Dating middle age
Helens K-Ar dating, and historic lava flows and their excess argon. Yes, scientists are still making minor adjustments. The couple was almost incidental to the deal.
When it is stated that these methods are accurate to one or two percent, it does not mean that the computed age is within one or two percent of the correct age. However, Harland et al imply that nearly the correct value for the branching ratio has been known and used since the mid-fifties. The same question could be asked in general of minerals that are thought to yield good dates. The only correlation I know about that has been studied is between K-Ar and Rb-Sr dating on precambrian rock.
They have proved themselves, they are good at what they do and at the top of their game. She will, unfortunately, become the recipient of sympathy. Unfortunately, Dalrymple says nothing about the calculation of the branching ratio. The rate of diffusion is proportional to the gradient of argon concentration, and increases rapidly with temperature.
If bentonite does not always give correlate and correct ages, this calls into question its use for dating the K-T boundary. Perhaps the earth was made from older pre-existing matter, or perhaps decay rates were briefly faster for some reason. Potassium is found to be very mobile under leaching conditions.
Every woman should have a room of her own. This would be less than one part in a trillion entering the rock each day, on the average. By a combination of diffusion through cracks and channels, and short passages through unbroken regions of the mineral, argon may be able to reach a considerable distance into the mineral. And one of the strongest arguments for the validity of radiometric dating is that the methods agree.
It had been noted that some minerals which yield such dates as beryl, cordierite, etc. Let's also only include rocks which are considered datable by at least one method, since some rocks I believe limestone are considered not to hold argon, for example.
In addition, lava emerging later will tend to be hotter, coming from deeper in the earth and through channels that have already been warmed up. However, Henke admits that this can happen in some cases. Maybe it got included from surrounding rock as the lava flowed upward. This it can do by following the path of the ancient lava flow itself, coming up along the path of the magma.
Unreliability of Radiometric Dating and Old Age of the Earth
Lava that cools underground cools much more slowly, and can form large crystals. This is formed when lava is sticky and bubbles of gas in it explode.
Now, consider an intrusive flow, which cools within the earth. If the minerals in the lava did not melt with the lava, one can obtain an age that is too old. Another factor is that rocks absorb argon from the air. Specifically, he quotes one of his anonymous friends that claims that argon easily diffuses from minerals p.