46
B. Fractionation Mechanisms of Selected Elements
4. Calcium
Calcium has six stable isotopes in the mass-range of 40 to 48
(BACKUS et al., 1964):
40Ca:
96.88 % ,
42Ca:
0.655% ,
43Ca:
0.138% ,
44Ca:
2.12% ,
46Ca:
0.0046% ,
48Ca:
0.20% .
Several authors achieved reproducibilities of around 1 % in the measurement of the 48CarCa ratios (HIRT and EpSTEIN, 1964; STAHL, 1968;
STAHL and WENDT, 1968; LETOLLE, 1968; CORLESS, 1968). Although a
great variety of biological and geological samples were measured, no
variations in calcium isotopic composition were found.
Although the stable isotope geochemistry of calcium might reveal
very interesting aspects of calcium, we need more sophisticated techniques to investigate these.