This dating method is based upon the decay of radioactive potassium-40 to radioactive argon-40 in minerals and rocks; potassium-40 also decays to calcium-40.
Thus, the ratio of argon-40 and potassium-40 and radiogenic calcium-40 to potassium-40 in a mineral or rock is a measure of the age of the sample.
Calcium is one of the essential elements for the growth of most animals.
In this study, in order to evaluate the Ca cycles in the Neoproterozoic, we have measured Ca isotopic ratios () for phosphorite and dolostone ranges from 0.83 to 0.95‰, demonstrating that the fractionation between phosphorite/dolostone and seawater was very small.
Deciphering the drastic changes of surface environment and the emergence of animals after the Neoproterozoic Snowball Earth event are important for understanding the changes of surface environment and its influence on the evolution of life through geologic time.
Especially, the emergence of two types of Metazoan animals such as animal embryo fossils, cnidarians or sponges, and Ediacaran fauna in the late Neoproterozoic was one of the critical turning points in the biological evolution.
The account in Genesis is replete with miracles that do not stand up under rational analysis.
This did not matter; the theological perspective did not require physical rationalization.
On the other hand, the abundance of argon in the Earth is relatively small because of its escape to the atmosphere during processes associated with volcanism.He would have answered that the Earth was ancient, that there had not been a Noachian flood, and that the species of life had not been fixed over the history of Earth.In short, Genesis was an allegory and not literal history.These cosmogonies were part of the new emphasis of science in seeking rational explanations of the features of the world. This period was marked by a great deal of field geology rather than grand cosmogonies.It became clear that there had been significant changes in the Earth's topography over time and that these changes could neither be accounted for by natural processes operating during the brief nor by the postulated Noachian flood.