Since the pioneering work of Russell et al. (1978), many
geochemists have applied calcium isotope measurements
to earth science problems. Calcium isotope measurements
have proven useful in geochronologic studies (Marshall
and DePaolo, 1982), especially when comparing the
behavior of argon and calcium (Marshall et al., 1986).
Variation in initial radiogenic calcium-40 can reveal the
fractionation of potassium from calcium during igneous
processes yielding useful information regarding the origin
of ultrapotassic rocks and granites (Marshall and
DePaolo, 1989).
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