Message #258089

[Trasean Trafalgar]

 Taken together, the ages of these fossil corals indicate that we had cored rocks of early-Pleistocene age at the minus 45.0-to-49.5 ft level below current sea-level, there in the middle of the Bimini Inlet. A piece of cemented carbonate silt from the 48.5-ft depth was C-14 dated to 36,100 ±1050 years BP. However, there are clear indications that the reported result represents only a minimum age and that the true age may in fact be older. The measured C13/12 ratio of -5.6 o/oo was more depleted (more negative) than is typical for a sample containing carbonates from a strictly marine environment (typically marine values range from -2 o/oo to +2 o/oo). As such, the C13/12 ratio may be indicating the presence of carbon from post-depositional sources, due to the dissolution, recrystillization, replacement or alteration of carbonates transported by fresh water or rainwater. If that carbon was from younger or even modern (post-1950 AD) sources, the reported radiocarbon age could have easily been biased in the more recent direction by varying amounts.

As an example, consider that if the true age of a hypothetical carbonate rock is, say, 100,000 years, and it contains as little as 1% contamination by post-1950 AD carbon, the C-14 age determination would yield a result of approximately 37,000 years BP. Contamination by younger, but not necessarily modern carbon could also have very large effects depending on the amount and actual age of more recent contaminants contained in the rock.

Therefore, the 36,100-year-old radiocarbon age of the limestone rock at -48.5 ft in borehole 2 is only a minimum age. It provides a "youngest possible" age for the rocks containing the fossil corals identified above. Thus, if the corals at -45 ft and -49 ft represent early to mid-Pleistocene age, then they could be between about 1,800,000 to 400,000 years old. (The "early-Pleistocene" epoch, or the Lower Pleistocene Calabrian epoch to geologists, is represented by rocks between 1.81 to 0.78 million years of age. Mid-Pleistocene age rocks are younger.)

We have examined the stratigraphic implications of all three cores with respect to the probable boundary between the Lower Pleistocene rocks and the overlying, Holocene rocks and sediments. (The Holocene covers the last 10,000 years of Earth history.) If we turn now to the sea-level curve for the late-Pleistocene (Fig. 13) we see that the old land surface of Atlantis could have been above sea level since roughly 120,000 BP.