Book contents
- Frontmatter
- Contents
- Preface to the second edition
- Preface to the first edition
- Preface to the English edition
- 1 Heat from within
- 2 At the time of the Earth’s birth
- 3 Formation of the layered structure of the Earth
- 4 Time scale of the Earth’s evolution
- 5 Plate tectonics revolution
- 6 Evolution of the mantle
- 7 Origin of the atmosphere and oceans
- 8 Isotopes as DNA of nature
- 9 The Earth’s magnetism
- 10 The Moon
- 11 The past and future of the evolving Earth
- References
- Index
8 - Isotopes as DNA of nature
Published online by Cambridge University Press: 05 May 2012
- Frontmatter
- Contents
- Preface to the second edition
- Preface to the first edition
- Preface to the English edition
- 1 Heat from within
- 2 At the time of the Earth’s birth
- 3 Formation of the layered structure of the Earth
- 4 Time scale of the Earth’s evolution
- 5 Plate tectonics revolution
- 6 Evolution of the mantle
- 7 Origin of the atmosphere and oceans
- 8 Isotopes as DNA of nature
- 9 The Earth’s magnetism
- 10 The Moon
- 11 The past and future of the evolving Earth
- References
- Index
Summary
NON-RADIOGENIC STABLE ISOTOPES
In the preceding sections, we have shown how isotopes play an important role in tackling a variety of problems concerned with tracing the Earth’s evolution, with an emphasis on radioactive isotopes as a unique time marker. Let us recall, for example, that argon consists of three isotopes argon-36, argon-38, and argon-40, all of which are stable isotopes. Argon-40 is a radiogenic stable isotope, and its amount increases with time through the radioactive decay of potassium-40. The other two isotopes of argon are non-radiogenic stable isotopes, and their abundances have not changed since their birth in a star. We have discussed radiometric geochronology, in which the amount of a radiogenic stable isotope such as argon-40 yields an absolute time marker of rock or mineral formation age.
Here, we turn our attention to the use of non-radiogenic stable isotopes as a tracer of geochemical processes in nature. Thanks to the recent development of microchemical analysis of elements, systematic variations in the ratios of non-radiogenic stable isotopes, albeit extremely subtle, yield a unique means to entangle extremely complicated geochemical cycles of elements. Let us see how this becomes possible.
- Type
- Chapter
- Information
- The EarthIts Birth and Growth, pp. 95 - 103Publisher: Cambridge University PressPrint publication year: 2012