Potassium 40 dating problems
Possible other sources of correlation Anomalies of radiometric dating Why a low anomaly percentage is meaningless The biostrategraphic limits issue Preponderance of K-Ar dating Excuses for anomalies Need for a double-blind test Possible changes in the decay rate Isochrons Atlantic sea floor dating Dating Meteorites Conclusion Gentry's radiohaloes in coalified wood Carbon 14 dating Tree ring chronologies Coral dating Varves Growth of coral reefs Evidence for catastrophe in the geologic column Rates of erosion Reliability of creationist sources Radiometric dating methods estimate the age of rocks using calculations based on the decay rates of radioactive elements such as uranium, strontium, and potassium.
On the surface, radiometric dating methods appear to give powerful support to the statement that life has existed on the earth for hundreds of millions, even billions, of years.
In these materials, the decay product Ar is able to escape the liquid (molten) rock, but starts to accumulate when the rock solidifies (recrystallizes).
The amount of Argon sublimation that occurs is a function of the purity of the sample, the composition of the mother material, and a number of other factors.
These factors introduce error limits on the upper and lower bounds of dating, so that final determination of age is reliant on the environmental factors during formation, melting, and exposure to decreased pressure and/or open-air.
Time since recrystallization is calculated by measuring the ratio of the amount of The quickly cooled lavas that make nearly ideal samples for K–Ar dating also preserve a record of the direction and intensity of the local magnetic field as the sample cooled past the Curie temperature of iron.
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So, when a mineral forms – whether from molten rock, or from substances dissolved in water – it will be initially argon-free, even if there is some argon in the liquid.
However, if the mineral contains any potassium, then decay of the K isotope present will create fresh argon-40 that will remain locked up in the mineral.
This gives us the impression that all but a small percentage of the dates computed by radiometric methods agree with the assumed ages of the rocks in which they are found, and that all of these various methods almost always give ages that agree with each other to within a few percentage points.
Since there doesn't seem to be any systematic error that could cause so many methods to agree with each other so often, it seems that there is no other rational conclusion than to accept these dates as accurate.