Tracing mineral reactions using confocal Raman spectroscopy

Abstract

Raman spectroscopy is a powerful tool used to identify mineral phases, study aqueoussolutions and gas inclusions as well as providing crystallinity, crystallographic orientation andchemistry of mineral phases. When united with isotopic tracers, the information gained fromRaman spectroscopy can be expanded and includes kinetic information on isotope substitutionand replacement mechanisms. This review will examine the research to date that utilizes Ramanspectroscopy and isotopic tracers. Beginning with the Raman effect and its use in mineralogy, thereview will show how the kinetics of isotope exchange between an oxyanion and isotopically enrichedwater can be determined in situ. Moreover, we show how isotope tracers can help to unravel themechanisms of mineral replacement that occur at the nanoscale and how they lead to the formationof pseudomorphs. Finally, the use of isotopic tracers as an in situ clock for mineral replacementprocesses will be discussed as well as where this area of research can potentially be applied inthe future.