McSween H., Huss G. / Максвин Х., Хьюсс Г. - Cosmochemistry / Космохимия [2010, PDF, ENG]

1 Introduction to cosmochemistry 1
Overview 1
What is cosmochemistry? 1
Geochemistry versus cosmochemistry 3
Beginnings of cosmochemistry (and geochemistry) 6
Philosophical foundations 6
Meteorites and microscopy 6
Spectroscopy and the compositions of stars 9
Solar system element abundances 10
Isotopes and nuclear physics 11
Space exploration and samples from other worlds 14
New sources of extraterrestrial materials 18
Organic matter and extraterrestrial life? 20
The tools and datasets of cosmochemistry 20
Laboratory and spacecraft analyses 21
Cosmochemical theory 24
Relationship of cosmochemistry to other disciplines 25
Questions 26
Suggestions for further reading 26
References 27
2 Nuclides and elements: the building blocks of matter 29
Overview 29
Elementary particles, isotopes, and elements 29
Chart of the nuclides: organizing elements by their nuclear properties 32
Radioactive elements and their modes of decay 35
The periodic table: organizing elements by their chemistry properties 38
Chemical bonding 44
Chemical and physical processes relevant to cosmochemistry 46
Isotope effects from chemical and physical processes 49
Summary 51
Questions 52
Suggestions for further reading 52
References 52
3 Origin of the elements 54
Overview 54
In the beginning 54
The Big Bang model 55
Observational evidence 56
Nucleosynthesis in stars 58
Classification, masses, and lifetimes of stars 61
The life cycles of stars 64
Stellar nucleosynthesis processes 72
Origin of the galaxy and galactic chemical evolution 81
Summary 82
Questions 83
Suggestions for further reading 84
References 84
4 Solar system and cosmic abundances: elements and isotopes 85
Overview 85
Chemistry on a grand scale 85
Historical perspective 85
How are solar system abundances determined? 87
Determining elemental abundances in the Sun 88
Spectroscopic observations of the Sun 88
Collecting and analyzing the solar wind 96
Determining chemical abundances in meteorites 99
Importance of CI chondrites 99
Measuring CI abundances 100
Indirect methods of estimating abundances 101
Solar system abundances of the elements 102
Solar system abundances of the isotopes 104
How did solar system abundances arise? 110
Differences between solar system and cosmic abundances 111
How are solar system abundances used in cosmochemistry? 113
Summary 116
Questions 117
Suggestions for further reading 117
References 118
5 Presolar grains: a record of stellar nucleosynthesis and processes
in interstellar space 120
Overview 120
Grains that predate the solar system 120
A cosmochemical detective story 122
Recognizing presolar grains in meteorites 125
Known types of presolar grains 127
Identification and characterization of presolar grains 128
Locating and identifying presolar grains 128
Characterization of presolar grains 129
Identification of stellar sources 132
Grains from AGB stars 132
Supernova grains 139
Nova grains 139
Other stellar sources 140
Presolar grains as probes of stellar nucleosynthesis 140
Input data for stellar models 141
Internal stellar structure 141
The neutron source(s) for the s-process 142
Constraining supernova models 143
Galactic chemical evolution 144
Presolar grains as tracers of circumstellar and interstellar environments 146
Silicon carbide 146
Graphite grains from AGB stars 146
Graphite grains from supernovae 148
Interstellar grains 149
Presolar grains as probes of the early solar system 149
Summary 152
Questions 153
Suggestions for further reading 153
References 154
6 Meteorites: a record of nebular and planetary processes 157
Overview 157
Primitive versus differentiated 157
Components of chondrites 158
Chondrules 158
Refractory inclusions 163
Metals and sulfide 164
Matrix 164
Chondrite classification 165
Primary characteristics: chemical compositions 166
Secondary characteristics: petrologic types 168
Chondrite taxonomy 170
Other classification parameters: shock and weathering 170
Oxygen isotopes in chondrites 171
Classification of nonchondritic meteorites 173
Primitive achondrites 174
Acapulcoites and lodranites 175
Ureilites 176
Winonaites and IAB silicate inclusions 178
Magmatic achondrites 178
Aubrites 178
Howardites–eucrites–diogenites 179
Angrites 179
Irons and stony irons 180
Classification and composition of iron meteorites 180
Pallasites and mesosiderites 182
Lunar samples 182
Martian meteorites 184
Oxygen isotopes in differentiated meteorites 185
Summary 187
Questions 188
Suggestions for further reading 188
References 189
7 Cosmochemical and geochemical fractionations 192
Overview 192
What are chemical fractionations and why are they important? 192
Condensation as a fractionation process 195
Condensation sequences 196
Applicability of condensation calculations to the early solar system 201
Volatile element depletions 205
Gas–solid interactions 206
Gas–liquid interactions 208
Igneous fractionations 210
Magmatic processes that lead to fractionation 210
Element partitioning 211
Physical fractionations 213
Sorting of chondrite components 213
Fractionations by impacts or pyroclastic activity 215
Element fractionation resulting from oxidation/reduction 217
Element fractionation resulting from planetary differentiation 218
Fractionation of isotopes 220
Mass-dependent fractionation 220
Fractionations produced by ion–molecule reactions 221
Planetary mass-dependent fractionations 222
Mass-independent fractionation 222
Radiogenic isotope fractionation and planetary differentiation 224
Summary 225
Questions 226
Suggestions for further reading 226
References 227
8 Radioisotopes as chronometers 230
Overview 230
Methods of age determination 230
Discussing radiometric ages and time 231
Basic principles of radiometric age dating 231
Long-lived radionuclides 237
The
40
K–40
Ar system 238
The
87
Rb–87
Sr system 242
The
147
Sm–143
Nd system 252
The U–Th–Pb system 258
The
187
Re–187
Os system 270
The
176
Lu–176
Hf system 274
Other long-lived nuclides of potential cosmochemical significance 276
Short-lived radionuclides 278
The
129
I–129
Xe system 282
The
26
Al–26
Mg system 284
The
41
Ca–41
K system 287
The
53
Mn–53
Cr system 288
The
60
Fe–60
Ni system 289
The
107
Pd–107
Ag system 291
The
146
Sm–142
Nd system 293
The
182
Hf–182
W system 294
The
10
Be–10
B system 295
Other short-lived nuclides of potential cosmochemical significance 297
Summary 298
Questions 299
Suggestions for further reading 299
References 300
9 Chronology of the solar system from radioactive isotopes 308
Overview 308
Age of the elements and environment in which the Sun formed 308
Age of the solar system 315
Early solar system chronology 318
Primitive components in chondrites 319
Accretion and history of chondritic parent bodies 324
Accretion and differentiation of achondritic parent bodies 327
Accretion, differentiation, and igneous history of planets and the Moon 330
Age of the Earth 330
Age of the Moon 331
Age of Mars 332
Shock ages and impact histories 336
Shock ages of meteorites 336
Shock ages of lunar rocks 339
The late heavy bombardment 340
Cosmogenic nuclides in meteorites 340
Cosmic-ray exposure ages 340
Terrestrial ages 345
Summary 346
Questions 347
Suggestions for further reading 347
References 348
10 The most volatile elements and compounds: organic matter,
noble gases, and ices 354
Overview 354
Volatility 354
Organic matter: occurrence and complexity 355
Extractable organic matter in chondrites 356
Insoluble macromolecules in chondrites 362
Stable isotopes in organic compounds 364
Are organic compounds interstellar or nebular? 366
Noble gases and how they are analyzed 370
Noble gas components in extraterrestrial samples 371
Nuclear components 371
The solar components 372
Planetary components 373
Planetary atmospheres 375
Condensation and accretion of ices 377
Summary 378
Questions 379
Suggestions for further reading 379
References 380
11 Chemistry of anhydrous planetesimals 382
Overview 382
Dry asteroids and meteorites 382
Asteroids: a geologic context for meteorites 383
Appearance and physical properties 383
Spectroscopy and classification 385
Orbits, distribution, and delivery 389
Chemical compositions of anhydrous asteroids and meteorites 390
Analyses of asteroids by spacecraft remote sensing 390
Chondritic meteorites 392
Differentiated meteorites 396
Thermal evolution of anhydrous asteroids 398
Thermal structure of the asteroid belt 403
Collisions among asteroids 406
Summary 408
Questions 409
Suggestions for further reading 409
References 410
12 Chemistry of comets and other ice-bearing planetesimals 412
Overview 412
Icy bodies in the solar system 412
Orbital and physical characteristics 413
Orbits 413
Appearance and physical properties 414
Chemistry of comets 418
Comet ices 418
Comet dust: spectroscopy and spacecraft analysis 419
Interplanetary dust particles 422
Returned comet samples 426
Ice-bearing asteroids and altered meteorites 432
Spectroscopy of asteroids formed beyond the snowline 432
Aqueous alteration of chondrites 433
Thermal evolution of ice-bearing bodies 436
Chemistry of hydrated carbonaceous chondrites 436
Variations among ice-bearing planetesimals 439
Summary 440
Questions 441
Suggestions for further reading 441
References 442
13 Geochemical exploration of planets: Moon and Mars
as case studies 445
Overview 445
Why the Moon and Mars? 445
Global geologic context for lunar geochemistry 446
Geochemical tools for lunar exploration 448
Instruments on orbiting spacecraft 448
Laboratory analysis of returned lunar samples and lunar
meteorites 450
Measured composition of the lunar crust 451
Sample geochemistry 451
Geochemical mapping by spacecraft 452
Compositions of the lunar mantle and core 456
Geochemical evolution of the Moon 459
Global geologic context for Mars geochemistry 462
Geochemical tools for Mars exploration 464
Instruments on orbiting spacecraft 464
Instruments on landers and rovers 465
Laboratory analyses of Martian meteorites 466
Measured composition of the Martian crust 469
Composition of the crust 470
Water, chemical weathering, and evaporites 472
Compositions of the Martian mantle and core 475
Geochemical evolution of Mars 477
Summary 477
Questions 478
Suggestions for further reading 478
References 479
14 Cosmochemical models for the formation of the solar system 484
Overview 484
Constraints on the nebula 484
From gas and dust to Sun and accretion disk 484
Temperatures in the accretion disk 489
Localized heating: nebular shocks and the X-wind model 492
Accretion and bulk compositions of planets 495
Agglomeration of planetesimals and planets 495
Constraints on planet bulk compositions 495
Models for estimating bulk chemistry 498
Formation of the terrestrial planets 499
Planetesimal building blocks 499
Delivery of volatiles to the terrestrial planets 503
Planetary differentiation 504
Formation of the giant planets 507
Orbital and collisional evolution of the modern solar system 511
Summary 512
Questions 513
Suggestions for further reading 514
References 514
Appendix: Some analytical techniques commonly used
in cosmochemistry 518
Chemical compositions of bulk samples 518
Wet chemical analysis 518
X-ray fluorescence (XRF) 519
Neutron activation analysis 519
Petrology, mineralogy, mineral chemistry, and mineral structure 520
Optical microscopy 520
Electron-beam techniques 520
Other techniques for determining chemical composition
and mineral structure 525
Proton-induced X-ray emission (PIXE) 525
Inductively coupled-plasma atomic-emission spectroscopy
(ICP-AES) 525
X-ray diffraction (XRD) 525
Synchrotron techniques 526
Mass spectrometry 527
Ion sources 527
Mass analyzers 528
Detectors 530
Mass spectrometer systems used in cosmochemistry 531
Raman spectroscopy 534
Flight instruments 535
Gamma-ray and neutron spectrometers 535
Alpha-particle X-ray spectrometer 536
Mössbauer spectrometer 536
Sample preparation 536
Thin-section preparation 536
Sample preparation for EBSD 537
Sample preparation for the TEM 537
Preparing aerogel “keystones” 538
Preparation of samples for TIMS and ICPMS 538
Details of radiometric dating systems using neutron activation 539
40
Ar–39
Ar dating 539
129
I–129
Xe dating 540
Suggestions for further reading 541
Index 543