High-Temperature Metamorphism and Crustal Anatexis

This second volume in the new series produced by the Mineralogical Society is concerned with the study of rocks from the deep continental crust. It is, we hope, timely to summarize recent petrological advances contributing to this field of active interest. Based mainly on review papers read at a conference, the chapters have subsequently been revised and expanded, while the editors have produced an introductory overview as Chapter 1. The conference was the Winter Meeting of the Mineralogical Society on 15 December 1988, at wh ich Prof. R. C. Newton delivered the 20th Hallimond Lecture of the Society (which forms the basis of Ch. 7). The editors are grateful to all who contrib­ uted to the smooth running of the meeting at Kingston Polytechnic, and in the ensuing preparation of the volume: in particular, we sincerely thank all of the following for their labours as referees: A. J. Baker, L. M. Barron, M. J. Bickle, A. D. Chambers, J. D. Clemens, J. S. Daly, G. T. R. Droop, C. R. L. Friend, E. S. Grew, S. L. Harley, R. S. Harmon, N. B. W. Harris, B. Harte, T. J. B. Holland, N. F. C. Hudson, W. S. MacKenzie, W. Perkins, H. R. Rollinson, J. W. Sheraton, D. J. Waters, R. H. Worden and B. W. D. Yardley. John R.

1 An overview of diverse responses to diverse processes at high crustal temperatures.- 1.1 Introduction.- 1.2 Processes and materials.- 1.3 Mineral equilibria.- 1.4 Melting equilibria.- 1.5 Amount and mobilization of melt.- 1.6 Melt-restite interaction and retrograde evolution.- 1.7 Fluid movements.- 1.8 P-T-t paths and tectonic models.- References.- 2 Graphical analysis of P-T-X relations in granulite facies metapelites.- 2.1 Introduction.- 2.2 Phase relations in a simple system: MgO-Al2O3-SiO2 (MAS).- 2.3 The system FMAS.- 2.4 A multisystem in FMAS.- 2.5 Relationships between FMAS, MAS, and FAS.- 2.6 Variation of XMg along FMAS univariant boundaries.- 2.7 Chemical potential diagrams: P-µFeO.- 2.8 µFe2O3-µFeO diagrams.- 2.9 Curved reaction boundaries and P-T-XFe-Mg-Al relations in FMAS.- 2.10 Effects of % MathType!MTEF!2!1!+- % feaagCart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyyamaaBa % aaleaacaWGibWaaSbaaWqaaiaaikdaaeqaaSGaam4taaqabaGccaGG % SaGaamyyamaaBaaaleaacaWGdbGaam4tamaaBaaameaacaaIYaaabe % aaaSqabaaaaa!3DF7!$${a_{{H_2}O}},{a_{C{O_2}}}$$, and vapour-absent conditions on the FMAS granulite grid.- 2.11 Phase relations in silica-undersaturated pelites.- 2.12 Reactions involving biotite in KFMASH.- 2.13 Concluding remarks.- Acknowledgements.- References.- 3 A model for rates of disequilibrium melting during metamorphism.- 3.1 Introduction.- 3.2 Factors controlling melting rates.- 3.3 Experimental kinetic studies.- 3.4 Description and results of a model.- 3.5 Discussion.- Acknowledgements.- References.- Appendix 1.- 4 Formation and composition of H2O-undersaturated granitic melts.- 4.1 Introduction.- 4.2 The initiation of melting at lower-crustal P and T, and at a reduced level of H2O activity.- 4.3 Composition of H2O-undersaturated melts in the system Qz-Ab-Or-H2O-CO2.- 4.4 Amounts of the An component in partial granitic melts.- 4.5 Amounts of mafic components (Fe, Mg, Al) dissolved in granitic melts.- 4.6 Liquidus temperatures and minimum water contents of H2O-undersaturated haplogranitic melts.- 4.7 Amount of partial melts generated in fluid-absent conditions at given P, T, and water conten.- 4.8 Summary and conclusions.- References.- 5 Garnet porphyroblast-bearing leucosomes in metapelites: mechanisms, phase diagrams, and an example from Broken Hill, Australia.- 5.1 Introduction.- 5.2 Round Hill metapelites.- 5.3 Processes.- 5.4 Phase diagram considerations.- 5.5 Conclusions.- Acknowledgements.- References.- 6 Isotopic modification of the continental crust: implications for the use of isotope tracers in granite petrogenesis.- 6.1 Introduction.- 6.2 Geochemical evolution of silicic magmas.- 6.3 Anomalously low 87Sr/86Sr ratios in some crustally derived granitoids.- 6.4 Discussion and conclusions.- Acknowledgement.- References.- 7 Fluids and melting in the Archaean deep crust of southern India (Hallimond Lecture of the Mineralogical Society).- 7.1 Introduction.- 7.2 Melting relations of a model crust.- 7.3 Interpretation of Closepet-charnockite relations.- 7.4 Possible applications to other terrains.- Acknowledgements.- References.- 8 Fluid-rock interaction in the north-west Adirondack Mountains, New York State.- 8.1 Introduction.- 8.2 Early fluid-related events.- 8.3 Late fluid incursions.- 8.4 Discussion.- Acknowledgements.- References.- 9 Progressive reactions and melting in the Acadian metamorphic high of central Massachusetts and southwestern New Hampshire, USA.- 9.1 Introduction.- 9.2 P-T-t paths and metamorphic field gradients.- 9.3 Background and setting.- 9.4 The metamorphic zones of central Massachusetts.- 9.5 Crossing isograds and isotherms.- 9.6 Temperature versus TiO2 content of minerals.- 9.7 Prograde assemblages.- 9.8 Melting.- 9.9 Summary.- Acknowledgements.- References.- 10 Granulite facies metamorphism of metabasic and intermediate rocks in the Highland Series of Sri Lanka.- 10.1 Introduction: why Sri Lanka?.- 10.2 Previous and recent work.- 10.3 Rock types.- 10.4 Reaction textures.- 10.5 Mineral chemistry.- 10.6 Metamorphic conditions.- 10.7 Ti in amphiboles.- 10.8 P-T-t path.- 10.9 Discussion.- Acknowledgements.- References.- 11 Local, mid-crustal granulite facies metamorphism and melting: an example in the Mount Stafford area, central Australia.- 11.1 Introduction.- 11.2 What causes granulite facies metamorphism?.- 11.3 The Arunta Block.- 11.4 The Mount Stafford area.- 11.5 The structure of the Mount Stafford area.- 11.6 Metamorphic (M1) zones.- 11.7 Partial melting.- 11.8 Post-peak reactions.- 11.9 Chemical compositions of minerals.- 11.10 P-T grids for the mineral assemblages.- 11.11 P-T-t path.- 11.12 Peak-metamorphic temperatures.- 11.13 Peak-metamorphic pressure.- 11.14 Discussion.- 11.15 Conclusions.- Acknowledgements.- References.- 12 Archaean and Proterozoic high-grade terranes of East Antarctica (40–80°E): a case study of diversity in granulite facies metamorphism.- 12.1 Introduction and general considerations.- 12.2 The Napier Complex.- 12.3 The Vestfold Hills Block.- 12.4 The Lützow — Holm Bay Complex.- 12.5 Proterozoic overprinting in the Napier Complex and Napier relics within the Rayner Complex, Enderby Land.- 12.6 The Rayner Complex in Enderby Land.- 12.7 The Rayner Complex: Kemp Land and MacRobertson Land.- 12.8 The south-east Prydz Bay region.- 12.9 The Rauer Group.- 12.10 Discussion: tectonic models for granulite terranes and the evolution of the East Antarctic Shield.- Acknowledgements.- References.- 13 Prograde metamorphism, anatexis, and retrogression of the Scourian Complex, north-west Scotland.- 13.1 Introduction.- 13.2 Conditions of Badcallian metamorphism.- 13.3 Partial melting during granulite fades metamorphism.- 13.4 Partial melting in metabasic and metasedimentary lithologies.- 13.5 Partial melting in the tonalitic gneisses.- 13.6 Major and trace element constraints on melting.- 13.7 Causes of the Badcallian metamorphism.- 13.8 Causes of Inverian retrogression.- 13.9 Discussion and conclusions.- Acknowledgements.- References.