1. Ultramafic Rock Bodies Petrography - gabbroic & ultramafic rocksPetrography - gabbroic & ultramafic rocks Nature of plutonsNature of plutons Oceanic subalkaline associationsOceanic subalkaline associations Ophiolites (treated with basalts in GLY206)Ophiolites (treated with basalts in GLY206)

2. AMF Diagrams Initial compositionsInitial compositions Early iron enrichmentEarly iron enrichment Later alkali enrichmentLater alkali enrichment Tholeiitic vs. calc-alkali trendsTholeiitic vs. calc-alkali trends

3. Petrography of Gabbroic and Ultramafic Rocks GeneralGeneral FabricFabric –Phaneritic grain-size Slow sequential growthSlow sequential growth Hypidiomorphic granularHypidiomorphic granular

4. Mineralogy May be nearly monomineralicMay be nearly monomineralic PlagioclasePlagioclase An 85 to An 50An 85 to An 50 PyroxenePyroxene Ortho (Hypersthene)Ortho (Hypersthene) Clino (Augite to Pigeonite)Clino (Augite to Pigeonite) OlivineOlivine Fo 85 to Fo 30Fo 85 to Fo 30

5. Petrography of Gabbroic and Ultramafic Rocks ClassificationClassification Pl-Ol-Px diagramPl-Ol-Px diagram Olivine-Opx-CpxOlivine-Opx-Cpx AlterationAlteration Deuteric and hydrothermal alterationDeuteric and hydrothermal alteration SerpentineSerpentine Secondary iron oxideSecondary iron oxide Brucite & talcBrucite & talc

6. Nature of Plutons Dikes, sills, and plugsDikes, sills, and plugs Layered intrusionsLayered intrusions Slow shallow cooling of basaltic magmaSlow shallow cooling of basaltic magma

7. Cooling & Crystallization SillsSills Progressive fractionationProgressive fractionation Settling at bottomSettling at bottom Assimilation at topAssimilation at top Crystallization from marginsCrystallization from margins

8. Sequence of Crystallization OlivineOlivine ClinopyroxeneClinopyroxene PlagioclasePlagioclase Fe-Ti oxidesFe-Ti oxides ApatiteApatite

9. Form of Bodies SillsSills Example of Red Hill, TasmaniaExample of Red Hill, Tasmania Form and zonation of bodyForm and zonation of body

10. Stillwater Intrusion, Montana LayeringLayering Zonation of mineralsZonation of minerals

11. Skaergaard Intrusion, Greenland General form of the bodyGeneral form of the body Layering of the intrusionLayering of the intrusion Mineral zonation of layersMineral zonation of layers Hydrothermal alterationHydrothermal alteration