ALBERT

Note: 1 Introduction J.R. Ashworth 1.1 Scope of the book 1.2 Definitions 1.3 Migmatites and granites 1.4 Melt-absent migmatization 1.5 Compositions of anatectic leucosomes 1.6 Textures and structures as possible indicators of melt presence 1.7 Estimation of P-T-aₕ₂ₒ conditions 1.8 The Granulite Facies 1.9 Mineral compositions in leucosome and melanosome: the plagioclase problem 1.10 Open and closed systems 1.11 Conclusions References 2 The significance of experimental studies for the formation of migmatites W. Johannes 2.1 Introduction 2.2 Experimental studies in the haplogranite system Qz-Or-Ab-H₂O 2.3 Experimental studies in the tonalite system Qz-Ab-An-H₂O 2.4 Experimental studies in the granite system Qz-Or-Ab-An-H₂O 2.5 Plagioclase compositions: observations in nature, experimental findings and conclusions 2.6 Suggestions for future research References 3 Phase equilibria in partial melting of pelitic rocks James A. Grant 3.1 Introduction 3.2 Subsolidus phase equilibria and experimental data 3.3 Partial melting 3.4 Melting at Pₕ₂ₒ = Pₜₒₜₐₗ 3.5 Melting at Pₕ₂ₒ 〈 Pₜₒₜₐₗ 3.6 Vapour-absent melting 3.7 Internal and external control of intensive variables 3.8 Paths through time and space 3.9 Separation of solid, liquid and vapour 3.10 Summary liquidus relations 3.11 Conclusions References 4 Mass balance in migmatites Sakiko N. Olsen 4.1 Introduction 4.2 Baltimore Gneiss and Front Range migmatites 4.3 Mass-balance calculations: methods and assumptions 4.4 Mass-balance calculations: results 4.5 Littleton Formation migmatites 4.6 Discussion References 5 Textures J.R. Ashworth and E.L. McLellan 5.1 Introduction 5.2 Grain size 5.3 Textures attributed to crystallization from a melt 5.4 Grain shape 5.5 Grain orientation (petrofabric) 5.6 Grain contact relations 5.7 Conclusions References 6 Migmatite occurrences in New England Robert J. Tracy 6.1 Introduction 6.2 Tectonic evolution of New England 6.3 Grenville massifs of western New England 6.4 Ordovician migmatites in the western high grade belt 6.5 Migmatites of the eastern Acadian metamorphic high 6.6 Avalonian terrains overprinted in the Alleghenian 6.7 Summary References 7 Migmatites in the Moines David Barr 7.1 Introduction 7.2 Early migmatites 7.3 Late migmatites 7.4 Sutherland migmatites 7.5 Conclusions References 8 Fluid inclusions in migmatites J. Touret and Sakiko N. Olsen 8.1 Introduction 8.2 Fluid inclusions in migmatites of Bamble, Norway 8.3 Fluid inclusions in the Front Range migmatites

Note: 1 The nature, occurrence and geological significance of fluid inclusions 1.1 Introduction 1.1.1 Occurrence and distribution 1.1.2 Abundance and distribution in single crystals 1.1.3 The manifestation of inclusions in minerals 1.1.4 Inclusion morphologies 1.2 Paragenetic classification 1.3 Sorby's early work on homogeneous and heterogeneous trapping 1.4 Variations in fluid inclusion contents 1.5 Fluid inclusions as representative portions of geological fluids 1.5.1 Bulk leakage 1.5.2 Leakage through diffusion 1.5.3' Representative trapping 1.6 Changes after trapping 1.6.1 Re-equilibration of the inclusion walls and necking-down 1.6.2 Migration of inclusions in a thermal gradient 1.7 Geological significance of fluid inclusions 1.7.1 Composition of fluids 1.7.2 Geothermometry and geobarometry 1.7.3 Patterns of fluid flow 1.7.4 Fluid inclusion studies in mineral exploration 1.7.5 Fluid inclusion studies in oil exploration 1.7.6 Other applications 1.8 Concluding remarks 2 Sample selection and preparation for microscope examination 2.1 Introduction 2.2 Choice of material for study 2.2.1 Hydrothermal veins 2.2.2 Igneous rocks 2.2.3 Medium- to high-grade metamorphic rocks 2.2.4 Sedimentary rocks 2.3 Grain mounts 2.3.1 Preparation 2.3.2 Immersion oils 2.3.3 Manipulation of grains 2.4 Cleavage fragments for optical study 2.5 Preparation of polished wafers for thermometric analysis 2.5.1 Stage 1: sawing and grinding 2.5.2 Stage 2: polishing 2.5.3 Stage 3: reverse mounting 2.5.4 Handling difficult samples 2.5.5 Storage of specimens 2.5.6 Summary of basic requirements for fluid inclusion wafer preparation 3 Optical examination 3.1 Introduction 3.2 Optical requirements 3.3 Recognition and location of fluid inclusions 3.4 Recognition of phases within inclusions 3.4.1 Daughter minerals 3.4.2 Compressed gases 3.4.3 Hydrocarbon liquids 3.4.4 Glass 3.5 Recognition of necking-down, leakage and natural decrepitation 3.5.1 Problems of heterogeneous trapping and metastability 3.6 Classification of inclusions following optical study 3.7 Phase proportions in individual fluid inclusions 3.7.1 Degree of fill (F) and calculation of overall density for two-phase aqueous (L + V) inclusions 3.7.2 Calculation of overall density and salinity for three-phase aqueous (L + V + S) inclusions 3.7.3 Estimation of phase proportions 3.8 Other microscope techniques 3.8.1 Opening inclusions under the microscope 3.8.2 Ultraviolet (UV) microscopy 3.8.3 Infrared (IR) microscopy 3.8.4 Scanning electron microscopy (SEM) 3.9 Summary of observations during optical examination 4 Basic principles of thermometric analysis 4.1 Introduction 4.2 Heating 4.2.1 Liquid-vapour homogenization in two-phase (L + V) aqueous inclusions 4.2.2 Dissolution of daughter minerals 4.2.3 Homogenization of immiscible H₂O-CO₂ liquids 4.3 Freezing 4.3.1 Aqueous H₂O-salt systems 4.3.2 Non-aqueous CO₂-CH₄ -N₂ systems 4.3.3 Mixed H₂O-salt-CO₂ systems 5 Heating-freezing stages 5.1 Availability 5.1.1 Introduction 5.1.2 Chaixmeca stage 5.1.3 Linkam TH 600 stage 5.1.4 Reynolds stage 5.1.5 Additional considerations 5.2 Installation and calibration 5.2.1 Heating 5.2.2 Freezing 5.2.3 Alternative cryogenic baths 5.2.4 Calibration of the stage 6 Practical aspects of thermometric analysis 6.1 Introduction 6.2 Freezing 6.2.1 Aqueous H₂O-salt inclusions 6.2.2 Non-aqueous CO₂-CH₄-N₂ inclusions 6.2.3 Mixed H₂O-NaCl-CO₂ inclusions 6.3 Heating 6.3.1 Liquid-vapour homogenization 6.3.2 Dissolution of daughter minerals 6.3.3 Homogenization of H₂O-CO₂ inclusions 7 Presentation and interpretation of thermometric data 7.1 Introduction 7.2 Assessment of results for individual inclusions 7.2.1 Accuracy and precision 7.2.2 Data and presentation 7.3 Measurements and more measurements 7.4 Presentation of data 7.5 Interpretation of data 7.5.1 Recognition of discrete populations 7.5.2 Continuous variation 7.5.3 Further considerations of boiling, liquid immiscibility and halite-bearing inclusions 7.6 Estimation of pressure and trapping conditions 7.6.1 Methods for calculating fluid pressures from fluid inclusion data 7.6.2 Estimation of depth of trapping 8 The chemical analysis of fluid inclusions—theoretical considerations 8.1 Introduction 8.2 The crush-leach method 8.2.1 Introduction 8.2.2 Cation analysis 8.2.3 Anion analysis 8.2.4 Other considerations 8.3 Volatiles—bulk analysis 8.4 The ICP-linked decrepitation technique 8.5 Identification of solid phases by X-ray methods 8.5.1 Introduction 8.5.2 X-ray diffraction 8.5.3 Scanning electron microscopy (SEM) 8.5.4 Other solid phases 8.6 The microanalysis of individual inclusions 8.6.1 Introduction 8.6.2 Laser excited Raman spectroscopy 8.6.3 Laser beam ablation 8.6.4 Other techniques 8.7 Neutron activation analysis (NAA) 8.8 Isotopic analysis 9 The chemical analysis of fluid inclusions—practical considerations 9.1 Introduction 9.2 Crush-leach analysis for non-volatile components 9.2.1 Sample selection 9.2.2 Sample preparation 9.2.3 Analysis 9.2.4 Results 9.3 Decrepitation and the analysis of non-volatile constituents 9.3.1 Introduction 9.3.2 Sample selection 9.3.3 Sample preparation 9.3.4 Analysis 9.3.5 Results 9.4 The analysis of volatile constituents 9.4.1 Sample selection 9.4.2 Sample preparation 9.4.3 Analysis 9.4.4 Data obtained 9.5 Stable isotopic analysis 9.5.1 Sample selection 9.5.2 Sample preparation 9.5.3 Analysis 9.5.4 Results 9.6 Scanning electron microscopy and the analysis of solid phases 9.6.1 Preparation of sample 9.6.2 Instrument operation 9.6.3 Interpretation 10 Future trends in fluid inclusion studies 10.1 Importance of fluid processes in the Earth's crust 10.2 Developments in methodology 10.2.1 Analysis of individual inclusions 10.2.2 Bulk analysis of several inclusion populations 10.3 Theoretical considerations on the PVTX properties of fluids 10.4 Future applications 10.4.1 Deep crustal processes 10.4.2 Diagenesis and fluids in sedimentary basins 10.4.3 Hydrocarbon and mineral exploration 10.4.4 Tectonics 10.5 Summary Appendix I Some UK suppliers of equipment and consumables for the preparation of fluid inclusion polished wafers Appendix II Examples of standard charts for visually estimating the degree of fill (F) in two-phase inclusions Appendix III Main manufacturers/suppliers of optical equipment and heating-freezing stages Appendix IV Some suppliers of substances recommended for the temperature calibration of heating-freezing stages Appendix V Materials and equipment for routine crush-leach analysis References Index