Start Earth dating techniques

Earth dating techniques

The Meishan section in the latter region is accepted as the type locality for the Permian/Triassic boundary.

May 2004 Chuck Roche, Ph D One topic for skeptics involves the age of the earth.

Many creationists have argued for a young earth, one less than 15,000 years, while others allow for just a few million years.

Radiometric dating The process of determining the age of rocks from the decay of their radioactive elements has been in widespread use for over half a century [1].

There are over forty such techniques, each using a different radioactive element or a different way of measuring them.

Geologists have tried various zircon treatments, including abrading the outer surfaces of the crystals, which are typically a tenth of a millimeter across, or leaching the crystals with strong acid.

Despite these treatments, the U/Pb method still produced a wide range of dates for zircons from the same layer of ash.

This is strong evidence that these eruptions caused, at least in part, the global die-off, which some scientists have ascribed to a meteor impact.

Mundil noted that in 1998, one group used U/Pb dating to assign a date of 251.4 million years ago for the main pulse of the Permina extinction, in apparent conflict with the new U/Pb age.

That 'age,' however, "is based on interpretation of a very complicated data set," Mundil said.

Mundil and his colleagues set out to resolve the issue, using a new zircon pretreatment invented by UC Santa Barbara isotope geologist James M. The problem with using microscopic zircons, which are prevalent in volcanic ash, is that the decay of uranium to lead is so energetic that the lead atoms smash through and destroy the zircon crystal structure, which apparently allows some lead to leak out of the crystal, throwing off the analysis.

It has become increasingly clear that these radiometric dating techniques agree with each other and as a whole, present a coherent picture in which the earth was created billions of years ago.