And Jack Hills seems to have caught a lot of attention as early as 2006. http://earthobservatory.nasa.gov/Features/Zircon/ and in this article, 4.4B crystal was mentioned. So the actual paper we are reading today is really about using the new technique to confirm the age of the crystal.
"Among the first important discoveries, says Watson, came out in 2001."
Just think about an art from 10, 50, 100, 1000, 5000 and 10,000 years ago. Then think about this 4.4B years ago. It isn't mind-blown; it's scary to think about time. It takes millions of years for rocks to crush into each other and make a planet. What is it like to see things from 4.4B ago? Then think about the galaxy out there. People, the universe is an awesome and scary place.
Here is another article with an image explaining the idea of 4.4B with a personal phone interview from the primary investigator.
http://www.smh.com.au/technology/sci-tech/gem-found-on-austr...
Source: I know John and also do atom probe work.
Also, It was accepted at the end of last year and took a bit to publish, not unusual.
He's an absolutely huge name in the field, and actually treats his students/postdocs very well. He expects a lot in return, but he really does look out for people.
“The reſult, therefore, of our preſent enquiry is, that we find no veſtige of a beginning,–no proſpect of an end.”
— Theory of the Earth, James Hutton, 1788
Anyway there's lots of profit involved, leading to lots of geological research, leading to interesting discoveries.
There are cases ("heavy mineral sands") where zircon is used as an ore, but essentially none of the research on zircons has anything to do with this.
Zircons have a number of nice properties:
1) They contain trace amounts of uranium and (initially) no trace amounts of lead. This allows them to be dated through U/Pb dating, which is relatively precise and is still accurate over _very_ long timescales.
2) They can undergo heating to very high temperatures without allowing lead to escape from the crystal lattice, resulting in the date being "reset". This allows dating of the original zircon grain even after the rock hosting it has gone metamorphism.
3) They're very durable physically and chemically. For this reason, they show up in sedimentary rocks and preserve a record of what was being eroded to produce the sedimentary rocks in question. Even when the sedimentary rocks have been changed into metamorphic rocks, the zircons are often preserved.
4) They're not very rare. Zircon isn't "main" rock forming mineral, but it's a not-too-uncommon accessory mineral in many igneous rocks (mostly in felsic magmas). Because zircons are so durable, they show up in sedimentary and metamorphic rocks sourced from the original igneous rock.
All of these reasons is why you'll see a lot of dating of zircons. They're somewhat common, durable, easy to date, and yield accurate results.
This leads to a lot of uses that you might not think of at first.
For example, if you want to know where (geographically) a given sedimentary rock was sourced from (i.e. what was eroded to form it), the most accurate way is to use the "age spectra" of the zircons within it. You basically disaggregate the rock, sort out the zircons (they're very dense), and date every single grain of zircon (and sometimes many zones on every grain). You take the distribution of ages that you get and compare it to the know ages of large igneous bodies that were likely to be exposed and eroding at the time. By matching the distributions (i.e. mixing models, etc), you can get an estimate of where sediment was being sourced from.
This may sound esoteric, but it's very useful for things like oil exploration.
It has been found a long time ago on Jack Hills. But you are right, somehow, someone, a long time ago, walked on Jack Hills and found a crystal pretty old and started calling for interest.
Although one could argue that the speed things travel through the universe alters their age, but from when the Earth materialized, it shouldn't change much from particle to particle.
If you're arguing for "oldest living thing" I do get it.
By the same definition, I'm not 40 years old either, because practically no part of me is left since I was born.
It's somewhat of a double-standard critique.
Can we all agree that there are a massive number of views on this, and the range between the views is quite a bit closer to continuous than absolute?
For instance, there are those of us creationists who believe in the story of creation as somewhat allegorical, a cultural way of explaining a complex series of events that originated from an intelligent design, possibly including a singularity, evolution, and whatever else might be considered the "anti-creationist" view.
In other words, the zircon grain was found in what was at one point a sedimentary rock (now metamorphosed).
It formed in an igneous rock, was eroded, transported, deposited, lithified, buried, heated up, converted to a metamorphic rock, and then exhumed (actually all of this multiple times).
The zircon survived through all of that. (Which is why there's so much interest in making sure that the U/Pb ratio hasn't been altered by all of the rounds of deformation.)
However, extraterrestrial zircons have been found, and date back even farther.
This is the oldest piece of anything found that we know with reasonable certainty had to come from Earth.
