is a rock primarily composed of plagioclase feldspar, which is a felsic mineral, not a mafic or ultramafic one.
Thus, the correct answer is option (D). Final Answer: \[ \boxed{\text{Anorthosite}} \]
However, anorthosite is not ultramafic. It is a rock primarily composed of plagioclase feldspar, which is a felsic mineral, not a mafic or ultramafic one.
Thus, the correct answer is option (D). Final Answer: \[ \boxed{\text{Anorthosite}} \]
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