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This challenge is mainly headed by Creationism which teaches a young-earth (YE) theory.
A young earth is considered to be typically just 6,000 years old since this fits the creation account and some dating deductions from Genesis.
Absolute dating supplies a numerical date whilst relative dating places events in time-sequence; both are scientifically useful.
This is based upon the spontaneous breakdown or decay of atomic nuclei.
The technique gave 90 million years, but took no account of the non-constant erosion rate, or the loss and recycling of salt, or the fact that salt is obtained from other sources as well as continents.
More recently, work has been done on ocean sediments [S. This suggests that, given the current annual rates of erosion (some 27.5 billion tons), all earth's continents would be delivered into the oceans in just 14 million years.
These estimates give 4.4-4.5 billion years for moon rock, and 4.54 billion years for iron metreorites.
These techniques utilize the physical parameters of the earth, such as ice cores, annual lake sediments, and astronomical cycles.
For instance, measurable amounts of C-14 have been found in fossil material, such as coal (traditionally Carboniferous period c300 mya).Mathematically, P = Po exp(-lambda T), where lambda = the decay constant and T = the period of decay. a zero initial number of D atoms, where P(or D) = the current number of P(or D) atoms, it follows that the age of a rock or mineral is computed as T=(1/lambda)ln(1 D/P).Using radiometric techniques, the oldest dated minerals (4.0 - 4.2 billion years) are zircon crystals found in sedimentary rocks in western Australia.One early approach was based upon ocean salinity [John Joly, 1800's].This assumed the ocean was initially pure water and that it's salinity was derived from continental erosion.