Introduction to MineralogyDr. Tark Hamilton

Chapter 5: Lecture 17Earth’s Chemistry & Minerals

Camosun College GEOS 250

Lectures: 9:30-10:20 M T Th F300

Lab: 9:30-12:20 W F300

Ternary Plot: Feldspar Composition

Alkali Feldspars

Plagioclase

Anorthoclase

Sanidine

Solvus

Subdivisions of Earth’s interior

1Kbar = 100 MPa

Oxygen 94% 8 Elements=99%

Fe98% Ni2%Fe80% Ni20%

“Perovskite”“spinel”

Olivine

Peridotite

Granodiorite

Widmanstaaten pattern: “Gibeon” meteorite, Namibia, FeNi (111) exsolution

The “Big 8” Elements:Earth’s Crust

Cumulative CationPore VolumeEstimates from Till & Crustal Rocks

Waters: (Na+ >Ca+2 >K+ >Mg+2 >Fe+2 >SiO2 ) & [Cl- >(HCO3) - >(SO4)-2] TDS<3ppt

Elemental composition of Crust

Alta’ameem Meteorite, Iraq: Chromite, Ilmentite, Troilite

Apollo 12 Oceanus ProcellarumBasalt: Chromite, Ulvospinel, FeNi

PlagioclasePyroxene

Garnet Peridotite: Alp Arami SZ

Woudloper

Phase Transitions: Peridotite

olivine

Spinel

perovskite

Pressure compresses Volume

Perovskite: CaTiO3 Structure

Si4+ Al3+

Ca2+ Mg2+ Fe2+