Radiometric age dating examples
There are many ways to keep track of time, the most reliable of which is to use actual records such as counting hours, days, weeks, and years.However, when we speak of the distant past, there are no historical records and thus no verifiable way to prove that a certain 'date' is correct.What is less commonly known are any of the details of how the issue was settled: such as that the 4.5 billion year 'date' came from a single meteorite that was assumed to be the same age as the earth's core.And since this favored 'date' is the only one that's trumpeted by the media it is the only date that many assume to be correct.And since the earth is not a closed system, these last two assumptions make radiometric dating highly subjective and questionable.
And even though various radioactive elements have been used to 'date' such rocks, for the most part, the methods are the same. This means that if you had some pure uranium-238 with no lead, that 4.5 billion years later, one half of it would have decayed into its stable daughter product (lead-206). Where these alpha particles finally stop, crystal deformation occurs (and) shows up as a discolouration or a darkening of the crystals.
Therefore, in virtually every case, scientists do not know what the original condition of the rock was; and, even if they did know, they don't any more due to heat contamination, mixing, and leaching. Snelling in an article on this topic Note: As for the few cases where scientists do know what the "original" condition (or date of eruption) was, they still have not been able to come up with the correct "date" for the age of the rock without all sorts of fancy footwork and massaging of data.
That's because radiometric dating (with the exception of Carbon 14) is almost always performed on igneous rocks (i.e. Also because, when different substances are in a liquid state, something known as mixing almost always takes place: meaning that whenever a liquid (or molten) rock is erupted out of the earth, both the mother and daughter elements will be "mixed" together, thus making it virtually impossible to determine the time that an eruption took place.
When scientists at the University of Regina, Saskatchewan were asked what the results would be if these roots were dated by Potassium Argon method.
Their response was that the results: Two well-documented examples of "heat contamination" are the 18 eruptions from two Hawaiian volcanoes.The third assumption is that the sample has remained in a closed system.