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, Origins 4 2 :68-75, 1977 Webster, C.

Dickin Radiogenic Isotope Geology, 1995, p.

As time passed, this Ar40 would gradually pass into the atmosphere, reducing this effect and making rocks appear younger.

This shows that excess argon is entering these rocks by some means, and calls K-Ar dating into question.

A discussion of rubidium-strontium ages in the Isotope Geoscience Section of the journal, Chemical Geology, specifically states that a radioisotope age determination "does not certainly define a valid age information for a geological system.

The Cambrian period is conventionally assumed to have begun about 550 million years ago.

As a first approximation one can assume this, but more accurate results must take into account fluctuations in the intensity of the cosmic rays entering the Earth's atmosphere.

26 32 32 1:1 2 2.

He states that the number of dates within range are less than the number of anomalies, except for the Cenozoic and Cretaceous.