An analogous process exists in seawater, wherever 44Ca/40Ca has a tendency to rise when the speed of removal of Ca2+ by mineral precipitation exceeds the input of new calcium in to the ocean. In 1997, Skulan and DePaolo offered the primary evidence of change in seawater 44Ca/40Ca around geologic time, https://trentonpnicy.frewwebs.com/28689795/the-2-minute-rule-for-toxic-hazardous-waste-in-santa-ana