Feldspar Mineralogy

373 Pages·1983·161.178 MB·English

by  PH Ribbe, Ed.

REVIEWS In
MINERALOGY
(Formerly: "Short Course Notes")
Volume 2
SECOND EDITION
FELDSPAR MINERALOGY
P. H. Ribbe,
EDITOR and SERIES EDITOR
The Authors
Anne M. Hofmeister & George R. Rossman
Division of Geology and Planetary Science
California Institute of Technology
Pasadena, California 91125
v Herbert Kroll
Institut fur Mineralogie
Westfaf ische Wilhelrns- Universi tat
4400 Munster, West Germany
Paul H. Ribbe
Department of Geological Sciences
Virginia Polytechnic Institute & State University
Blacksburg, Virginia 24061
1/ Joseph V. Smith
Department of Geophysical Sciences
University of Chicago
Chicago, Illinois 60637
" David B. Stewart
United States Geological Survey
959 National Center
Reston, Virginia 22092
" Jan Tullis &,/ Richard A. Yund
Department of Geological Sciences
Brown University
Providence, Rhode Island 02912
MINERALOGICAL SOCIETY OF AMERICA
COPYRIGHT
Mineralogical Society of America
First edition 1975
Second edition 1983
PRINTED BY
BOOKCRAFTERS, Inc.
Chelsea, Michigan 48118
REVIEWS in MINERALOGY
(Formerly: "Short Course Notes")
ISSN0275-0279
Volume 2, Second Edition:
FELDSPAR MINERALOGY
ISBN0-939950-14-6
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Aditional copies of this volume as well as those
listed below may be obtained at moderate cost from-
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Volume
1 SULFIDE MINERALOGY, P.H. Ribbe, editor (1974) 284 p.
2 FELDSPAR MINERALOGY, P.H. Ribbe, editor (1975; revised 1983) 360 p.
3 OXIDE MINERALS, Douglas Rumble III, editor (1976) 502 p.
4 MINERALOGY and GEOLOGY of NATURAL ZEOLITES,
F.A. Mumption, editor (1977) 232 p.
5 ORTHOSILICATES, P.H. Ribbe, editor (1980; revised 1982) 450 p.
6 MARINE MINERALS, R.G. Burns, editor (1979) 380 p.
7 PYROXENES, C.T. Prewitt, editor (1980) 52~ p.
8 KINETICS of GEOCHEMICAL PROCESSES, A. C. Lasaga and
R.J. Kirkpatrick, editors (1981) 391 p.
9A AMPHIBOLES and OTHER HYDROUS PYRIBOLES - MINERALOGY,
D.R. Veblen, editor (1981) 372 p.
9B AMPHIBOLES: PETROLOGY and EXPERIMENTAL PHASE RELATIONS,
D.R. Veblen and P.H. Ribbe,edLtozs (1982} 390 p.
10 CHARACTERIZATION of METAMORPHISM through MINERAL EQUILIBRIA,
J.M. Ferry, editor (1982) 397 p.
11 CARBONATES, R.M. Reeder, editor (1983) In press
ii
FELDSPAR MINERALOGY
FOREWORD
TO THE SECOND EDITION
In October 1975 a Short Course on Feldspar Mineralogy was held at the
Hotel Utah, Salt Lake City, in conjunction with the annual meetings of the
Mineralogical Society of America. Richard A. Yund, David B. Stewart, Joseph
V. Smith and Paul H. Ribbe presented workshops on x-ray single-crystal and
powder diffraction methods and electron optical techniques as applied to the
study of feldspars and presented eight lectures, the substance of which became
the nine chapters of the first edition of Feldspar Mineralogy. That book was
published by the Mineralogical Society as the second volume of its series en-
titled "Short Course Notes".
In 1980 the M.S.A. renamed the series "Reviews in Mineralogy" to more
accurately reflect the scope and contents of the volumes, some of which __in-
cluding Volume 5 (1st and 2nd editions), this volume and a forthcoming one on
fluid inclusions --were written without presentation at a short course. Eleven
volumes are now available from the M.S.A. at reasonable cost (see p. ii).
Three years ago it was decided not to reprLnt Feldspar Mineralogy when its
second press run sold out. That was a mistake, because as this, the second edi-
tion, was slowly taking shape, no volume on feldspars has been available for
two years. Unfortunately the present revised volume was advertised and orders
were accepted, with resulting dissatisfaction of patrons. The series editor
accepts full responsibility for this; hopefully the updating, improvements,
and new contributions in this edition will in part compensate for the incon-
venience.
It will be noted by readers experienced with feldspars that there are many
new ideas appearing in Chapters 3, 4 and 5 that have neither received scrutiny
by review (other than ourselves) nor survived practical tests of time in the
research community. There is some danger in this, but the editor decided the
greater risk was to produce a review volume soon to be outdated.
Inevitably, given the different goals of individual authors in their
assigned topics, some repetition of material has occurred, although usually
with quite different emphases. Chapters· 1, 2, 9 and 10, in which plagioclase
structures and diffraction patterns and their Al,Si distributions, phase equi-
libria and exsolution textures are featured, are notable in this regard. The
editor has attempted to cross-reference these and as many other subjects
throughout the volume as feasible. This is a luxury not afforded in other
books of this series produced with a short course deadline, and it, together
with the detailed Table of Contents, compensates to some degree for the lack
of an index.
Paul H. Ribbe
Series Editor
Blacksburg, VA
April 30, 1983
iii
ACKNOWLEDGMENTS
Throughout this book repeated references are made to Smith (1974a,b);
these are Volumes 1 and 2 of Feldspap Minepals, an encyclopedic work written
by Joseph V. Smith and published by Springer-Verlag. We are particularly in-
debted to Drs. Konrad Springer and H. Wiebking for permission to reproduce
many figures free of charge. We also thank the editors and publishers of the
following journals and books for their permission to reprint figures:
The American Journal of Science The American Mineralogist
Bulletin de La socrece francaise d~ Hineraiogie et de Cristallographie
Chemical Geology Contributions to Mineralogy and Petrology
Geochimica et Cosmochimica Acta Journal of Geology
Mineralogical Journal, Japan Philosophical Magazine
Physics and Chemistry of Minerals Proceedings of the Japan Academy
Schweizerische Mineralogische und Petrographische Mitteilungen
The Feldspars Manchester University Press
Geochemical Transport and Kinetics Carnegie Institution
Rock-Forming Minerals Longmans
Electron Microscopy in Mineralogy Springer-Verlag
The editor (and hopefully this volume) benefitted greatly from numerous
stimulating discussions with David B. Stewart, some of which reached a high
pitch, none of which came to blows, and several of which produced some palpable
scientific progress. Stewart read and criticized many of the chapters. The
authors are grateful to numerous individual scientists for figures, for data
in advance of publication, and for encouragement and correction.
Margie Strickler and Ada Simmons are to be commended for perseverance
and great skill in typing the text and Sharon Chiang and her staff for excel-
lent draftsmanship. The editor's colleagues and the secretarial staff of the
Department of Geological Sciences at Virginia Polytechnic Institute and State
University are thanked for their patience with him during the long process of
writing, rewriting, editing and composing. Support of the University in pro-
viding facilities (and salary!) is gratefully acknowledged, as are his A.G.D.
friends at the M.S.A. office who suffered much abuse over back-orders for this
edition of Feldspar Mineralogy, nearly two years overdue.
SELECTED REFERENCE WORKS
The following is a list of useful reference works on feldspar mineralogy pub-
lished in recent years:
Feldspar Minerals, 1. Crystal Structure and Physical Properties,
Feldspar Minerals, 2. Chemical and Textural Properties. By Joseph V. Smith (1974), Springer-
Verlag: NewYork. 627 and 690 pp.
The Feldspars, Proceedings of a NATOAdvanced Study Institute, Manchester, England. 1972.
Edited by W. S. MacKenzie and J. zussman (1974), Manchester University Press: Manchester.
717 pp.
Les Solutions Solides en Min~ralogie, CoLl.oque International du C.N.R.S. No. 234, Orleans, 1974.
Edited by G. Sabatier (1974). euu: Soc. franc. Min~raZ. cri.etial.loqv- 97,89-404.
Electron Microscopy in Mineralogy. Edited by H.-R. Wenk and G. Thomas (1976). Springer-Verlag:
Berlin. 525 pp.
Thema PeLdspate, 1967. Sohuei zeri-eche Mineralogische und Petrographische Mitteilungen 47/1,
398 pp•
Rock-Forming Minerals, 4. Framework Silicates. By W. A. Deer, R. A. Howie, and J. Zussman.
Longmans: London. pp. 1-178.
Proceedings of the NATOAdvanced Study Institute of Feldspars, Olso, 1962. Edited by O.H.J.
Christie (1962). Norsk Geologisk Tidssk:rift 42/2, 606 pp.
The Feldspars --Phase Relations. Optical Properties, and Geological Distribution. By A. S.
Marfunin. Translated from the 1962 Russian edition, 1966. Israel Prog. Sci. Translations:
Jerusalem. 317 pp,
Proceedings of a NATOAdvanced Study Institute on Feldspars and Feldspathoids, Rennes, France.
1983. Edited by W. L. Brown, untitled at press time.
iv
FELDSPAR MINERALOGY
TABLE of CONTENTS
Page
COPYRIGHT; LIST OF PUBLICATIONS ii
FOREWORD TO THE SECOND EDITION iii
ACKNOWLEDGMENTS; SELECTED REFERENCE WORKS iv
CHAPTER 1. P.H. RIBBE
The CHEMISTRY, STRUCTURE and NOMENCLATURE of FELDSPARS
INTRODUCTION
1
TOPOLOGY OF THE FELDSPAR TETRAHEDRAL FRAMEWORK 2
The a-axis projection
3
The e*-axis projection
6
The b-axis projection
6
Idealized cell parameters
9
PATTERNS OF ALUMINUM, SILICON ORDER-DISORDER:
NOMENCLATURE BASED ON STRUCTURE AND CHEMISTRY 9
Alkali (Na,K) feldspars with Al:Si = 1:3 and e ~ 7 K 9
Ca- and Ba-feldspars with Al:Si = 2:2 and e ~ 14 K 12
I2/c eelsian 14
pi anorthite 14
Ii anorthite 16
Summary of feldspar site nomenclature 17
Antiphase domains and the Ii average structure 19
CHAPTER 2. P.H. RIBBE
ALUMINUM-SILICON ORDER in FELDSPARS:
DOMAIN TEXTURES and DIFFRACTION PATTERNS
INTRODUCTION 21
SEQUENCES OF Al,Si ORDER IN ALKALI FELDSPARS . . . . . . . . . . . .. 22
Ordering in K-feldspars involving a monoclinic+triclinic inversion 22
Development of polysynthetie tioinein mieroeline 24
Untlilinnedor simple-tlilinnedmieroeline 28
One-step or tiao-etiepordering? 28
Temperature seale for the sanidine+mieroeline inversion 30
Ordering in triclinic alkali feldspars 30
Potassium feldspar 30
Sodium feldspar 30
Page
CHAPTER 2,continued
SINGLE-CRYSTAL DIFFRACTION PATTERNS OF PLAGIOCLASES • . . • • . . . •. 31
X-ray techniques 32
The preeession method 32
The oseillation method 32
Summary of plagioclase diffraction patterns 33
SEQUENCES OF Al,Si ORDERING IN PLAGIOCLASES 39
Ordering in sodic plagioclases 40
Albite 40
Peristerites 41
Average structure models of plagioclase 42
Ordering in calcic plagioclases 44
Anorthite 44
Bytownite 48
High plagioelases 48
Huttenloeher intergrowths 49
Ordering in plagioclases of intermediate composition 50
oliqocl.aee 50
'e'-plagioelase 51
B~ggild intergrowths 54
SUMMARY . 54
CHAPTER 3. H. KROLL & P.H. RIBBE
LATTICE PARAMETERS, COMPOSITION and Al,Si ORDER in ALKALI FELDSPARS
INTRODUCTION 57
TETRAHEDRAL SIZE AND Al,Si DISTRIBUTION 58
A linear model 58
A new model 67
Correction of bonding effects 69
LATTICE PARAMETERS OF ALKALI FELDSPARS 70
Alkali exchange series 70
Cell volume and the a dimension 74
The band e cell dimensions 75
THE b-e PLOTS TO DERIVE (tlo + tIm) 77
THE a*-y* PLOT TO DERIVE (tlo - tIm) 79
STRAINED FELDSPARS • • . • . . • • • 81
THE [1101 METHOD FOR DETERMINING Al,Si DISTRIBUTIONS 84
Basis of the [110] method 85
The [110] method for alkali feldspars 87
Diagrams to estimate tlo and (tlo - tIm) 89
vi
CHAPTER 3,continued
Page
ESTIMATION OF ERRORS 93
OTHER DETERMINATIVE METHODS 94
PETROLOGIC APPLICATIONS 96
Ordering paths 96
Suggested convention for plotting Al,Si distribution data 98
CHAPTER 4. H. KROLL
LATTICE PARAMETERS and DETERMINATIVE METHODS
for PLAGIOCLASE and TERNARY FELDSPARS
INTRODUCTION 101
LATTICE PARAMETER VARIATION 103
High plagioclases 103
Low plagioclases 106
Thermal expansion 107
THE [110] METHOD FOR PLAGIOCLASE FELDSPARS 110
••••••••• e.••
Diagrams to estimate tlo and (tlo - <tIm» 110
Estimation of errors 113
THE [110] METHOD FOR TERNARY FELDSPARS 113
THE 6131 METHOD AND THE.Y METHOD 117
A GUIDE TO INDEXING PLAGIOCLASE POWDER PATTERNS 119
CHAPTER 5. D.B. STEWART & P.H. RIBBE
OPTICAL PROPERTIES of FELDSPARS
INTRODUCTION
121
ALKALI FELDSPARS: OPTIC AXIAL ANGLES 122
Optic axial angle, 2V an indicator of (tlo + tIm) 123
x
2Vxfor the low microcl ine +hiqh. sanidine series 123
2Vxfor the low albite +analbite series 125
2Vxfor the low albite +low microcl.ine series 127
2Vxfor the high albite (or analbite) +hi.qh.sanidine series 127
The b-c plot eontoured for 2Vx 127
Effects of exsolution and strained composites on 2Vx 130
2Vx as evidence of highest structural state 130
ALKALI FELDSPARS: EXTINCTION ANGLES ...•..
131
Extinction angle on (001) 131
Extinction angle on (010) 132
Conclusions
133
PLAGIOCLASE . • .
134
vii
CHAPTER 5,continued
Page
Refractive indices 136
Optic axial angle, 2Vx 137
Optic orientation and extinction angles 137
CHAPTER 6. R.A. YUND & J. TULLIS
SUBSOLIDUS PHASE RELATIONS in the ALKALI FELDSPARS
with Emphasis on Coherent Phases
INTRODUCTION 141
DISPLACIVE AND ORDER-DISORDER RELATIONS 141
Monalbite-analbite 143
Stability of ordered phases 144
STRAIN-FREE SOLVUS 145
Sanidine-high albite 145
Low microcline-low albite 148
COHERENT EXSOLUTION 149
Introduction 149
Coherent exsolution lamellae 150
Identification of coherent lamellae 152
Orientation of the lamellae 153
Composition of the coherent lamellae 155
THE COHERENT SOLVUS 159
General relations 159
Application to alkali feldspars 162
Maximum mieroeline-low albite eoherent solvus 163
Sanidine-high albite eoherent solvus 164
APPENDIX: CRYSTAL ELASTICITY AND ELASTIC CONSTANTS FOR FELDSPARS . . . 170
CHAPTER 7. R.A. YUND
MICROSTRUCTURE, KINETICS and MECHANISMS of ALKALI FELDSPAR EXSOLUTION
INTRODUCTION 177
EXSOLUTION MECHANISMS 177
Nucleation 177
Spinodal decomposition 178
EXSOLUTION MICROSTRUCTURE . 182
EXPERIMENTAL STUDY OF ALKALI FELDSPAR EXSOLUTION 184
Development of initial microstructure 184
viii
CHAPTER 7,continued
Page
Coarsening of the lamellae microstructures 189
MINERALOGICAL APPLICATIONS 191
Cryptoperthites 191
Nonlamellar cryptoperthites 193
Coarse perthites 195
CHAPTER 8. R.A. YUND
DIFFUSION in FELDSPARS
INTRODUCTION 203
DIFFUSION COEFFICIENTS 203
DETERMINATION OF DIFFUSION COEFFICIENTS 205
EXPERIMENTAL RESULTS 208
Anisotropy of diffusion in feldspar 208
Effect of hydrostatic pressure and water on alkali diffusion 209
Alkali diffusion coefficients 210
Rb, Sr, and Ca diffusion 213
Argon diffusion 214
Silicon and aluminum diffusion 214
Oxygen diffusion 215
Mechanism of ionic diffusion in feldspars 218
APPLICATION OF THE DIFFUSION DATA 220
CHAPTER 9. J.V. SMITH
PHASE EQUILIBRIA of PLAGIOCLASE
INTRODUCTION 223
MELTING RELATIONS 223
ANORTHITE 224
ALBITE 225
FIELDS OF HOMOGENEOUS PLAGIOCLASE 227
'e'-PLAGIOCLASE 229
PERISTERITE . . 233
HUTTENLOCHER INTERGROWTH 235
B¢GGILD INTERGROWTH . • . 236
OTHER ASSEMBLAGES IN METAMORPHIC ROCKS 237
EXPERIMENTAL SUBSOLIDUS PHASE EQUILIBRIA 238
SUMMARY • • • • • • • • 239
ix
Page
CHAPTER 10. P.H. RIBBE
EXSOLUTION TEXTURES in TERNARY and PLAGIOCLASE FELDSPARS;
INTERFERENCE COLORS
INTRODUCTION 241
EXSOLUTION IN THE TERNARY FELDSPARS 242
Mesoperthites 242
Antiperthites 246
Andesine antiperthite from a metamorphosed anorthosite 248
"Moonstone" from Labrador 249
EXSOLUTION IN PLAGIOCLASE FELDSPARS 251
Peristerites 251
Phase relations 251
Textures 251
Comparisons of eoexisting phases 254
Huttenlocher intergrowths 257
B~ggild intergrowths 261
INTERFERENCE COLORS 266
SUMMARY ... 270
CHAPTER 11. A.M. HOFMEISTER & G.R. ROSSMAN
COLOR in FELDSPARS
INTRODUCTION 271
COLORLESS FELDSPAR 271
YELLOW FELDSPAR 271
AMAZONITE 272
Blue to green potassium feldspar 272
Blue plagioclase 276
SMOKY FELDSPAR 277
COLORS FROM INCLUSIONS 277
Red schiller and red-clouded feldspars 277
Black-clouded feldspars 279
SUNSTONES FROM LAKE COUNTY, OREGON 279
CHAPTER 12. J.V. SMITH
SOME CHEMICAL PROPERTIES of FELDSPARS
INTRODUCTION 281
Analytical methods 282
Ion microprobe analyses 282
Summary 283
x