Amphiboles: crystal chemistry, occurrence and health issues / ed. by Hawthorne F.C., Oberti R., Ventura G.D., Mottana A. - Washington, DC: Mineralogical Society of America, 2007. - 278 p. - (Reviews in mineralogy and geochemistry; Vol. 67). - ISSN 1529-6466; ISBN 978-0-939950-79-9  Место хранения:   09 | Институт геохимии им. А.П.Виноградова СО РАН | Иркутск | Библиотека

Оглавление / Contents

1 Amphiboles: Crystal Chemistry Frank C. Hawthorne, Roberta Oberti INTRODUCTION .................................................... 1 CHEMICAL FORMULA ................................................ 1 SOME ASPECTS OF CHEMICAL ANALYSIS ............................... 1 Chemical composition ........................................ 1 Summary ..................................................... 6 CALCULATION OF THE CHEMICAL FORMULA ............................. 7 24 (O, OH, F, CI) ........................................... 7 23 (O) ...................................................... 8 13 cations .................................................. 8 15 cations .................................................. 8 16 cations .................................................. 8 Summary ..................................................... 8 AMPHIBOLES: CRYSTAL STRUCTURE ................................... 8 Space groups ................................................ 9 Cell dimensions ............................................. 9 Site nomenclature ........................................... 9 The C2m amphibole structure ................................ 10 The P2l/m amphibole structure .............................. 12 The P2/a amphibole structure ............................... 12 The Pnma amphibole structure ............................... 12 The Pnmn amphibole structure ............................... 14 The Cl amphibole structure ................................. 17 STACKING SEQUENCES AND SPACE GROUPS ............................ 18 BOND LENGTHS AND BOND VALENCES IN [4]Al-FREE AMPHIBOLES ......... 19 THE DOUBLE-CHAIN OF TETRAHEDRA IN [4]Al AMPHIBOLES .............. 19 Variation in <T-O> bondlengths in C2/m amphiboles .......... 21 Variation in <T-O> bondlengths in Pnma amphiboles .......... 25 THE STEREOCHEMISTRY OF THE STRIP OF OCTAHEDRA .................. 27 The C2/m amphiboles: variation in mean bondlengths ......... 27 The Pnma amphiboles with B(Mg,Fe,Mn): variation in mean bondlengths .............................................. 30 The Pnma amphiboles with BLi: variation in mean bondlengths .............................................. 32 THE STEREOCHEMISTRY OF THE M(4) SITE ........................... 34 The calcic, sodic-calcic and sodic amphiboles .............. 35 Amphiboles with small В cations (magnesium-iron-manganese- lithium, magnesium-sodium and lithium-sodium) ............ 36 The C2/m amphiboles: variation in <M(4)-0> bondlengths ..... 36 The Pnma amphiboles: variation in <M/4-0> bondlengths ...... 36 THE STEREOCHEMISTRY OF THE A SITE .............................. 37 The C2/m amphiboles ........................................ 37 The P2/a amphibole ......................................... 40 The Pnma amphiboles ........................................ 40 The Pnmn amphiboles ........................................ 41 THE STEREOCHEMISTRY OF THE O(3) SITE ........................... 41 The C2/m amphiboles ........................................ 41 UNIT-CELL PARAMETERS AND COMPOSITION IN C2/m AMPHIBOLES ........ 42 SUMMARY ........................................................ 46 ACKNOWLEDGMENTS ................................................ 46 REFERENCES ..................................................... 47 APPENDIX 1: CRYSTAL-STRUCTURE REFINEMENTS OF AMPHIBOLE ......... 51 2 Classification of the Amphiboles Frank С Hawthorne, Roberta Oberti INTRODUCTION ................................................... 55 THE CURRENT CLASSIFICATION SCHEMES ............................. 55 HAND-SPECIMEN (FIELD) CLASSIFICATION OF AMPHIBOLES ............. 55 AMPHIBOLE CLASSIFICATION BY CHEMICAL FORMULA ................... 56 Prefixes ................................................... 56 Adjectival modifiers ....................................... 57 THE CURRENT CLASSIFICATION SCHEME (LEAKE ET AL. 1997, 2003) .... 57 The magnesium-iron-manganese-lithium amphiboles ............ 58 The calcic amphiboles ...................................... 58 The sodic-calcic amphiboles ................................ 58 The sodic amphiboles ....................................... 62 The sodium-calcium-magnesium-iron-manganese-lithium amphiboles ............................................... 62 Named amphiboles ........................................... 62 SIGNIFICANT ISSUES INVOLVED IN THE CLASSIFICATION OF AMPHIBOLES ................................................... 62 The role of Fe, (OH) and Li ................................ 64 Root names ................................................. 66 More on root names ......................................... 66 Criteria for the recognition of distinct species ........... 67 Prefixes ................................................... 67 Synthetic amphiboles ....................................... 68 THE PRINCIPAL VARIABLES USED IN THE CLASSIFICATION PROCEDURE ... 68 The T cations .............................................. 69 The W anions ............................................... 69 The В cations .............................................. 69 The A and С cations ........................................ 72 NEW SCHEMES FOR THE CLASSIFICATION OF AMPHIBOLES ............... 73 AMPHIBOLES WITH (OH,F,Cl) DOMINANT AT W ........................ 73 The magnesium-iron-manganese amphiboles .................... 73 The calcium amphiboles ..................................... 74 The sodium-calcium amphiboles .............................. 77 The sodium amphiboles ...................................... 78 The lithium amphiboles ..................................... 79 The sodium-magnesium-iron-manganese amphiboles ............. 79 AMPHIBOLES WITH O2- DOMINANT AT W .............................. 80 MAJOR DIFFERENCES BETWEEN THE CURRENT CLASSIFICATION AND SCHEMES 1 AND 2 .............................................. 80 THE TWO SCHEMES: FOR AND AGAINST ............................... 82 Recognition of the sodium-calcium and lithium- (magnesium-iron-manganese) groups ........................ 82 Retention versus removal of intermediate amphibole compositions ............................................. 82 SUMMARY ........................................................ 82 ACKNOWLEDGMENTS ................................................ 83 REFERENCES ..................................................... 83 APPENDIX I: REJECTED, REDEFINED AND RENAMED END-MEMBERS ........ 85 3 New Amphibole Compositions: Natural and Synthetic Roberta Oberti, Giancarlo Delia Ventura, Fernando Cámara INTRODUCTION ................................................... 89 NEW NATURAL-AMPHIBOLES COMPOSITIONS ............................ 89 Sadanagaites: how much TAl can occur in the amphibole structure? ............................................... 90 Fluorocannilloite and joesmithite: constraints for divalent cations at the A site ........................... 95 Li in amphiboles: clinoholmquistites, leakeites and sodic-pedrizites ......................................... 96 Other amphiboles with nearly equal amounts of large (Na, Ca) and small (Li, Mg, Mn, Fe) В cations: composition and symmetry ................................ 101 Anhydrous sodic amphiboles: ungarettiite, obertiite, dellaventuraite ......................................... 102 NEW COMPOSITIONS FOR SYNTHETIC AMPHIBOLES ..................... 104 Synthetic amphiboles with cations other than Si and Al at the T sites .......................................... 104 Synthetic amphiboles with uncommon С cations .............. 110 Synthetic amphiboles with uncommon В cations .............. 112 Synthetic amphiboles with uncommon A cations .............. 114 Common and uncommon W anions .............................. 116 Synthesis of amphiboles in the system Na2O-Li2O-MgO-SiO2-H2O-HF (LNMSH) ........................ 116 CONCLUDING REMARKS ............................................ 117 ACKNOWLEDGMENTS ............................................... 117 REFERENCES .................................................... 117 Long-Range Order in Amphiboles Roberta Oberti, Frank C. Hawthorne, Elio Cannillo, Fernando Camara INTRODUCTION .................................................. 125 METHODS OF DERIVING SITE POPULATIONS .......................... 125 Single-crystal Structure REFinement ....................... 125 Mossbauer spectroscopy .................................... 129 Infrared spectroscopy ..................................... 131 Other spectroscopic methods ............................... 134 SITE PREFERENCES OF THE MOST COMMON CATIONS ................... 134 Aluminum .................................................. 134 Beryllium ................................................. 140 Boron ..................................................... 141 Calcium ................................................... 141 Cobalt and nickel ......................................... 141 Chromium, vanadium, scandium and indium ................... 141 Gallium ................................................... 142 Germanium ................................................. 143 Ferrous iron .............................................. 143 Ferric iron ............................................... 146 Lithium ................................................... 148 Magnesium ................................................. 151 Manganese ................................................. 151 Potassium ................................................. 152 Sodium .................................................... 152 Strontium ................................................. 152 Titanium .................................................. 152 Zinc ...................................................... 154 Zirconium ................................................. 154 ANION INCORPORATION IN AMPHIBOLES ............................. 155 Chlorine .................................................. 155 Fluorine .................................................. 156 Hydrogen (as OH-) ......................................... 157 THE OXO COMPONENT: A DETAILED DISCUSSION ...................... 157 HYDROGEN IN EXCESS OF 2.0 APFU ................................ 162 FACTORS AFFECTING ORDERING OF CATIONS IN THE AMPHIBOLE STRUCTURE ................................................. 163 ACKNOWLEDGMENTS ............................................... 164 REFERENCES .................................................... 164 5 Short-Range Order in Amphiboles Frank C. Hawthorne, Giancarlo Delia Ventura INTRODUCTION .................................................. 173 LONG-RANGE ORDER .............................................. 173 SHORT-RANGE ORDER ............................................. 173 BOND-VALENCE ASPECTS OF SRO ................................... 175 SRO of heterovalent versus homovalent cations and anions .................................................. 176 (OH) AS A PROBE OF LOCAL ORDER IN AMPHIBOLE ................... 176 Mg-Fe2+ order-disorder over M( 1) and M(3) and its effect on the infrared spectrum ................................ 177 M2+-M3+ order-disorder over M(1) and M(3) and its effect on the infrared spectrum ................................ 177 NEXT-NEAREST NEIGHBOR EFFECTS: SRO OF HETEROVALENT-CATIONS IN TREMOLITE ................................................ 178 Infrared absorption in related amphiboles ................. 179 The effect of next-nearest-neighbor (NNN) cations ......... 180 Derivation of patterns of SRO ............................. 181 SRO of heterovalent cations in tremolite(56): application of bond-valence theory ...................... 181 NEAREST- AND NEXT-NEAREST-NEIGHBOR EFFECTS .................... 182 Nearest-neighbor sites: configuration symbols and atom arrangements ............................................ 182 NNN sites: the T sites .................................... 183 NNN sites: the M sites .................................... 183 The number of possible short-range arrangements of cations ................................................. 184 SHORT-RANGE ORDER AND SHORT-RANGE DISORDER .................... 184 SPECTRAL VARIATION IN THE INFRARED SPECTRA OF AMPHIBOLES ...... 185 Peak width and band width ................................. 185 Band position (energy) as a function of composition ....... 185 Resolution in infrared spectra ............................ 186 SHORT-RANGE DISORDER OF DIVALENT В CATIONS IN TREMOLITE ....... 187 The infrared spectrum of synthetic tremolite .............. 188 SRO IN RICHTERITE-PARGASITE SOLID-SOLUTIONS ................... 190 The number of stable arrangements ......................... 190 Band assignment ........................................... 191 SRO IN TREMOLITE-MAGNESIOHORNBLENDE SOLID-SOLUTIONS ........... 192 SRO IN PARVO-MANGANO-EDENITE .................................. 197 SHORT-RANGE ORDER-DISORDER OF (OH) AND F IN AMPHIBOLES ........ 198 One-mode and two-mode behavior ............................ 199 The stereochemistry of local coupling within the amphibole structure ..................................... 200 Local arrangements in (OH,F)-bearing amphibole solid-solutions ......................................... 201 Testing for SRO of (OH) and F in richterite ............... 201 Testing for SRO of (OH) and F in pargasite ................ 203 SHORT-RANGE DISORDER OF Ti4+ AND Si ........................... 204 Band assignment ........................................... 205 Local stereochemistry ..................................... 205 SHORT-RANGE ORDER OF Ti4+ AND O2- .............................. 205 SHORT-RANGE ORDER OF CATIONS AROUND THE A SITE ................ 207 C2/m amphiboles ........................................... 207 The effects of variation in T(Al,Si) and C(M2+, M3+) ........ 210 The effects of variation in O(3)(OH,F) ..................... 211 The relative stability of local arrangements .............. 213 Assignment of local arrangements in structures ............ 213 SUMMARY ....................................................... 216 ACKNOWLEDGMENTS ............................................... 217 REFERENCES .................................................... 217 APPENDIX I: (Mg,Fe2+) ORDER-DISORDER AND BAND INTENSITIES IN THE IR SPECTRUM ........................................... 222 6 Non-Ambient in situ Studies of Amphiboles Mark D. Welch, Fernando Cámara Giancarlo Delia Ventura, Gianluca Iezzi INTRODUCTION .................................................. 223 TRANSITIONAL BEHAVIOR ......................................... 224 The nature of the P2l/m ↔ HT-C2/m transition in amphiboles .............................................. 224 Application of the Landau Theory of phase transitions ..... 226 Spectroscopy of structural phase transitions in amphibole: introductory comments ........................ 231 (Mg,Fe) cummingtonite: high-T studies ..................... 232 (Mg,Fe) cummingtonite: high-P studies of the HT-C2/m → P2l/m transition ........................................ 232 Mn-Mg cummingtonite ....................................... 238 P2l/m ↔ HT-C2/m transition in synthetic amphiboles ........ 239 Overall compositional trends and the P2l/m ↔ HT-C2/m transition .............................................. 243 Comparisons with the P2l/c ↔ C2/c transitions in pyroxenes ............................................... 243 A possible high-pressure P2l/m ↔ "HP-C2/m" transition in amphibole: synthetic ANa B(NaMg) CMg5 TSi8 O22 W(OH)2 and ANa B(LiMg) CMg5 TSi8 O22 W(OH)2 ...................... 246 Other transitional behavior ............................... 247 IN SITU HIGH-TEMPERATURE STUDIES OF CATION ORDER-DISORDER ..... 249 In situ high-T neutron diffraction studies of amphiboles .............................................. 249 Mg-Mn and Fe-Mn ordering in mangano-manganocummingtonite and manganogrunerite .................................... 249 C(Ni-Mg) disorder in K-richterite ......................... 252 AMPHIBOLE COMPRESSIBILITIES ................................... 252 THERMAL EXPANSIVITIES ......................................... 257 IDEAS FOR FUTURE STUDIES AND DIRECTIONS ....................... 257 REFERENCES .................................................... 258 7 The Synthesis and Stability of Some End-Member Amphiboles Bernard W. Evans INTRODUCTION .................................................. 261 TREMOLITE Ca2Mg5Si8O22(OH)2 ................................... 262 FERRO-ACTINOLITE Ca2Fe5Si8O22(OH)2 ............................ 266 ANTHOPHYLLITE Mg2Mg5Si8O22(OH)2 ............................... 269 GRUNERITE Fe2Fe5Si8O22(OH)2 ................................... 271 GLAUCOPHANE Na2(Mg3Al2)Si8O22(OH)2 ............................ 271 RIEBECKITE-ARFVEDSONITE Na2(Fe2+,Fe3+2)Si8O22(OH)2-NaNa2(Fe2+4Fe3+)Si8O22(OH)2 ......... 272 MAGNESIORIEBECKITE-MAGNESIO-ARFVEDSONITE Na2(Mg3Fe3+2)Si8O22(OH)2-NaNa2(Mg4Fe3+)Si8O22(OH)2 ............. 278 RICHTERITE Na(CaNa)Mg5Si8O22(OH)2 .............................. 279 PARGASITE NaCa2(Mg4Al)Si6Al2O22(OH)2 ............................ 280 TSCHERMAKITE Ca2(Mg3Al2)Si6Al2O22(OH)2 ......................... 280 GENERAL CONCLUSIONS ........................................... 281 ACKNOWLEDGMENTS ............................................... 282 REFERENCES .................................................... 282 8 The Significance of the Reaction Path in Synthesizing Single-Phase Amphibole of Denned Composition Walter V. Maresch, Michael Czank INTRODUCTION .................................................. 287 INHERENT PROBLEMS ASSOCIATED WITH THE EXPERIMENTAL METHOD ..... 289 POLYSOMATIC REACTION PATHS .................................... 289 Defect structures as a proxy for the reaction path ........ 289 End-member synthetic tremolite ............................ 295 Amphibole solid solutions radiating from synthetic end-member tremolite .................................... 302 Synthetic amphiboles in the system MgO-FeO-MnO-SiO2-H2O ... 304 Is there a recipe? ........................................ 312 AMPHIBOLE SOLID SOLUTIONS RADIATING FROM SYNTHETIC AMPHIBOLES IN THE SYSTEM MgO-FeO-MnO-SiO2-H2O ............... 313 THE FLUID PHASE AND THE REACTION PATH ......................... 314 Synthesis with dissolved chlorides in the coexisting fluid ................................................... 314 Synthesis with a saturated aqueous fluid .................. 317 CONCLUSIONS ................................................... 319 ACKNOWDLEDGMENTS .............................................. 319 REFERENCES .................................................... 319 9 Amphiboles in the Igneous Environment Robert F. Martin INTRODUCTION .................................................. 323 AMPHIBOLES IN IGNEOUS ROCKS ASSOCIATED WITH EXTENSION IN THE CRUST ....................................................... 324 Pargasite - hawaiitic magma as a pseudo-unary system? ..... 324 The importance of pargasite in the fertilization of the upper mantle ............................................ 325 The importance of pargasite in the generation of alkaline basic magma in the mantle ............................... 327 The oxidation state of iron in mantle-derived amphiboles in nodules and megacrysts ............................... 329 Amphibole minerals in derivatives of alkaline basic magmas .................................................. 330 Amphiboles in juxtaposed SiO2-undersaturated and SiO2-oversaturated derivatives .......................... 335 Amphiboles in SiO2-oversaturated anorogenic suites ........ 335 THE AMPHIBOLE MINERALOGY OF OTHER MANTLE-DERIVED ROCKS ........ 337 Amphiboles in kimberlites and lamproites .................. 337 Amphiboles in carbonatites and associated metasomatic rocks ................................................... 339 The amphibole mineralogy of "anatectic pseudocarbonatites" ..................................... 341 AMPHIBOLES IN IGNEOUS ROCKS ASSOCIATED WITH COMPRESSION IN THE CRUST ................................................... 342 The amphibole mineralogy of arc-related rocks ............. 343 Amphibole-rich clots in calc-alkaline granitic rocks ...... 346 The question of appinites ................................. 348 Amphibole-dominant pegmatites in Alaskan-Uralian-type complexes ............................................... 348 The occurrence of two-amphibole pairs ..................... 349 Metasomatic phenomena ..................................... 351 AMPHIBOLE IN METEORITES ....................................... 352 CONCLUDING STATEMENT .......................................... 353 ACKOWLEDGMENTS ................................................ 353 REFERENCES .................................................... 353 10 Metamorphic Amphiboles: Composition and Coexistence John C. Schumacher INTRODUCTION .................................................. 359 CHEMICAL SUBSTITUTION IN METAMORPHIC AMPHIBOLES ............... 360 The amphibole formula ..................................... 360 Formula basis and estimates of Fe3+ ....................... 361 Amphibole composition space used here ..................... 361 COMPOSITIONS OF METAMORPHIC AMPHIBOLES ........................ 364 Amphibole data ............................................ 364 Edenite, tschermakite and glaucophane component vectors, and XMg and XcAl in calcic, sodic-calcic and sodic amphiboles .............................................. 366 Edenite, tschermakite and glaucophane component vectors, and XMg and XcAl in (Mg, Fe, Mn) amphiboles .............. 370 Variations in Mg/(Mg + Fe2+) .............................. 375 Compositional variations in Mg, Fe2+, Mn2+ and total R2+ ... 375 Compositional variations at the A-site .................... 381 COEXISTING METAMORPHIC AMPHIBOLES ............................. 384 Assemblages with multiple amphiboles ...................... 384 Evaluating equilibrium coexistence ........................ 384 The basic crystal chemistry of equilibrium coexistence .... 387 Cummingtonite-hornblende .................................. 389 Orthoamphibole-hornblende ................................. 393 Orthoamphibole-cummingtonite .............................. 396 Coexisting orthoamphiboles ................................ 396 Coexisting calcic amphiboles .............................. 398 Coexistence involving sodic and sodic-calcic amphiboles ... 400 Coexistence of three or more amphiboles ................... 400 FINAL REMARKS ................................................. 402 ACKNOWLEDGMENTS ............................................... 403 REFERENCES .................................................... 403 SOURCES OF AMPHIBOLE ANALYSES ................................. 406 APPENDIX I .................................................... 413 Recalculating amphibole formulae from electron microprobe analyses ..................................... 413 11 Trace-Element Partitioning Between Amphibole and Silicate Melt Massimo Tiepolo, Roberta Oberti, Alberto Zanetti Riccardo Vannucci, Stephen F. Foley INTRODUCTION .................................................. 417 PARTITION COEFFICIENTS ........................................ 420 FACTORS AFFECTING SOLID/LIQUID PARTITION COEFFICIENTS ......... 421 AMPH/LD FOR THE LIGHT LITHOPHILE ELEMENTS (LLE) ................. 422 Source of data ............................................ 422 Overall values ............................................ 422 Site preference ........................................... 423 Factors affecting Amph/LDLEE ................................ 423 AMPH/LD FOR ALKALINE AND ALKALINE-EARTH LARGE ION LITHOPHILE ELEMENTS (LILE) ............................................. 425 Source of data ............................................ 425 Overall values ............................................ 425 Site preference ........................................... 425 Factors affecting Amph/LDLILE ................................ 425 AMPH/LD FOR RARE EARTH ELEMENTS (REE) AND Y ..................... 428 Source of data ............................................ 428 Overall values ............................................ 428 Site preference ........................................... 428 Factors affecting Amph/LDREE ............................... 432 AMPH/LD FOR HIGH FIELD STRENGTH ELEMENTS (HFSE) ................ 435 Source of data ............................................ 435 Overall values ............................................ 435 Site preference ........................................... 438 Factors affecting Amph/LDHFSE ............................... 439 AMPH/LD FOR ACTINIDES AND Pb ................................... 441 Source of data ............................................ 441 Overall values ............................................ 441 Site preference ........................................... 442 Factors affecting Amph/LDU,Th,Pb ............................. 442 AMPH/LD FOR TRANSITION METALS (Cr, V AND Sc) ................... 443 Source of data ............................................ 443 Overall values ............................................ 444 Site preference ........................................... 444 Factors affecting Amph/LDCr,V,Sc ............................. 444 DIFFERENCES TO THE PARTITIONING BEHAVIOR OBSERVED IN POTASSIC-RICHTERITES ..................................... 445 ON THE CORRECT CHOICE OF AMPH/LD ................................ 448 ACKNOWLEDGMENTS ............................................... 449 REFERENCES .................................................... 449 12 Amphiboles: Environmental and Health Concerns Mickey E. Gunter, Elena Belluso, Annibale Mottana INTRODUCTION .................................................. 453 NOMENCLATURE AND BACKGROUND INFORMATION ....................... 454 Mineralogical ............................................. 454 Medical ................................................... 457 ANALYTICAL METHODS ............................................ 460 Microscopic methods ....................................... 460 DIFFRACTION METHODS ........................................... 464 Chemical determination .................................... 466 MORPHOLOGY MATTERS ............................................ 469 REGULATORY AND LEGAL ISSUES ................................... 472 Regulated mineral species ................................. 473 GEOLOGICAL OCCURRENCE ......................................... 475 Association with rock type ................................ 475 Association with other fibrous minerals ................... 477 Amphiboles in soils and unconsolidated material ........... 478 OCCUPATIONAL VS. NONOCCUPATIONAL EXPOSURE ..................... 479 CURRENT EXAMPLES OF AMPHIBOLE EXPOSURE ........................ 483 Libby, Montana, USA ....................................... 483 El Dorado Hills, California, USA .......................... 486 Biancavilla, Sicily, Italy ................................ 492 AMPHIBOLES IN BIOLOGICAL MATERIALS AND ASSOCIATED BIO-MARKERS ................................................. 494 Amphibole in human lungs .................................. 495 Biomarkers ................................................ 499 Amphiboles in animal lungs ................................ 501 Amphiboles in human urine ................................. 503 Conclusion for humans and animals ......................... 504 STABILITY OF AMPHIBOLES ....................................... 504 Temperature conversions ................................... 505 In the lung ............................................... 506 FUTURE AREAS OF RESEARCH ...................................... 507 SUMMARY ....................................................... 508 ACKNOWLEDGMENTS ............................................... 508 REFERENCES .................................................... 509 13 Amphiboles: Historical Perspective Curzio Cipriani INTRODUCTION .................................................. 517 ANTIQUITY ..................................................... 518 THE EIGHTEENTH CENTURY ........................................ 518 THE NINETEENTH CENTURY ........................................ 521 THE TWENTIETH CENTURY ......................................... 535 PROBLEM OF WATER .............................................. 541 NOMENCLATURE .................................................. 542 CONCLUSIONS ................................................... 544 REFERENCES .................................................... 544