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The age of the fossil must be determined so it can be compared to other fossil species from the same time period.Understanding the ages of related fossil species helps scientists piece together the evolutionary history of a group of organisms.For example, based on the primate fossil record, scientists know that living primates evolved from fossil primates and that this evolutionary history took tens of millions of years.By comparing fossils of different primate species, scientists can examine how features changed and how primates evolved through time.Conversion of aragonite to calcite leads to errors in dating, resulting in false apparent ages. Because Th dating assumes that all changes in isotope ratios are the result of radioactive decay and ingrowth within a closed system (no chemical/diagenetic shifts in isotope ratios), the effects of recrystallization must be considered. Sturgeon 5.1 Historical Introduction 113 5.2 Mass Bias in MC-ICP-MS 114 5.3 Systematics of Mass Bias Correction Models 115 5.3.1 External Gravimetric Calibration 116 5.3.2 Internal Double-Spike Calibration 117 5.3.3 Internal Calibration (Inter-Element) 117 5.3.4 External Bracketing Calibration (Inter-Element) 117 5.4 Logic of Conventional Correction Models 118 5.5 Pitfalls with Some Correction Models 119 5.5.1 Linear Law 119 5.5.2 Exponential Versus the Power Law 120 5.6 Integrity of the Correction Models 120 5.6.1 Russell’s Law 120 5.6.2 Discrimination Exponent 121 5.6.3 Discrimination Function 122 5.6.4 Second-Order Terms 124 5.7 The Regression Model 124 5.8 Calibration with Double Spikes 126 5.8.1 Caveat of the Model Choice 129 5.9 Calibration with Internal Correction 130 5.9.1 Intra-Elemental Correction 130 5.9.2 Inter-Elemental Correction 130 5.10 Uncertainty Evaluation 131 5.10.1 Uncertainty Modeling and the Double Spikes 132 5.11 Conclusion 133 References 134 6 Reference Materials in Isotopic Analysis 139 Jochen Vogl and Wolfgang Pritzkow 6.1 Introduction 139 6.2 Terminology 140 6.3 Determination of Isotope Amount Ratios 145 6.4 Isotopic Reference Materials 149 6.4.1 General 149 6.4.2 Historical Development 149 6.4.3 Requirements for Isotopic Reference Materials 151 6.5 Present Status, Related Problems, and Solutions 153 6.5.1 Present Status 153 6.5.2 Related Problems 154 6.5.3 Solution 156 6.6 Conclusion and Outlook 157 References 158 7 Quality Control in Isotope Ratio Applications 165 Thomas Meisel 7.1 Introduction 165 7.2 Terminology and Definitions 168 7.3 Measurement Uncertainty 174 7.3.1 Influence Quantities 177 7.3.1.1 Sampling 177 7.3.1.2 Sample Preparation 177 7.3.1.3 Isotope Amount Ratio Determination 177 7.3.1.4 Data Presentation with Isotope Notation 179 7.3.2 Example of Uncertainty Budget Estimation When Using Isotope Dilution 180 7.3.3 Alternative Approach 181 7.3.4 How to Establish Metrological Traceability 181 7.3.5 Method Validation 182 7.3.5.1 Limits of Detection, of Determination, and of Quantitation 182 7.3.5.2 Inter-Laboratory Studies 184 7.4 Conclusion 185 References 185 8 Determination of Trace Elements and Elemental Species Using Isotope Dilution Inductively Coupled Plasma Mass Spectrometry 189 Klaus G.Heumann 8.1 Introduction 189 8.2 Fundamentals 190 8.2.1 Principles of Isotope Dilution Mass Spectrometry 190 8.2.2 Elements Accessible to ICP-IDMS Analysis 194 8.2.3 Selection of Spike Isotope and Optimization of Its Amount 195 8.2.4 Uncertainty Budget and Limit of Detection 199 8.3 Selected Examples of Trace Element Determination via ICP-IDMS 200 8.3.1 Trends in ICP-IDMS Trace Analysis 200 8.3.2 Direct Determination of Trace Elements in Solid Samples via Laser Ablation and Electrothermal Vaporization ICP-IDMS 201 8.3.3 Representative Examples of Trace Element Determination via ICP-IDMS 203 8.3.3.1 Determination of Trace Amounts of Silicon in Biological Samples 203 8.3.3.2 Trace Element Analysis of Fossil Fuels 205 8.3.3.3 Trace Element Analysis via On-Line Photochemical Vapor Generation 207 8.3.3.4 Determination of Trace Amounts of Platinum Group Elements 208 8.3.3.5 Determination of Ultra-Trace Amounts of Transuranium Elements 211 8.3.4 ICP-IDMS in Elemental Speciation 212 8.3.4.1 Principles of ICP-IDMS in Elemental Speciation 212 8.3.4.2 Species-Specific ICP-IDMS 214 8.3.4.3 Species-Unspecific ICP-IDMS 221 References 230 9 Geochronological Dating 235 Marlina A.

Wasylenki 11.1 Introduction 317 11.2 Isotope Ratios of Metals as Paleoredox Proxies 319 11.2.1 Molybdenum Isotope Ratios and Global Ocean Paleoredox 320 11.2.2 Cr Isotope Ratios and Paleoredox Conditions of the Atmosphere 329 11.2.3 Uranium Isotope Ratios and Marine Paleoredox 338 11.3 Diagenesis: a Critical Area for Further Work 344 References 346 12 Isotopes as Tracers of Elements Across the Geosphere–Biosphere Interface 351 Kurt Kyser 12.1 Description of the Geosphere–Biosphere Interface 351 12.2 Elements That Typify the Geosphere–Biosphere Interface 354 12.3 Microbes at the Interface 355 12.4 Element Tracing in Environmental Science and Exploration of Metal Deposits 356 12.5 Isotopes as Indicators of Paleoenvironments 360 12.6 Tracing the Geosphere Effect on Vegetation and Animals 360 12.7 Tracing in the Marine Environment 364 12.8 Future Directions 367 References 368 13 Archeometric Applications 373 Patrick Degryse 13.1 Introduction 373 13.2 Current Applications 375 13.2.1 Lead 375 13.2.2 Strontium 377 13.2.2.1 Inorganics: Glass and Iron 377 13.2.2.2 Organics: Skeletal Matter 378 13.2.3 Neodymium 379 13.2.4 Osmium 379 13.3 New Applications 380 13.3.1 Copper 380 13.3.2 Tin 380 13.3.3 Antimony 380 13.3.4 Boron 381 13.4 Conclusion 382 References 382 14 Forensic Applications 391 Martý´n Resano and Frank Vanhaecke 14.1 Introduction 391 14.1.1 What is Forensics?4) What is the age a granite intrusion which has an isotopic abundance of P=6.25% and a half-life of 4 million years?What percentage of this isotope should be found as daughter material in this rock?Isotope B has a half-life of 7.0 million years and 1.5625% of isotope B is found as parent material. Isotope B has a half-life of 750 million years and 1.5625% of isotope B is found as parent material. The age of a clastic rock would consist of a composite or average age of the igneous and metamorphic rock fragments that make up the rock.Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 95. In exciting progression came discovery of isotopes by J. Thomson in 1912, invention of the mass spectrometer by Dempster (1918) and Aston (1919), the first measurement of the isotopic composition of Pb (Aston, 1927) and the final approach, using Pb-Pb isotopic dating, to the correct age of the Earth: close-2.9 Ga (Gerling, 1942), closer-3.0 Ga (Holmes, 1949) and closest-4.50 Ga (Patterson, Tilton and Inghram, 1953).391 14.1.2 The Role of ICP-MS in Forensics 391 14.2 Forensic Applications Based on ICP-MS Isotopic Analysis 393 14.2.1 Crime Scene Investigation 393 14.2.2 Nuclear Forensics 396 14.2.3 Food Authentication 399 14.2.4 Monitoring Environmental Pollution 404 14.2.5 Other Applications 408 14.3 Future Outlook 411 Acknowledgments 412 References 412 15 Nuclear Applications 419 Scott C. Ketterer 15.1 Introduction 419 15.2 Rationale 419 15.3 Process Control and Monitoring in the Nuclear Industry 422 15.4 Isotopic Studies of the Distribution of U and Pu in the Environment 424 15.5 Nuclear Forensics 429 15.6 Prospects for Future Developments 431 Acknowledgment 431 References 432 16 The Use of Stable Isotope Techniques for Studying Mineral and Trace Element Metabolism in Humans 435 Thomas Walczyk 16.1 Essential Elements 435 16.2 Stable Isotopic Labels Versus Radiotracers 436 16.3 Quantification of Stable Isotopic Tracers 438 16.4 Isotope Labeling Techniques 442 16.5 Concepts of Using Tracers in Studies of Element Metabolism in Humans 444 16.5.1 Overview 444 16.5.2 Fecal Balance Studies (Single Isotopic Label) 444 16.5.3 Fecal Balance Studies (Double Isotopic Label) 445 16.5.4 Plasma Appearance 446 16.5.5 Urinary Monitoring 447 16.5.6 Compartmental Modeling 447 16.5.7 Tissue Retention 448 16.5.8 Element Turnover Studies 449 16.5.9 Isotope Fractionation Effects 450 16.6 ICP-MS in Stable Isotope-Based Metabolic Studies 451 16.6.1 Measurement Precision 451 16.6.2 Mass Spectrometric Sensitivity 454 16.6.3 Measurement Accuracy and Quality Control 454 16.7 Element-by-Element Review 458 16.7.1 Calcium 458 16.7.2 Iron 462 16.7.3 Zinc 464 16.7.4 Magnesium 469 16.7.5 Selenium 471 16.7.6 Copper 474 16.7.7 Molybdenum 476 Acknowledgments 477 References 478 17 Isotopic Analysis via Multi-Collector Inductively Coupled Plasma Mass Spectrometry in Elemental Speciation 495 Vladimir N.