Untersuchung von isotopenfeinvariationen des calciums in der natur an rezenten carbonaten und sulfaten

Investigations of isotopic variations of calcium were carried out. For that purpose natural calcium carbonate and calcium sulfate samples were analysed. The isotopic ratios ${}^{44}\text{Ca}{}^{40}\text{Ca}$ and ${}^{48}\text{Ca}{}^{40}\text{Ca}$ were measured with a mass spectrometer by thermal ionization. The precision of the isotopic abundance measurements was better than 1%. per mass unit. One can conclude from the results that in general chemical exchange reactions of calcium ions which imply isotopic fractionation do not take place in nature. Only in the case of one sample (‘Gipsrose’) an isotopic variation of calcium was found. This fractionation can be explained by ion exchange or different diffusion rates of the calcium isotopes.