银同位素在行星和地球科学中的研究进展

Accurate Determination of Silver Isotopic Composition in Silicate Rocks with Low Silver Abundance

“…In recent years, the demand for gold and silver has increased sharply. Gold and silver occur mainly as native gold or native silver in ore deposits, but silver may also occur as sulfides, acanthite and argentite, and with gold in more complex minerals containing other elements. ,,, Several studies have shown that both gold and silver are highly soluble as bisulfide and chloride complexes in hydrothermal systems. ,,− The similarity of the chemical properties of gold and silver makes δ 109 Ag an ideal tool for quantitatively evaluating the formation of mineral deposits involving gold …”

“…During early research, silver isotopic compositions were particularly useful in studying volatile depletion in the early solar system because the extinct radionuclide 107 Pd decays to 107 Ag (half-life of 6.5 Ma) . The Pd–Ag chronometer has been successfully applied to study core formation and volatile-element depletion processes in the early solar system. ,− More recently, with an improved understanding of the fractionation mechanisms of silver isotopes in processes affecting the environment, δ 109 Ag values have been applied as a sensitive tool to track the sources and paths of migration of silver contaminants. − The narrow range of δ 109 Ag silver isotope ratios in silver coins from different periods − and minimal metallurgical isotopic fractionation make silver isotopes excellent recorders of the provenance and circulation of past silver coinages. ,− In contrast, the range of δ 109 Ag values of silver ore deposits is much greater (δ 109 Ag = −1.0 to +2.3‰). − Studies related to the genesis of polymetallic mineral deposits have indicated no systematic δ 109 Ag variation with the age of mineralization, deposition temperature, deposit type, or the nature of the source rocks . Instead, physicochemical processes related to silver transport and deposition control silver isotopic fractionation during ore formation, ,,− which allows for δ 109 Ag to be applied to the study of the genesis of base and precious metal deposits and in their exploration. − , …”