Ashworth Migmatites

1985
ISBN: 978-1-4613-2347-1
Verlag: Springer US
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 302 Seiten, eBook

Zielgruppe

Research

Autoren/Hrsg.

Ashworth, J. R.

Inhaltsverzeichnis

1 Introduction.- 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.- 2.1 Introduction.- 2.2 Experimental studies in the haplogranite system Qz-Or-Ab-H20.- 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.- 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.- 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.- 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.- 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.- 7.1 Introduction.- 7.2 Early migmatites.- 7.3 Late migmatites.- 7.4 Sutherland migmatites.- 7.5 Conclusions.- References.- 8 Fluid inclusions in migmatites.- 8.1 Introduction.- 8.2 Fluid inclusions in migmatites of Bamble, Norway.- 8.3 Fluid inclusions in the Front Range migmatites.- 8.4 Possible melt inclusions in migmatites.- 8.5 Discussion.- References.- Index of authors cited.