Knowra Isotope geochemistry Isotope geochemistry Isotope geochemistry studies variations in isotope abundances in geological materials to investigate Earth processes, material origins, and geological history.
Isotope fractionation : A change in isotope ratios caused by differences in how isotopes participate in physical, chemical, or biological processes. Fractionation creates systematic isotope differences that reveal processes such as evaporation, mineral growth, and metabolism.
Radiometric dating : A method for determining age from measured radioactive decay and isotope abundances. Radioactive isotope systems provide numerical ages for rocks and geological events.
Isotope : One of two or more atoms of the same element with different numbers of neutrons. Isotopes are the distinct atomic forms whose abundances isotope geochemistry compares.
Age of the Earth : The time elapsed since Earth formed, estimated at about 4.54 billion years. Radiometric isotope measurements of meteorites and ancient minerals underpin this estimate.
Initial strontium ratio : The strontium isotope ratio of a geological material at the time it formed, reconstructed from its later composition and age. Its value depends on assumptions about age, alteration, and parent-to-daughter evolution.
Radiogenic isotope : An isotope produced by the radioactive decay of a parent nuclide. Radiogenic daughter isotopes accumulate in minerals and trace radioactive histories.
Uranium–lead dating : A radiometric dating method based on decay of uranium isotopes to lead isotopes. Zircon uranium–lead ages often constrain the formation and later history of ancient rocks.
Radioactive decay : The spontaneous transformation of an unstable atomic nucleus into another nucleus, often with emitted particles or radiation. Decay changes parent and daughter isotope abundances in predictable ways.
Great Oxidation Event : A major rise in atmospheric oxygen around 2.4 billion years ago, recorded by geological and geochemical evidence. Sulfur isotope anomalies in ancient rocks help constrain the transition in atmospheric chemistry.
Lead–lead dating : A radiometric dating approach that uses relationships among lead isotope ratios to estimate ages. Its interpretations depend on how lead evolved and mixed in the sampled system.
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