Preface ........................................................ xi
Acknowledgments .............................................. xiii
1 Basics ....................................................... 1
1.1 Nuclear Size and Constituents ........................... 1
1.2 Fundamental Forces ...................................... 2
1.3 Nuclear Mass ............................................ 3
1.4 Equivalence of Mass and Energy .......................... 3
1.5 Periodic Table .......................................... 4
1.6 Nuclear Composition and Stability ....................... 6
1.7 Nuclear Binding Energy .................................. 8
1.8 Cosmic Abundances ....................................... 9
2 Nuclear Transformations ..................................... 12
2.1 Introduction ........................................... 12
2.2 Spontaneous Nuclear Transformations .................... 12
2.3 Induced Nuclear Transformations ........................ 15
2.4 Induced Nuclear Transformations in the Laboratory and
Nature ................................................. 16
2.5 Role of Natural Radioactivity in Geodynamics and
Geochronology .......................................... 17
2.6 Statistical Aspect of Radioactivity .................... 18
2.7 Binomial Distribution for Radioactive Disintegrations .. 21
2.8 Poisson Distribution ................................... 21
3 Nucleosynthesis ............................................. 23
3.1 Introduction ........................................... 23
3.2 Stellar Nucleosynthesis ................................ 24
4 Isotopics ................................................... 33
4.1 Introduction ........................................... 33
4.2 Isotopic Abundance ..................................... 33
4.3 Isotope Effect in the Nuclear and Atomic Domains ....... 34
4.4 Notation of Isotopic Abundances ........................ 34
4.5 Mixtures of Isotopically Different Components .......... 36
5 Radioactivity and Radiometric Dating ........................ 40
5.1 Introduction ........................................... 40
5.2 Radioactive and Radiogenic Isotope Dating .............. 43
5.3 Long-lived Parent-daughter Couples used in
Radiometric Dating ..................................... 48
5.4 Short-lived Parent-daughter Couples used in
Radiometric Dating ..................................... 53
5.5 Interpretation of t. Radioactive Decay Interval ........ 58
5.6 Isochron Concept, Isotope Equilibration, and Closure
Temperature ............................................ 58
5.7 Termination of a Single Stage Growth in the Past ....... 61
5.8 Recognition of Events Causing Isotopic Equilibration
on Different Scales .................................... 63
5.9 Projection of Present Day Isotopic Composition Back
in Time ................................................ 64
5.10 Reservoir Ages ......................................... 66
5.11 Coupling Two Different, But Chemically Identical
Parent-daughter Systems ................................ 67
5.12 Concordia and Discordia ................................ 71
5.13 Coupling Two Chemically Different Decay Systems ........ 74
5.14 Chemical and Half-life Diversity of Parent-daughter
Pairs .................................................. 76
5.15 Radiometric Dating by Indirect Radiogenic Effects ...... 77
5.16 Conclusion ............................................. 79
6 Mass Spectrometry and Isotope Geochemistry .................. 80
6.1 Introduction ........................................... 80
6.2 Principles of Mass Spectrometry ........................ 81
6.3 Ion Detectors .......................................... 82
6.4 Sequential vs Simultaneous Detection of Ion Beams ...... 83
6.5 Improved Mass Spectrometers ............................ 85
6.6 Types of Ion Sources Used in Isotope Geochemistry ...... 86
6.7 Typical Commercial Mass Spectrometers Using Different
Ion Sources ............................................ 88
6.8 Mass Fractionation in Mass Spectrometers ............... 91
6.9 Absolute Abundance of an Isotope ....................... 92
6.10 Sample Size Requirements ............................... 93
6.11 Mass Spectrometry vs Decay Counting .................... 93
6.12 Accelerator Mass Spectrometer .......................... 94
7 Error Analysis .............................................. 96
7.1 Introduction ........................................... 96
7.2 Systematic and Random Errors ........................... 97
7.3 Measurement of Random Data ............................. 97
7.4 Population Mean and Sample Mean ........................ 98
7.5 Propagation of Measurement Uncertainties .............. 101
7.6 Standard Deviation of the Mean of n Measurements ...... 102
7.7 Joint Variation of Two or More Random Variables ....... 103
7.8 Regression Analysis ................................... 105
7.9 York's Solution ....................................... 106
7.10 Measure of Goodness-of-fit ............................ 109
8 Meteorites; Link between Cosmo- and Geochemistry ........... 100
8.1 Introduction .......................................... 100
8.2 Nucleocosmochronology ................................. 111
8.3 Extinct Nuclides and Formation Interval ............... 112
8.4 Meteorites ............................................ 114
8.5 Nebular condensation .................................. 117
8.6 Planetary Accretion ................................... 118
8.7 Isotope Abundances in the Solar Nebula ................ 119
9 Clironology of Meteorite History ........................... 121
9.1 Introduction .......................................... 121
9.2 Stage 1: Formation Intervals from Extinct Isotopes .... 124
9.3 Stages 2 through 4: Formation Ages of Meteorites ...... 127
9.4 Rb-Sr, Sm-Nd and U-Pb Ages of Meteorites .............. 129
9.5 Very High Precision Model Ages ........................ 131
9.6 Meteorite Ages Much Younger than 4.5 Ga ............... 134
9.7 Stage 5: Gas Retention Ages and Post-Formational
Cooling and Heating Histories ......................... 134
9.8 Stage 6: Duration of Meteorites as Small Independent
Objects in Space ...................................... 137
9.9 Stage 7: Terrestrial Residence Time of Meteorite
Finds ................................................. 139
10 Chemical Evolution of the Earth ............................ 140
10.1 Composition of Terrestrial Planets and Chondritic
Meteorites ........................................... 140
10.2 Energetic Processes During the Final Stages of Earth
Accretion ............................................ 141
10.3 Element Segregation: Some Geochemical Rules .......... 142
10.4 Segregation of Major and Trace Elements During
Melting or Igneous Processes ......................... 143
10.5 Graphical Representation of Inter-Element
Variations in Compatibility .......................... 145
10.6 Melting and Crystallization Models ................... 146
10.7 Combined Partial Melting and Recrystallization ....... 150
10.8 Observational Constraints on the Structure and
Composition of the Modem Mantle ...................... 151
10.9 Earth as a Large Geochemical System .................. 155
10.10 Elemental Chemistry of Mid-Ocean-Ridge Basalts,
Ocean-Island Basalts and Continental Crust ........... 157
11 Chronology of Earth History ................................ 161
11.1 Introduction ......................................... 161
11.2 Early Siderophile-Lithophile Segregation and Timing
of Core Formation .................................... 163
11.3 Eariy Lithophile-Atmophile Separation and Timing of
the Primitive Atmosphere ............................. 165
11.4 Lithophile-Lithophile Separation and Timing of the
Early Crust .......................................... 168
11.5 142Nd Evolution in the Earth's Mantle ................ 171
11.6 143Nd Evolution in the Earth's Mantle ................ 172
11.7 87Sr Evolution in the Earth's Mantle ................. 175
11.8 Coupling Neodymium and Strontium Data ................ 176
11.9 206Pb, 207Pb Evolution in the Earth's Mantle .......... 180
11.10 Evolution of 176Hf in the Earth's Mantle ............. 182
11.11 Evolution of 187Os in the Earth's Mantle ............. 182
11.12 Evolution of Strontium and Neodymium Isotope Ratios
in Seawater .......................................... 183
11.13 Magma Sources in the Mantle .......................... 185
11.14 Evolution of Radioactive Daughter Isotopes ........... 188
11.15 Giant Impact Hypothesis .............................. 191
References .................................................... 192
Index ......................................................... 203
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