3_Minerals - Silicate families Isolated tetrahedra: olivine...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Silicate families Isolated tetrahedra: olivine group Single chains: pyroxene group Double chains: amphibole group Sheets: micas and clays Network: quartz and feldspar Trends Non-silicates The Rock Cycle Igneous Rocks Chapter 3: Minerals and Chapter 5: Igneous Rocks Next lecture: Continue chapter 5 8 elements make up 99% of the Earths crust oxygen (O) and silicon (Si) most abundant Composition of the Crust (Table 3-1) Silicon and oxygen are the major two atomic constituents of the crust. By necessity, then, silicates are the most abundant and important minerals. The Silicon-Oxygen Tetrahedron silicates : class of minerals whose crystal structures include Si+O tetrahedrons [SiO 4 ]-4 . (Figure 3-12) The silicon tetrahedron is the fundamental building block of virtually all silicate minerals. It is a very robust structure, able to hold up even in the high- temperature, high-pressure conditions of the mantle. Silicate families Isolated tetrahedra: olivine group Single chains: pyroxene group Double chains: amphibole group Sheets: micas and clays Network: quartz and feldspar Trends Non-silicates The Rock Cycle Igneous Rocks Chapter 3: Minerals and Chapter 5: Igneous Rocks Next lecture: Continue chapter 5 isolated tetrahedrons: no sharing of oxygen atoms ferromagnesian Fe and Mg rich; mafic refractory: high melting point principal mineral of the upper mantle olivine Silicate Families: Olivine group The elements in olivine (Table 3-1) Iron and magnesium are virtually interchangeable in many mineral structures, because of their identical charge (in most cases) and similar ionic radii. Position in the periodic table does not necessarily predict either ionic radius or preferred ionic charge, although it can be helpful for that. However, it does tell us relative mass, and so we can see that the more iron a mineral has, the more dense it is compared to minerals containing the other common atoms. Even magnesium tends to increase mineral density, as its charge does not need to be compensated by as many bulky oxygens as silicon. (Figure 3-15)...
View Full Document

Page1 / 30

3_Minerals - Silicate families Isolated tetrahedra: olivine...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online