Uranium, lead, and helium in a schematic zircon. 238U decaying to 206Pb releases eight alpha particles (which become helium atoms) within the crystal.


Experiments co-sponsored by the Creation Research Society show that helium leakage deflates radioisotopic ages. In 1982 Robert Gentry found amazingly high retentions of nuclear-decay-generated helium in microscopic zircons (ZrSiO4 crystals) recovered from a borehole in hot Precambrian granitic rock at Fenton Hill, NM. We contracted with a high-precision laboratory to measure the rate of helium diffusion out of the zircons. The initial results were very encouraging. Here we report newer zircon diffusion data that extend to the lower temperatures (100º to 277º C) of Gentry’s retention data. The measured rates resoundingly confirm a numerical prediction we made based on the reported retentions and a young age. Combining rates and retentions gives a helium diffusion age of 6,000 ± 2,000 years. This contradicts the uniformitarian age of 1.5 billion years based on nuclear decay products in the same zircons. These data strongly support our hypothesis of episodes of highly accelerated nuclear decay occurring within thousands of years ago. Such accelerations shrink the radioisotopic “billions of years” down to the 6,000-year timescale of the Bible. (§ is section of reference being cited.)


Under the deep blue skies of northern New Mexico in the fall of 1974, drillmen labored to extract cores from a borehole called GT-2 (Figure 1) nearly three miles deep. The site was Fenton Hill, on the west flank of the Valles volcanic caldera in the pine-covered Jemez Mountains. Two dozen miles to the east, geoscientists at Los Alamos National Laboratory analyzed the drill cores, investigating whether the hot, dry rock would be suitable for providing geothermal energy.

The geoscientists identified the rock as biotite granodiorite, a granitic rock containing shiny flecks of a black mica called biotite. They crushed a core sample from a depth of 2,900 meters and extracted microscopic crystals of zirconium silicate (ZrSiO4) embedded in the biotite. These crystals, called zircons, were radioactive, containing high amounts of uranium and thorium relative to the rest of the rock, as is usual for that mineral. Comparing two isotopes of radiogenic (formed by nuclear decay) lead (206Pb from 238U and 207Pb from 235U), they determined that 1,500 ± 20 million years worth of nuclear decay had occurred in the zirconsassuming as usual that nuclear decay rates have always been constant (Zartman, 1979). The date is consistent with uniformitarian expectations for this Precambrian “basement” rock unit.

The zircons also would be expected to contain helium (4He), which comes from the alpha particles (nuclei of helium atoms) emitted by many of the nuclear decays (Figure 2). This prompted Robert Gentry at Oak Ridge National Laboratory to ask the Los Alamos team to send him core samples from various depths in GT-2 (as well as samples from deeper boreholes nearby). Gentry and his team extracted zircons from the samples, hand-picked crystals between 50 and 75 microns long (Figure 3), and measured the total amounts of helium in them. From the amounts of radiogenic lead in the zircons, they estimated how much helium the nuclear decay should have deposited in the crystals. They found that “an almost phenomenal amount of He has been retained” in the zircons, despite them being small, hot, and allegedly old (Gentry et al., 1982a). Table I shows their results as samples 1 through 6.

Note carefully: Gentry’s large retentions are not what uniformitarians mean by “excess helium” (Baxter, 2003), a common mental pigeonhole into which they shove helium anomalies. In the context of these zircons, “excess” helium would correspond to retentions greater than 100% of the amount nuclear decay could produce in 1.5 Gyr. We are not claiming such “excess” helium at all. As we explain in “Latest results arrive in mid-2003” on page 8 of this paper, the uniformitarian method of “helium dating,” called (U-Th)/He chronometry, is entirely different from the helium diffusion dating we are employing here. Uniformitarian “helium dating” methods would not call attention to the large helium retentions we are concerned with, so it may be that sites like borehole GT-2 are common throughout the world….

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