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Since the tree trunks were entombed in the basalt lava, the wood is thus supposedly at least 30 million years old.Also, what looked like the tree roots were found in the siltstone below the basalt, suggesting the trees when alive were rooted into the siltstone and thus growing on a land surface that was then covered by basalt lava.This was to make sure we at least had some samples of the basalt, just in case permission to have the drill core wasn’t forthcoming.Tiny portions of the same piece of fossil wood encased in the basalt in the drill core were sent for radiocarbon (C) analyses to two reputable laboratories—Geochron Laboratories in Cambridge, Boston (USA), and the Antares Mass Spectrometry laboratory at the Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights near Sydney (Australia).The internationally accepted radiocarbon dating reference is 95% of the activity, in 1950 AD, of the NBS oxalic acid normalized to C activity: » 50 pmc Chemical and isotopc evolution in recharge zone: (Fig) (Fig) Open and closed system conditions ‘real world’ systems are somewhere in between open and closed and the correction models mentioned above and described in Clark and Fritz (chapter 8) have to be applied.magazine has been continuously published since 1978, we are publishing some of the articles from the archives for historical interest, such as this.At approximately four metres (13 feet) thick, the basalt flow is relatively thin, Since the tree trunks were engulfed at the bottom of the flow, cooling may have been immediate, with any water present in the wood aiding extremely rapid encapsulation and thus preservation.
There is also a stable isotope of carbon, C is calibrated against an NBS (National Bureau of Standards) oxalic acid standard.
Potassium-argon (K-Ar) ‘dating’ was performed on the two outcrop samples by the AMDEL laboratory in Adelaide (Australia), while one of the two outcrop samples and two drill core samples, one being in contact with the fossil wood, were ‘dated’ by Geochron Laboratories. When subsequently questioned regarding the limits of the analytical method for the radiocarbon and any possibility of contamination, staff at both laboratories (Ph. scientists) were readily insistent that the results, with one exception, C results (last column in Table 1), consistent with the carbon being organic carbon from wood, and indicating no possibility of contamination.
So the results in Table 1 are staunchly defended by the laboratories as valid, indicating an ‘age’ of perhaps 44,000–45,500 years for the wood encased in the basalt retrieved from the drill core.
I understand how radioactive dating works, but something about it concerns me. If we have a rock and assume that it was 100% carbon-14 at formation, and we now measure it to be 25% carbon-14 and 75% nitrogen-14 (I know nitrogen is a gas, but bear with me), then we can calculate that the rock has been around long enough to pass through 2 half-lives (2 x 5,730 years = 11,460 years). If, in fact, the rock was 50% carbon-14 and 50% nitrogen-14 at its formation, then it would actually be only 5,730 years old (only half the originally calculated age).
This measurement seems to hinge on the fact that we know that the rock was originally 100% carbon-14.