Joel Kontinen
Researchers at the Queensland University of Technology warn of trusting zircon dating uncritically and trusting assumptions that might well be wrong.
An article posted at Phys.org says:
" 'One of the assumptions being made is that the composition of the zircons and the rocks in which they have formed give an accurate record of the magmas and conditions at which the zircons and magmas formed,' Associate Professor Bryan said.
From this, we then estimate the age of the event that caused them to form.”
This might give dates that are off by millions of years:
"Some zircon crystals may not be related to their host rocks at all. They may have come from the source of the magma deep in the Earth's crust or they may have been picked up by the magma on its way to the surface.”
A similar problem might skew dates obtained by other dating methods as well.
Source:
Phys.org. 2017. Zircon as Earth's timekeeper: Are we reading the clock right? (23 October).
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