Reviews in mineralogy and geochemistry. Vol.68: Oxygen in the solar system / ed. by Rosso J.J. - Washington, DC: Mineralogical Society of America, 2008. - 598 p. - ISSN 1529-6466  Место хранения:   09 | Институт геохимии им. А.П.Виноградова СО РАН | Иркутск | Библиотека

Оглавление / Contents

I. INTRODUCTION .............................................. 1 2. OXYGEN ISOTOPES IN THE EARLY SOLAR SYSTEM A HISTORICAL PERSPECTIVE Robert N.Clayton ABSTRACT .................................................... 5 BEFORE ALLENDE .............................................. 5 AFTER ALLENDE ............................................... 6 FUNCAIs ..................................................... 8 OXYGEN ISOTOPES IN PRESOLAR GRAINS .......................... 9 CHEMICAL ISOTOPE EFFECTS .................................... 9 PHOTOCHEMICAL EFFECTS ...................................... 10 INTERNAL ASTEROIDAL PROCESSES .............................. 10 NITROGEN ................................................... 11 CONCLUSIONS ................................................ 12 ACKNOWLEDGMENT ............................................. 12 REFERENCES ................................................. 12 3. ABUNDANCE, NOTATION, AND FRACTIONATION OF LIGHT STABLE ISOTOPES Robert E.Criss, James Farquhar ABSTRACT ................................................... 15 INTRODUCTION ............................................... 15 ISOTOPIC ABUNDANCES AND ATOMIC WEIGHTS ..................... 16 NOTATION ................................................... 18 Isotope ratios ......................................... 18 δ-values ............................................... 19 Isotopic fractionation factor .......................... 19 Big delta and related approximations ................... 19 Capital delta .......................................... 20 Capital delta prime and delta prime .................... 20 Material balance ....................................... 21 COMMONLY-USED DIAGRAMS ..................................... 21 δ-δ plot ............................................... 21 Big Д and Cap Д plots .................................. 21 Three-isotope plot ..................................... 22 ISOTOPIC FRACTIONATION PROCESSES ........................... 24 Mass-dependent fractionation ........................... 24 Kinetic processes ...................................... 26 Non-mass-dependent fractionations ...................... 27 CONCLUSIONS ................................................ 28 REFERENCES ................................................. 29 4. NUCLEOSYNTHESIS AND CHEMICAL EVOLUTION OF OXYGEN Bradley S.Meyer, Larry R.Nittler, Ann N.Nguyen, Scott Messenger ABSTRACT ................................................... 31 INTRODUCTION ............................................... 31 NUCLEOSYNTHESIS OF THE ISOTOPES OF OXYGEN .................. 32 Production of oxygen in mainline stellar burning stages ................................................. 32 Analysis of the oxygen yields from massive stars ....... 36 Low-mass stars ......................................... 38 Novae and Type Ia supernovae ........................... 41 CHEMICAL EVOLUTION OF THE ISOTOPES OF OXYGEN ............... 41 OXYGEN IN PRESOLAR GRAINS .................................. 45 Oxygen in carbonaceous grains .......................... 46 Presolar oxide and silicate grains ..................... 47 CONCLUDING REMARKS ......................................... 50 ACKNOWLEDGMENTS ............................................ 51 REFERENCES ................................................. 51 5. OXYGEN IN THE INTERSTELLAR MEDIUM Adam G.Jensen, F.Markwick-Kemper, Theodore P.Snow ABSTRACT ................................................... 55 INTRODUCTION ............................................... 55 Phases in the interstellar medium ...................... 56 Forms of oxygen in the interstellar medium ............. 56 OXYGEN IN THE GAS PHASS .................................... 56 Measurements of gas-phase oxygen ....................... 56 Isotope measurements from gas-phase oxygen and carbon monoxide ........................................ 60 Inferring gas-phase depletions of oxygen ............... 61 OXYGEN IN INTERSTELLAR DUST ................................ 63 Solar System silicates ................................. 63 Silicates in circumstellar environments of young stars .................................................. 63 Dust properties in the interstellar medium ............. 64 Dust production by evolved stars ....................... 65 CONSISTENCY BETWEEN GAS AND SOLID PHASES ................... 66 Abundance and depletion constraints .................... 66 Transitions between the solid and gas phase in the interstellar medium .................................... 67 SUMMARY .................................................... 68 REFERENCES ................................................. 68 6. OXYGEN IN THE SUN Andrew M.Davis, К.Hashizume, Marc Chaussidon, Trevor R.Ireland, Carlos Allende Prieto, David L.Lambert ABSTRACT ................................................... 73 INTRODUCTION ............................................... 74 THE SOLAR PHOTOSPHERIC ABUNDANCE OF OXYGEN ................. 74 OXYGEN ISOTOPIC COMPOSITION OF THE SUN ..................... 77 Predictions of the isotopic composition of the Sun ..... 77 Spectroscopic constraints on the oxygen isotopic composition of the Sun ................................. 78 Identification of the solar isotopic composition trapped in lunar samples ............................... 79 Oxygen isotopic composition of the solar wind: direct measurements .................................... 87 Summary of solar oxygen isotopic composition ........... 88 ACKNOWLEDGMENTS ............................................ 89 REFERENCES ................................................. 89 7. REDOX CONDITIONS IN THE SOLAR NEBULA: OBSERVATIONAL, EXPERIMENTAL, AND THEORETICAL CONSTRAINTS Lawrence Grossman, John R.Beckett, Alexei V.Fedkin, Steven B.Simon, Fred J.Ciesla ABSTRACT ................................................... 93 INTRODUCTION ............................................... 94 OXYGEN FUGACITY DURING CRYSTALLIZATION OF REFRACTORY INCLUSION MELTS ................................. 94 Experimental technique ................................. 94 Results ................................................ 96 Thermochemistry ........................................ 99 Selection of fassaite-melilite pairs .................. 103 Oxygen barometry ...................................... 105 THE OXIDATION STATE OF IRON IN ORDINARY CHONDRITES ........ 109 The problem ........................................... 109 Radial transport processes ............................ 111 Vertical transport processes .......................... 112 Relationship between ƒ01 of cosmic gases and abundances of C, O and H .................... 114 Condensation of fayalitic olivine ..................... 115 Change of FeO/(FeO + MgO) during chondrule melting .... 124 REDOX CONDITIONS INFERRED FROM OTHER IRON-BEARING NEBULAR MATERIALS ......................................... 126 Amoeboid olivine aggregates ........................... 126 Metal grains in CH chondrites ......................... 127 FORMATION CONDITIONS OF ENSTATITE CHONDRITES .............. 127 Mineralogy of EH3 enstatite chondrites ................ 127 Condensation at high C/O ratio ........................ 127 Bulk chemical compositions of EH enstatite chondrites ............................................ 130 Condensation of EH enstatite chondrites ............... 130 Formation conditions of EH3 enstatite chondrites ...... 134 CONCLUSIONS ............................................... 135 ACKNOWLEDGMENTS ........................................... 136 REFERENCES ................................................ 136 8. OXYGEN ISOTOPES OF CHONDRITIC COMPONENTS Hisayoshi Yurimoto, Alexander N.Krot, Byeon-Gak Choi, Jerome Alion, Takuya Kunihiro, Adrian J.Brearley ABSTRACT .................................................. 141 INTRODUCTION .............................................. 142 CHONDRITES AND THEIR COMPONENTS ........................... 144 OXYGEN ISOTOPIC COMPOSITIONS OF SECONDARY PHASES .......... 145 OXYGEN ISOTOPIC COMPOSITIONS OF REFRACTORY INCLUSIONS ..... 149 Alteration and secondary minerals of fine grained CAIs (FGIs) ........................................... 149 ORIGINAL OXYGEN ISOTOPIC DISTRIBUTION OF FGIs ............. 151 FGIs in primitive O chondrites ........................ 151 FGIs in primitive E chondrites ........................ 151 FGIs in CO 3.0 chondrites ............................. 151 FGIs in CR chondrites ................................. 152 FGIs in CM chondrites ................................. 154 FGIs in CV chondrites ................................. 154 FGIs in CH chondrites ................................. 155 FGIs in CB chondrites ................................. 155 Chondrule-bearing FGI ................................. 155 Summary of oxygen isotopic characteristics of FGIs .... 156 Alteration and secondary minerals of amoeboid olivine aggregates (AOAs) ..................................... 156 ORIGINAL OXYGEN ISOTOPIC DISTRIBUTION OF AOAs ............. 158 AOAs in CV chondrites ................................. 158 AOAs in CO, CR, Acfer 094 and CM chondrites ........... 159 Summary of oxygen isotopic characteristics of AOAs .... 161 OXYGEN ISOTOPIC DISTRIBUTION OF COARSE-GRAINED CAIs (CGIs) .................................................... 161 7R-19-1, a compact Type A CGI ......................... 163 E49, a compact Type A CGI ............................. 163 SS-02, a Type B2 CGI .................................. 165 TTVl-01, a TypeB2CGI .................................. 166 1623-2, a compact Type A CGI .......................... 166 V2-01, a fluffy Type A CGI ............................ 167 Chondrule-bearing CGIs ................................ 168 Summary of oxygen isotopic characteristics of CGIs .... 169 OXYGEN ISOTOPIC COMPOSITIONS OF CHONDRULES ................ 169 Chondrules in CH chondrites ........................... 170 Chondrules in CR chondrites ........................... 170 Chondrules in CB chondrites ........................... 170 Chondrules in CO and Acfer 094 chondrites ............. 171 Chondrules in CV chondrites ........................... 172 Chondrules in E chondrites ............................ 172 Chondrules in ordinary chondrites ..................... 172 Refractory inclusion-bearing chondrules ............... 172 Summary of oxygen isotopic characteristics of chondrules ............................................ 174 OXYGEN ISOTOPIC COMPOSITIONS OF MATRIX .................... 175 Existence of submicron silicate grains with extreme non-solar oxygen isotopic compositions ................ 176 Oxygen isotopic heterogeneity of matrix ............... 177 Summary of oxygen isotopic characteristics of matrix ................................................ 179 IMPLICATIONS FOR ASTROPHYSICAL SETTING OF CHONDRITIC COMPONENT FORMATION ....................................... 179 ACKNOWLEDGMENTS ........................................... 181 REFERENCES ................................................ 182 9. MASS-INDEPENDENT OXYGEN ISOTOPE VARIATION IN THE SOLAR NEBULA Edward D.Young, Kyoshi Kuramoto, Rudolph A.Marcus, Hisayoshi Yurimoto, Stein B.Jacobsen ABSTRACT .................................................. 187 INTRODUCTION .............................................. 188 GALACTIC OXYGEN ISOTOPE EVOLUTION-A NON-CHEMICAL PATH TO MASS INDEPENDENCE ................................. 189 Testing the hypothesis - the oxygen isotopic composition of the Sun ............................................ 191 CHEMICAL MASS-INDEPENDENT OXYGEN ISOTOPE FRACTIONATION .... 192 The MIF in ozone formation ............................ 193 Conditions for a chemical MIF in the formation of CAIs .................................................. 195 A possible chemical mechanism for MIF in CAIs ......... 195 Consequences of chemical mechanism for MIF in the early water ........................................... 196 Testing the hypothesis: experiment to test gas phase MIF at high temperature ......................... 197 PHOTOCHEMICAL MASS-INDEPENDENT OXYGEN ISOTOPE FRACTIONATION: CO SELF-SHIELDING .......................... 198 CO photodissociation and self-shielding ............... 198 Astronomical observations of oxygen isotope fractionation by CO self-shielding .................... 200 The pivotal role of H20 ............................... 201 CO self-shielding at the inner annulus of the solar circumstellar disk .................................... 203 CO self-shielding at the surfaces of the solar circumstellar disk .................................... 204 CO self-shielding in molecular clouds and inheritance in the Solar System ................................... 210 Testing the hypotheses: predictions of the CO self-shielding models .............................. 212 SUMMARY ................................................... 213 REFERENCES ................................................ 214 10.OXYGEN AND OTHER VOLATILES IN THE GIANT PLANETS AND THEIR SATELLITES Michael H.Wong, Jonathan I.Lunine, Sushil K.Atreya, Torrence Johnson, Paul R.Mahaffy, Tobias C.Owen, Therese Encrenaz ABSTRACT .................................................. 219 INTRODUCTION .............................................. 220 Oxygen-based insights from the outer planets and their moons ........................................... 220 The protosolar abundances ............................. 221 MEASURING OXYGEN IN JUPITER'S ATMOSPHERE .................. 222 Structure of the cloud layers ......................... 222 Galileo Probe Mass Spectrometer water mixing ratio measurements .......................................... 223 The probe entry site: A 5-μm hot spot ................. 225 Spectroscopic measurements of Jovian water ............ 226 Lightning on Jupiter .................................. 227 Oxygen isotopes in Jupiter ............................ 228 Summary of Jovian oxygen .............................. 228 OUTER PLANET VOLATILE GASES ............................... 229 Oxygen and other heavy element enrichments in Jupiter ............................................... 229 Volatile enrichments in the other outer planets ....... 231 OXYGEN IN OUTER PLANET SATELLITES ......................... 232 Jupiter's satellites .................................. 234 Saturn's satellites ................................... 234 Outer Solar System satellites and Kuiper Belt Objects ............................................... 235 FORMATION OF THE OUTER PLANETS ............................ 236 Volatile enrichment by icy planetesimals .............. 237 Volatile enrichment by carbonaceous planetesimals ..... 238 Volatile enrichment by disk evolution ................. 239 CONCLUSIONS ............................................... 240 ACKNOWLEDGMENTS ........................................... 241 REFERENCES ................................................ 241 11.OXYGEN IN COMETS AND INTERPLANETARY DUST PARTICLES Scott A.Sandford, Scott Messenger, Michael DiSanti, Lindsay Keller, Kathrin Altwegg ABSTRACT .................................................. 247 INTRODUCTION .............................................. 247 THE CHEMICAL FORM OF OXYGEN IN THE INTERSTELLAR MEDIUM, "COMETARY" INTERPLANETARY DUST PARTICLES, AND COMETS ...... 249 Oxygen carried by carbonaceous materials in the interstellar medium, meteorites, cosmic dust, and cometary samples ..................... 249 Direct detection of oxygen-bearing volatiles in comets ................................................ 253 The oxygen-bearing minerals in "cometary" IDPs and samples from comet 81P/Wild2 .......................... 258 OXYGEN ISOTOPES IN THE INTERSTELLAR MEDIUM, COMETS, COMETARY SAMPLES, AND "COMETARY" IDPS ..................... 260 Oxygen isotopes in interstellar materials ............. 261 In situ measurement of the oxygen isotopes in the volatile material of comet Halley ..................... 261 Oxygen isotopic compositions of meteorites, "cometary" IDPs and samples from comet 81P/Vild .................. 262 FUTURE IN SITU MEASUREMENTS OF ISOTOPIC RATIOS IN COMETS .................................................... 264 CONCLUSIONS ............................................... 265 ACKNOWLEDGMENTS ........................................... 265 REFERENCES ................................................ 265 12.OXYGEN AND ASTEROIDS Thomas H.Burbine, Andrew S.Rivkin, Sarah K.Noble, Thais Mothé-Diniz, William F.Bottke, Timothy J.McCoy, M.Darby Dyar, Cristina A.Thomas ABSTRACT .................................................. 273 INTRODUCTION .............................................. 273 DYNAMICAL STRUCTURE OF THE ASTEROID BELT .................. 275 ASTRONOMICAL TECHNIQUES ................................... 276 Brightness ............................................ 276 Reflectance spectroscopy .............................. 276 Spectral data ......................................... 278 Corrections ........................................... 279 Interaction of photons with a surface ................. 281 ABSORPTION BANDS .......................................... 281 Electronic absorption features ........................ 281 Vibrational absorption features ....................... 288 SPACE WEATHERING .......................................... 291 Effect of space weathering on reflectance spectra ..... 291 Space weathering environment of asteroids ............. 293 Experimental studies .................................. 293 Evidence of space weathering on asteroids ............. 294 Implications for visible/near-IR remote sensing ....... 294 ORDINARY CHONDRITES, LODRANITES/ACAPULCOITES, AND UREILITES ................................................. 295 DETERMINING MINERAL CHEMISTRIES ........................... 296 Determining the ratio of olivine to pyroxene .......... 296 Modified Gaussian Modeling ............................ 297 ASTEROID TAXONOMY ......................................... 297 A-types ............................................... 301 C-complex ............................................. 304 D- and P-types ........................................ 306 E- and Xe-types ....................................... 307 K- and L-types ........................................ 308 M-types ............................................... 308 O-types ............................................... 310 Q-types ............................................... 310 R-types ............................................... 310 S-complex ............................................. 310 T-types ............................................... 312 V-types ............................................... 312 HELIOCENTRIC DISTRIBUTIONS OF TAXONOMIC CLASSES IN THE MAIN BELT .......................................... 314 MSTRIBUTION OF HYDRATED ASTEROIDS IN THE MAIN BELT ........ 321 NEAR-EARTH ASTEROIDS ...................................... 323 PACECRAFT MISSIONS ........................................ 324 COLLISIONAL AND DYNAMICAL EVOLUTION OF ASTEROIDS .......... 326 DELIVERY OF METEOROIDS TO EARTH ........................... 327 THE EFFECTS OF PLANETARY EMBRYOS AND RADIAL MIXING IN THE MAIN BELT .......................................... 329 COULD IRON METEORITES HAVE COME FROM THE TERRESTRIAL PLANET REGION? ............................................ 330 SUMMARY ................................................... 331 ACKNOWLEDGMENTS ........................................... 331 REFERENCES ................................................ 331 13.OXYGEN ISOTOPES IN ASTEROIDAL MATERIALS Ian A.Franchi ABSTRACT .................................................. 345 INTRODUCTION .............................................. 346 ORDINARY CHONDRITES ....................................... 349 Introduction .......................................... 349 Ordinary chondrites - whole-rock ...................... 349 Ordinary chondrites - components ...................... 351 R CHONDRITES .............................................. 356 ENSTATITE METEORITES ...................................... 358 Introduction .......................................... 358 EH and EL chondrites ...................................... 358 Aubrites .............................................. 360 CARBONACEOUS CHONDRITES ................................... 361 Introduction .......................................... 361 CV chondrites ......................................... 361 CK chondrites ......................................... 365 CO chondrites ......................................... 366 CM chondrites ......................................... 368 CI chondrites ......................................... 371 CR chondrites ......................................... 372 CH chondrites ......................................... 373 CB chondrites ......................................... 374 PRIMITIVE ACHONDRITES ..................................... 375 Introduction .......................................... 375 Acapulcoites and lodranites ........................... 376 Brachinites ........................................... 377 Winonaites ............................................ 377 Ureilites ............................................. 378 BASALTIC ACHONDRITES ...................................... 379 Introduction .......................................... 379 Howardites, eucrites and diogenites ................... 380 Angrites .............................................. 381 Basaltic inclusions ................................... 382 IRONS AND STONY-IRONS ..................................... 382 Introduction .......................................... 382 IAB Complex ........................................... 383 IIAB .................................................. 384 IIE ................................................... 384 IIIAB ................................................. 385 IVA ................................................... 386 Mesosiderites ......................................... 387 Pallasites ............................................ 387 Ungrouped irons ....................................... 388 CONCLUSIONS ............................................... 389 REFERENCES ................................................ 390 14.OXYGEN ISOTOPIC COMPOSITION AND CHEMICAL CORRELATIONS IN METEORITES AND THE TERRESTRIAL PLANETS David W.Mittlefehldt, Robert N.Clayton, Michael J.Drake, Kevin Righter ABSTRACT .................................................. 399 INTRODUCTION .............................................. 400 BACKGROUND ................................................ 400 Nebular element fractionations ........................ 400 Oxygen isotope anomalies .............................. 403 Mechanisms of non-mass-dependent isotope fractionation ......................................... 405 CHONDRITIC METEORITES ..................................... 407 Micro- and meso-scale correlations .................... 407 Correlations among chondrite groups ................... 408 UREILITES ................................................. 417 TERRESTRIAL PLANETS ....................................... 419 SUMMARY ................................................... 422 ACKNOWLEDGMENTS ........................................... 423 REFERENCES ................................................ 423 15.RECORD OF LOW-TEMPERATURE ALTERATION IN ASTEROIDS Michael E.Zolensky, Alexander N.Krot, Gretchen Benedix ABSTRACT .................................................. 429 INTRODUCTION .............................................. 429 C,P AND D ASTEROIDS - CARBONACEOUS CHONDRITES ............. 430 Aqueous activity on the CI parent asteroid(s) and its oxygen isotope record ......................... 430 Aqueous activity on the CM parent asteroid(s) and its oxygen isotope record ......................... 434 Oxygen isotopic compositions of secondary minerals in the ungrouped carbonaceous chondrite Tagish Lake ... 437 Aqueous alteration of CR chondrites and their oxygen isotope record ........................................ 438 Hydrous and anhydrous alteration of CV chondrites and their oxygen isotope records ...................... 439 Low-temperature aqueous alteration of CO chondrites ... 448 Veritas asteroids - hydrous chondritic interplanetary dust particles ......................... 448 S ASTEROIDS - ORDINARY AND R CHONDRITES ................... 451 Aqueous alteration of ordinary chondrites and its oxygen isotope record ............................. 451 Aqueous alteration of R-chondrites and its oxygen isotope record ........................................ 452 M AND E ASTEROIDS - INCLUDING ENSTATITE CHONDRITES ........ 452 OXYGEN ISOTOPIC COMPOSITION OF ASTEROIDAL WATER AND EVOLUTION OF OXYGEN ISOTOPIC COMPOSITION OF THE INNER PROTOPLANETARY DISK ....................................... 454 SUMMARY AND FUTURE WORK ................................... 455 ACKNOWLEDGMENTS ........................................... 456 REFERENCES ................................................ 456 16.THE OXYGEN CYCLE OF THE TERRESTRIAL PLANETS: INSIGHTS INTO THE PROCESSING AND HISTORY OF OXYGEN IN SURFACE ENVIRONMENTS James Farquhar, David T.Johnston ABSTRACT .................................................. 463 INTRODUCTION .............................................. 463 ISOTOPIC VARIATIONS AMONG TERRESTRIAL MATERIALS ........... 464 Historical account of oxygen isotopic variations of terrestrial reservoirs ................................ 465 Molecular oxygen ...................................... 471 Ozone ................................................. 471 Other oxygen-bearing atmospheric species with nonzero Δ17O .................................................... 473 Multiply substituted molecular species ................ 473 EVOLUTION OF OXYGEN IN EARTH'S SURFACE ENVIRONMENTS ....... 474 Planetary processing of oxygen ........................ 475 OBSERVATIONS RELEVANT TO THE EVOLUTION OF OXYGEN IN THE ATMOSPHERE AND OCEANS ..................................... 476 Hypotheses about the levels of oxygen in Earth's early environments .................................... 476 The transition from a low-oxygen atmosphere to a high oxygen atmosphere ..................................... 480 Into the Paleoproterozoic and Mesoproterozoic ......... 481 Oxygen and Proterozoic carbon cycle ................... 482 Oxygen concentration variations since the end of the Proterozoic ....................................... 483 Conceptual model for oxygenation of Earth surface environments .................................. 484 NEW FRONTIERS ............................................. 485 CONCLUDING STATEMENTS ..................................... 486 ACKNOWLEDGMENTS ........................................... 487 REFERENCES ................................................ 487 17.REDOX CONDITIONS ON SMALL BODIES, THE MOON AND MARS Meenakshi Wadhwa ABSTRACT .................................................. 493 INTRODUCTION .............................................. 493 SMALL BODIES .............................................. 494 Brachinites and other primitive achondrites ............... 494 Ureilites ............................................. 495 Aubrites .............................................. 496 Angrites .............................................. 496 Eucrites .............................................. 496 THE MOON .................................................. 497 MARS ...................................................... 499 OTHER TERRESTRIAL PLANETS ................................. 503 SUMMARY AND CONCLUSIONS ................................... 505 ACKNOWLEDGMENTS ........................................... 506 REFERENCES ................................................ 506 18.TERRESTRIAL OXYGEN ISOTOPE VARIATIONS AND THEIR IMPLICATIONS FOR PLANETARY LITHOSPHERES Robert E.Criss ABSTRACT .................................................. 511 INTRODUCTION .............................................. 511 OXYGEN ISOTOPE GEOCHEMISTRY OF TERRESTRIAL ROCKS .......... 512 Earth's primordial δ18 value .......................... 512 Oxygen isotope variations of terrestrial rocks ........ 513 ISOTOPIC FRACTIONATION PROCESSES .......................... 514 Isotopic fractionation factors ........................ 514 Fractional crystallization and AFC .................... 515 Real magmas ........................................... 516 Subsolidus fractionation processes .................... 517 OXYGEN ISOTOPE ZONATION AND HETEROGENEITY IN PLANETARY LITHOSPHERES .............................................. 519 Processes producing 18O zonation ...................... 519 Processes producing 18O heterogeneity ................. 521 Bulk 18O composition of the continents ................ 523 Isotopic changes over geologic time ................... 524 CONCLUSIONS ............................................... 525 REFERENCES ................................................ 525 19.BASALTS AS PROBES OF PLANETARY INTERIOR REDOX STATE Christopher D.K.Herd ABSTRACT .................................................. 527 INTRODUCTION .............................................. 527 THE OXIDATION STATE OF THE EARTH'S MANTLE ................. 528 The lower mantle ...................................... 530 The upper mantle ...................................... 531 OXYBAROMETERS APPLICABLE TO BASALTIC ROCKS ................ 533 Oxygen fugacity from mineral equilibria ............... 535 Multivalent trace elements ............................ 541 Oxygen fugacity from multivalent trace elements ....... 541 THE BASALT-MANTLE SOURCE REDOX RELATIONSHIP ............... 546 Is basalt oxygen fugacity reflective of the redox state of its mantle source? ........................... 546 Implications for understanding the redox states of planetary interiors ................................... 548 ACKNOWLEDGMENTS ........................................... 549 REFERENCES ................................................ 549 20.RHEOLOGICAL CONSEQUENCES OF REDOX STATE Stephen Mackwell ABSTRACT .................................................. 555 INTRODUCTION .............................................. 555 DEFORMATION OF OLIVINE .................................... 556 Olivine single crystal studies ........................ 556 Olivine aggregate studies ............................. 558 How does oxygen fugacity affect creep of olivine? ......... 562 DEFORMATION OF OTHER SILICATES ............................ 564 How does oxygen fugacity affect creep of other silicates? ........................................... 566 SUMMARY ................................................... 567 REFERENCES ................................................ 568 21.APPENDIX: METEORITES - A BRIEF TUTORIAL David W.Mittlefehldt ABSTRACT .................................................. 571 INTRODUCTION .............................................. 571 CHONDRITES ................................................ 572 Carbonaceous chondrites ............................... 574 Ordinary chondrites ................................... 575 Enstatite chondrites .................................. 576 Rumuruti-like and Kakangari-like chondrites ........... 576 ACHONDRITES ............................................... 576 Acapulcoite-lodranite clan ............................ 577 Winonaites and silicate inclusions from IAB (and possibly IIICD) irons ............................ 579 Angrites .............................................. 579 Aubrites .............................................. 579 Brachinites ........................................... 580 Howardite-eucrite-diogenite clan ...................... 580 Ureilites ............................................. 581 IRONS ..................................................... 581 Magmatic iron meteorite groups ........................ 583 Non-magmatic iron meteorite groups .................... 585 STONY IRONS ............................................... 585 Main-group and Eagle Station grouplet pallasites ...... 585 Mesosiderites ......................................... 586 ACKNOWLEDGMENTS ........................................... 587 REFERENCES ................................................ 587 SUBJECT INDEX .............................................. 591 METEORITE INDEX ............................................ 597