Several challenging questions arise from these studies:
1. How is it possible for the relative natural abundance of 87Sr and 86Sr to be virtually the same today as it was 560 million years ago? If the only source of 87Sr in the crust and thus in seawater is the decay of 87Rb, shouldn’t the ratio of 87Sr/86Sr have steadily increased over a half-billion-year-plus timespan?
2. Why do Burke and his co-authors throw away similar-aged samples with low strontium content or high insoluble content in order to obtain tighter clustering of the 87Sr/86Sr ratio?
3. Do the dramatic gyrations of the 87Sr/86Sr ratio better fit catastrophic mixing over a much shorter time interval?
4. The maximum value that the seawater 87Sr/86Sr ratio can reach in this model is 0.720 if contributions only come from sialic (crustal) rocks. Yet, values of 0.748 and 0.930 are observed in modern isochrons constructed from crustal rocks.8,9
5. Finally, stratigraphic dating was apparently used to establish the time frame during which each group of marine deposits was set down. How do we know that a certain rock layer was laid down 100 million years ago? We’re told we “know” how old the rock layer is because of the fossils it contains, and we “know” how old the marine deposits are because of the rock layer they occur in. This is circular reasoning at its clearest and not acceptable science.