TABLE OF CONTENTS

FOREWORD and EDITOR'S PREFACE AND ACKNOWLEDGMENTS (iii)

USEFUL REFERENCES (ix)

Chapter 1. The CRYSTAL CHEMISTRY and STRUCTURE of OXIDE MINERALS as

EXEMPLIFIED by the Fe-Ti OXIDES Donald H. Lindsley

INTRODUCTION L- 1

Techniques L- 1

Magnetic properties L- 2

THE CUBIC OXIDE MINERALS L- 4

Monoxides (Space group Fm3m) L- 5 Spinel group L- 7 Magnetite (Fes04> L-12 UlvSspinel (FegTiOg) L-15 Magnetite-ulv'ôspinel solid solutions L-15 Maghemite (y-Fe20s) L-18 Magnetite-maghemite solid solutions L-22 THE RHOMBOHEDRATitanomaghemitesL OXIDE S L-3L-214

Hematite L-34 Magnetic structure of hematite L-36 Curiej Nêel, and Morin temperatures of hematite L-37 Ilmenite L-38 Crystal structure of ilmenite L-38 Magnetic structure of ilmenite L-40 Crystal and magnetic structure of hematite-ilmenite solid solutions L-41

ORTHORHOMBIC OXIDES—THE PSEUDOBROOKITE GROUP L-44

The structure of pseudobrookite (Fe2Ti05) L-45

The Fe2Ti05-FeTi205 series L-45

STRUCTURES OF RUTILE, ANATASE, AND BROOKITE L-47

REFERENCES L-52

Chapter 2. EXPERIMENTAL STUDIES of OXIDE MINERALS Donald H. Lindsley

INTRODUCTION L-61

Control of experimental conditions L-61 Oxygen fugacity L-62 Container problems L-64 Experiments at very high pressures or high temperatures L-64 Minerals and phases considered L-65 FE-TI-0 SYSTEM

Fe-0 join L_66 Wustite L~67 Fe20s in magnetite L-67 L~67 Fe0-Ti02 join L_68 Fe2Û3-Ti02 join u

(iv) Fe0-Fe203-Ti02(-Ti203) join L-69 1300°C isotherm L-69 Ti-Maghemite L-75 Reduction of Fe-Ti oxides L-75

FE-0-MG0-TI02 SYSTEM L-79

Fe0-Fe203-Mg0 join L-80 Fe0-Mg0-Ti02(-Ti203) join L-80 Fe0-Fe203-Mg0-Ti02 join L-81

FE0-FE203-AL203 SYSTEM L-81

CR203-BEARING SYSTEMS L-82

Fe0-Fe203-Cr203 system L-82 MgAl20^-Mg2Ti0^-MgCr20^ system L-83 FeCr204-Fe304-FeAl20^ system L-84 REFERENCES L-84

Chapter 3. OXIDE MINERALS in METAMORPHIC ROCKS Douglas Rumble, III INTRODUCTION R- 1 MINERALOGY R- 1 Spinel solid solutions R- 1 Hematite-ilmenite solid solutions R- 3 Pseudobrookite solid solutions R- 6 Rutile and polymorphs R- 6 OXIDE MINERALS IN RELATION TO METAMORPHIC MINERAL ZONES R- 7 Metamorphic zones of low to intermediate pressure R- 9 ChXorite and biotite zones R- 9 Garnet and staurolite zones R- 9 Sillimanite zone R-10 Sillimanite-potash feldspar zone R-10 Chromian spinel composition in relation to metamorphic zones . R-10 High-temperature contact metamorphism R-ll High-pressure metamorphism R-ll PHASE PETROLOGY R-ll Element partitioning R-ll Oxide mineral equilibria R-12 Oxide-silicate mineral equilibria R-15 Deduction of conditions of metamorphism R-16 OXIDATION-REDUCTION PROCESSES IN METAMORPHISM R-19 REFERENCES R-20

Chapter 4. OXIDATION of OPAQUE MINERAL OXIDES in BASALTS Stephen E. Haggerty INTRODUCTION Hg- 1 OXIDATION PARAGENESIS Hg- 3 Primary oxide mineralogy Hg- 3 Oxidation of ulvbspinel-magnetite solid solutions Hg- 4 Trellis type Hg- 4 Composite types Hg- 8

(v) Sanduich type Hg-16 Oxidation of titanomagnetite-ilmenite intergrowths Hg-16 C4 stage Hg-17 C5 stage Hg-20 C6 stage Hg-21 C7 stage Hg-24 Oxidation of discrete primary ilmenite Hg-28 Ilmenite oxidation classification Hg-28 PHASE CHEMISTRY OF OXIDATION ASSEMBLAGES Hg-37 Introduction Hg-37 Titanomagnetite-ilmenite assemblages Hg-46 Ferrian ilmenite and ferrian rutile Hg-49 Titanohematite, rutile, and magnetite Hg-50 Pseudobrookite, titanohematite, magnetite and Al-magnesioferrite Hg-52 OXIDE SYSTEMATICS AND PHASE COMPATIBILITY RELATIONSHIPS Hg-55 Introduction Hg-55 Ilmenite systematics Hg-61 Titanomagnetite systematics Hg-61 Applications Hg-69 ASSOCIATED MINERAL OXIDATION Hg-74 Introduction Hg-74 Chromian spinel oxidation Hg-74 Olivine oxidation Hg-75 OXIDE DISTRIBUTIONS IN BASALT PROFILES Hg-78 Introduction Hg-78 Mean oxidation numbers Hg-79 Oxide distributions Hg-82 Mechanism of oxidation Hg-94 IMPLICATIONS FOR ROCK MAGNETISM AND OXIDE PETROGENESIS Hg-95 Introduction Hg-95 Oxidation Hg-96 Single cooling units Hg-98 SUMMARY AND CONCLUSIONS Hg-98

Chapter 5. OXIDE MINERALS in LUNAR ROCKS Ahmed El Goresy INTRODUCTION EG- 1 MINERALOGY EG- 1 Chromite-ulv8spinel series EG- 1 Ilmenite-geikielite series EG- 3 Armalcolite-anosovite series EG- 4 Rutile EG- 4 OXIDE RELATIONS IN DIFFERENT ROCK TYPES RECOVERED FROM THE MOON . . EG- 4 Opaque oxides in Ti02~poor basalts EG- 4 Spinels EG- 5 Cationic relationships and substitutions EG-14 Cr-Al substitutional trends EG-14 V-Cr and V-Al substitutional trends EG-17

(vi) Fe-Mg substitutional trends EG-19 Ti-(V+Cr+Al) substitutions EG-19 Opaque oxides in Ti02-rich basalts EG-24 Armaloolite relationships EG-24 Origin of ilmenite rims around armaloolite in olivine porphyritio basalts EG-25 Chemistry of armaloolite EG-30 Chromian ulv'dspinel EG-34 Ilmenite EG-35 Rutile EG-3 6 Opaque oxides in anorthositic rocks and highland breccias .... EG-36 Spinels EG-3 7 Ilmenite EG-37 Rutile EG-37 SUBSOLIDUS REACTIONS EG-38 Subsolidus reduction reactions in the lunar rocks EG-39 Nature of reducing agent in Apollo 17 basalts EG-42 REFERENCES EG-43

Chapter 6. OPAQUE OXIDE MINERALS in METEORITES Ahmed El Goresy INTRODUCTION EG-47 MINERALOGY EG-49 Spinel group minerals EG-49 Ilmenite-geikielite-pyrophanite series EG—56 Rutile EG-5 7 OXIDE ASSEMBLAGES IN VARIOUS METEORITE GROUPS EG-57 Chondrites EG-57 Spinels EG-5 9 Ilmenite EG-6 2 Achondrites EG-64 Ilmenite EG-6 5 Stony irons EG-65 Iron meteorites EG-67 REFERENCES EG-71

Chapter 7. The MANGANESE OXIDES - A BIBLIOGRAPHIC COMMENTARY J. Stephen Huebner INTRODUCTION SH- 1 Crystal structures and chemistry SH- 1 Tetravalent oxides SH- 1 Trivalent oxides SH- 2 "Spinel-type" oxides SH- 3 WUstite-type oxide SH- 4 Geologic occurrences SH- 4 Thermochemistry and phase relations SH- 6 Petrology of manganese oxides SH- 8 REFERENCES SH-11

(vii) Chapter 8. OPAQUE MINERAL OXIDES in TERRESTRIAL IGNEOUS ROCKS Stephen E. Haggerty GENERAL INTRODUCTION Hg-101 SYSTEMATIC MINERALOGY Hg-101 Nomenclature Hg-101 Spinel series Hg-101 Ilmenite series Hg-104 Pseudobrookite series Hg-104 TiOg polymorphs Hg-104 Exsolution Hg-104 Subsolidus reactions Hg-108 Oxide assemblages and textures Hg-108 Two-dimensional mineral morphology Hg-108 Chromian spinelss Hg-109 Ilmenite-hematitess Hg-118 Reactions involving ilmenite-hematitess Hg-119 UlvOspinel-magnetitess Hg-123 Titanomagnetite-pleonaste^s Hg-128 Magnetite-chronrite-hercymtess Hg-129 Reactions involving magnetite-ulvSspinelss Hg-129 Oxides derived from silicates Hg-135 PRIMARY OXIDE DISTRIBUTIONS Hg-140 Introduction Hg-140 Chromian spinel distributions Hg-142 Pseudobrookite distributions Hg-150 Ilmenite distributions Hg-152 Magnetite-ulvSspinel distributions Hg-158 Oxidites Hg-158

T AND fo2 VARIATIONS IN IGNEOUS ROCKS Hg-160 Introduction Hg-160 Extrusive suites Hg-160 Intrusive suites Hg-160 Magmatic ore deposits Hg-167 Data summary Hg-167 Experimental determinations of T and fQ2 Hg-169 Silica activity Hg-169 TABLES OF MINERALOGICAL, PETROLOGICAL, AND CHEMICAL PROPERTIES OF OPAQUE MINERAL OXIDES IN IGNEOUS ROCKS Hg-176 REFERENCES Hg-277

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