This is evidently a paper using the data from multiple sources and analyzing the whole.
Here is an example cited from the paper.
Most of their foraminifera were from a Pleistocene core from the tropical Atlantic off the northwest coast of Africa dated at 455,000 years. The foraminifera from this core showed a range of 14C values from 0.16 to 0.4 pmc with an average, taken over 115 separate measurements, of 0.23 pmc. A benthic species of foraminifera from another core, chosen because of its thick shell and smooth surface in the hope its ‘contamination’ would be lower, actually had a higher average 14C level of 0.58 pmc!
The authors then performed a number of experiments involving more aggressive pre-treatment of the samples to attempt to remove contamination. These included progressive stepwise acid hydrolization of the carbonate samples to CO2 gas and 14C measurement of each of four separate gas fractions. They found a detectable amount of surface contamination was present in the first fraction collected, but it was not large enough to make the result from the final gas fraction significantly different from the average value. They also leached samples in hydrochloric acid for two hours and cracked open the foraminifera shells to remove secondary carbonate from inside, but these procedures did not significantly alter the measured 14C values.
The authors summarize their findings in the abstract of their paper as follows, “The results…show a species-specific contamination that reproduces over several individual shells and foraminifera from several sediment cores. Different cleaning attempts have proven ineffective, and even stronger measures such as progressive hydrolization or leaching of the samples prior to routine preparation, did not give any indication of the source of contamination.” In their conclusion they state, “The apparent ages of biogenic samples seem species related and can be reproduced measuring different individuals for larger shells or even different sediment cores for foraminifera. Although tests showed some surface contamination, it was not possible to reach lower 14C levels through cleaning, indicating the contamination to be intrinsic to the sample.” They continue, “So far, no theory explaining the results has survived all the tests. No connection between surface structure and apparent ages could be established.”
The measurements reported in this paper obviously represent serious anomalies relative to what should be expected in the uniformitarian framework. There is a clear conflict between the measured levels of 14C in these samples and the dates assigned to the geological setting by other radioisotope methods. The measured 14C levels, however, are far above instrument threshold and also appear to be far above contamination levels arising from sample processing. Moreover, the huge difference in 14C levels among species co-existing in the same physical sample violates the assumption that organisms living together in the same environment should share a common 14C/C ratio. The position the authors take in the face of these conflicts is that this 14C, which should not be present according to their framework, represents ‘contamination’ for which they currently have no explanation.
Contamination by excess 14C should make the item appear to be younger that it really is. If it is not contamination then it is younger than whatever method considers it older.