Confirmed: Earth's Oldest Rock In Australia 74
SpamSlapper writes "Australia's ABC Science reports that ancient zircon crystals discovered in Western Australia have been positively dated to 4.374 billion years, confirming their place as the oldest rock ever found on Earth, according to a new study. The research reported in the journal Nature Geoscience, means Earth began forming a crust far sooner than previously thought, following the giant impact event which created the Earth-Moon system 4.5 billion years ago."
Re:Lots of Iron around there (Score:5, Informative)
Not really. The 'Oldest Rock' they're talking about are actually individual mineral grains in a metamorphic rock that used to be sandstone. The zircon sand grains predate the rock they're in by about a billion years. The iron deposts you're talking about come from the same perioid of geologic time as the sandstone.
Re:Amazing! (Score:5, Informative)
I did not know that scientists had examined and dated every rock on (and every rock within) the Earth! The most spectacular part of this task was back when they dismantled Mt Everest, pebble by pebble, examining and dating every little rock, before re-constructing the mountain from all those sorted rocks.
I agree with your general sentiment regarding fake science, however, a little bit of reading comprehension will go a long way.
oldest rock ever found on Earth
It's not like the summary says "The oldest rock on earth!".
Re:Ken Ham issues statement (Score:4, Informative)
I think gp's problem is with this specific type (U-Pb) of dating.
I don't understand how initial values are determined. (Is there some method by which the original ratio of the two elements is known? Or the proportion of radioactive isotopes?)
But, from the wikipedia article [wikipedia.org]
Uranium-lead (U-Pb) dating is one of the oldest[1] and most refined of the radiometric dating schemes, with a routine age range of about 1 million years to over 4.5 billion years, and with routine precisions in the 0.1-1 percent range.[2]
so it does not sound at all un-tested.
While GP is correct that we cannot experimentally confirm the specific mechanisms here (radioactive Pb decay over one million+ years...) , we have a very good description of radioactive decay across the board (table?) and observational results sound extremely consistent. Direct experimentation is not the only form of scientific evidence, despite what [creationist intelligent_designist whatever_nut] might say.