Geochronology and Thermochronology

This book is a welcome introduction and reference for users and innovators in geochronology. It provides modern perspectives on the current state-of-the art in most of the principal areas of geochronology and thermochronology, while recognizing that they are changing at a fast pace. It emphasizes fundamentals and systematics, historical perspective, analytical methods, data interpretation, and some applications chosen from the literature. This book complements existing coverage by expanding on those parts of isotope geochemistry that are concerned with dates and rates and insights into Earth and planetary science that come from temporal perspectives.

Geochronology and Thermochronology offers chapters covering: Foundations of Radioisotopic Dating; Analytical Methods; Interpretational Approaches: Making Sense of Data; Diffusion and Thermochronologic Interpretations; Rb-Sr, Sm-Nd, Lu-Hf; Re-Os and Pt-Os; U-Th-Pb Geochronology and Thermochronology; The K-Ar and ¯40Ar/¯39Ar Systems; Radiation-damage Methods of Geo- and Thermochronology; The (U-Th)/He System; Uranium-series Geochronology; Cosmogenic Nuclides; and Extinct Radionuclide Chronology.

• Offers a foundation for understanding each of the methods and for illuminating directions that will be important in the near future

• Presents the fundamentals, perspectives, and opportunities in modern geochronology in a way that inspires further innovation, creative technique development, and applications

• Provides references to rapidly evolving topics that will enable readers to pursue future developments

Geochronology and Thermochronology is designed for graduate and upper-level undergraduate students with a solid background in mathematics, geochemistry, and geology.

"Geochronology and Thermochronology is an excellent textbook that delivers on the difficult balance between having an appropriate level of detail to be useful for an upper undergraduate to graduate-level class or research reference text without being too esoteric for a more general audience, with content and descriptions that are understandable and enlightening to the non-specialist. I would recommend this textbook for anyone interested in the history, principles, and mechanics of geochronology and thermochronology." --American Mineralogist, 2021

Read an interview with the editors to find out more:
https://eos.org/editors-vox/the-science-of-dates-and-rates

Auteur

Peter W. Reiners, University of Arizona, USA Richard W. Carlson, Carnegie Institution for Science, USA Paul R. Renne, Berkeley Geochronology Center and University of California, USA Kari M. Cooper, University of California, USA Darryl E. Granger, Purdue University, USA Noah M. McLean, University of Kansas, USA Blair Schoene, Princeton University, USA

Contenu
Preface ix

1 Introduction 1

1.1 Geo and chronologies 1

1.2 The ages of the age of the earth 2

1.3 Radioactivity 7

1.4 The objectives and significance of geochronology 13

1.5 References 15

2 Foundations of radioisotopic dating 17

2.1 Introduction 17

2.2 The delineation of nuclear structure 17

2.3 Nuclear stability 19

2.3.1 Nuclear binding energy and the mass defect 19

2.3.2 The liquid drop model for the nucleus 20

2.3.3 The nuclear shell model 22

2.3.4 Chart of the nuclides 23

2.4 Radioactive decay 23

2.4.1 Fission 23

2.4.2 Alpha-decay 24

2.4.3 Beta-decay 25

2.4.4 Electron capture 25

2.4.5 Branching decay 25

2.4.6 The energy of decay 25

2.4.7 The equations of radioactive decay 27

2.5 Nucleosynthesis and element abundances in the solar system 30

2.5.1 Stellar nucleosynthesis 30

2.5.2 Making elements heavier than iron: *s- r-, p-*process nucleosynthesis 31

2.5.3 Element abundances in the solar system 32

2.6 Origin of radioactive isotopes 33

2.6.1 Stellar contributions of naturally occurring radioactive isotopes 33

2.6.2 Decay chains 33

2.6.3 Cosmogenic nuclides 33

2.6.4 Nucleogenic isotopes 35

2.6.5 Man-made radioactive isotopes 36

2.7 Conclusions 36

2.8 References 36

3 Analytical methods 39

3.1 Introduction 39

3.2 Sample preparation 39

3.3 Extraction of the element to be analyzed 40

3.4 Isotope dilution elemental quantification 42

3.5 Ion exchange chromatography 43

3.6 Mass spectrometry 44

3.6.1 Ionization 46

3.6.2 Extraction and focusing of ions 49

3.6.3 Mass fractionation 50

3.6.4 Mass analyzer 52

3.6.5 Detectors 57

3.6.6 Vacuum systems 60

3.7 Conclusions 62

3.8 References 63

4 Interpretational approaches: making sense of data 65

4.1 Introduction 65

4.2 Terminology and basics 65

4.2.1 Accuracy, precision, and trueness 65

4.2.2 Random versus systematic, uncertainties versus errors 66

4.2.3 Probability density functions 67

4.2.4 Univariate (one-variable) distributions 68

4.2.5 Multivariate normal distributions 68

4.3 Estimating a mean and its uncertainty 69

4.3.1 Average values: the sample mean, sample variance, and sample standard deviation 70

4.3.2 Average values: the standard error of the mean 70

4.3.3 Application: accurate standard errors for mass spectrometry 71

4.3.4 Correlation, covariance, and the covariance matrix 73

4.3.5 Degrees of freedom, part 1: the variance 73

4.3.6 Degrees of freedom, part 2: Student's t distribution 73

4.3.7 The weighted mean 75

4.4 Regressing a line 76

4.4.1 Ordinary least-squares linear regression 76

4.4.2 Weighted least-squares regression 77

4.4.3 Linear regression with uncertainties in two or more variables (York regression) 77

4.5 Interpreting measured data using the mean square weighted deviation 79

4.5.1 Testing a weighted mean's assumptions using its MSWD 79

4.5.2 Testing a linear regression's assumptions using its MSWD 80

4.5.3 My data set has a high MSWDwhat now? 81

4.5.4 My data set has a really low MSWDwhat now? 81

4.6 Conclusions 82

4.7 Bibliography and suggested readings 82

5 Diffusion and thermochronologic interpretations 83

5.1 Fundamentals of heat and chemical diffusion 83

5.1.1 Thermochronologic context 83

5.1.2 Heat and chemical diffusion equation 83

5.1.3 Temperature dependence of diffusion 85 <p&gt...