Podcast
Questions and Answers
What characterizes metaluminous rocks in terms of aluminum content?
What characterizes metaluminous rocks in terms of aluminum content?
Which minerals are characteristic of SiO₂-undersaturated metaluminous rocks?
Which minerals are characteristic of SiO₂-undersaturated metaluminous rocks?
What does a negative aluminum index (A.I.) indicate about a rock?
What does a negative aluminum index (A.I.) indicate about a rock?
Which minerals would you expect to find in SiO₂-saturated peralkaline rocks?
Which minerals would you expect to find in SiO₂-saturated peralkaline rocks?
Signup and view all the answers
How does the presence of trace elements relate to igneous rock classification?
How does the presence of trace elements relate to igneous rock classification?
Signup and view all the answers
Study Notes
Feldspathoid-Silica Saturation Index (FSSI)
- The FSSI classifies igneous rocks based on the presence of certain minerals.
- Metaluminous rocks have a positive aluminum (Al) content.
- Peralkaline rocks have a negative aluminum (Al) content.
- Silica-undersaturated rocks contain minerals like nepheline, calcic or sodic pyroxenes, and amphiboles.
- Silica-saturated rocks contain minerals like quartz, ferric, magnessian, or calcic pyroxenes, and amphiboles.
- Quartz-saturated rocks have an excess of quartz over leucite and nepheline.
- Silica-undersaturated rocks have a negative amount of quartz over leucite and nepheline.
Trace Elements
- Trace elements are used to characterize igneous rocks.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on the Feldspathoid-Silica Saturation Index (FSSI) and how it classifies igneous rocks. This quiz covers the distinctions between metaluminous, peralkaline, and various types of silica-saturation in rocks, as well as the role of trace elements in characterization.
