Three assumptions of radiometric dating metro radio dating co uk
And since the earth is not a closed system, these last two assumptions make radiometric dating highly subjective and questionable.
For example, if a rock sample was below the water table at any time, leaching would take place.
This is because "common" lead contains both radiogenic (lead 206, 207 and 208) and non-radiogenic lead (204) but it does not contain any uranium.
In fact, about 98% of common lead is "radiogenic" (containing lead 206, 207, 208) and only 2% non-radiogenic.
However, not as well known is the fact that such methods have serious flaws which are often glossed over, or ignored when writing on, or discussing this subject in public. that (the) half-lives (of uranium-thorium-lead) are not constant but vary with time. comes from the study of pleochroic haloes which form in a rock in the following way.
Another pertinent thing that's also ignored, minimized, or scoffed at are the numerous other scientific methods of dating the earth, solar system, and or universe that yield much younger ages than 500 million years (max). When a rock crystallises, the crystals of the minerals in the rock often enclose minute grains of other minerals which contain uranium and thorium.
Another problem that calls into question the credibility of radiometric dating is heat contamination.
For example, In 1973, in Alberta, Canada (near the town of Grand Prairie) a high voltage line fell which caused nearby tree roots to fossilize almost instantly.
Few people realize it but all radiometric dating methods require making at least three assumptions. Now the magnitude of the radius of a pleochroic halo in a particular mineral depends on the amount of energy that the alpha particle has ... depends on the half-life of the particular decay responsible for this alpha particle emission.
This proves that the half-lives of the uranium and thorium radioactive decays vary ... any age determination using this method of dating will be inaccurate because it is based on an invalid assumption." " ... For example, discordant dates have been obtained on the same rocks by ...
can we be sure the U and Th have always decayed at the same rates we measure today? (various) Given ample evidence observable in the present that decay rates have not been constant throughout the supposed deep time, it is not reasonable to assume they have been uniform through unobservable eons.
With the exception of Carbon-14, radiometric dating is used to date either igneous or metamorphic rocks that contain radioactive elements such as uranium. Now when the uranium or thorium disintegrates, the alpha particles which are emitted are slowed down by the crystals in which the grains of the uranium- or thorium-bearing minerals are embedded.
And even though various radioactive elements have been used to "date" these rocks, for the most part, the methods are basically the same. This means that if you had some pure uranium-238 with no lead in it, 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.