Geochemistry

Geochemistry is the science that studies the chemical composition of the Earth and its materials, and the chemical processes that govern the distribution and transformation of elements and isotopes. It investigates rocks, minerals, soils, water, air, and biological materials to understand how elements are sourced, mobilized, and fractionated through geological time and across environments.

Geochemists examine elemental abundances, isotopic ratios, and chemical reactions to reconstruct past conditions and to model current cycles. Major topics include the behavior of elements in the crust and mantle, the oceans and atmosphere, weathering and diagenesis, magmatic differentiation, metamorphism, and sediment transport. Isotopes provide clocks and fingerprints that help date events and trace sources.

Analytical methods include mass spectrometry (ICP-MS, TIMS, SIMS), stable and radiogenic isotope analysis, X-ray fluorescence and diffraction, chromatography, and laser ablation techniques. These tools enable quantitative inventories of elements, partitioning studies, and mass-balance calculations used in models of geochemical cycles.

Geochemistry is interdisciplinary, linking geology, oceanography, atmospheric science, environmental science, and planetary science. Applications range from mineral and energy resource exploration and groundwater assessment to pollution tracing, soil science, climate reconstruction, and understanding planetary differentiation and the evolution of other bodies in the solar system. The field traces its modern foundations to the work of Victor Moritz Goldschmidt in the early 20th century.