Here, time is measured in milligrams. Under a microscope, a lab technician cleans a tiny wood chip extracted from an American museum treasure. This fragment no bigger than a fingernail is enough to divine whether the artefact it came from is really the Roman musical instrument its owners believe it to be.
Gns water dating lab manager Dr Christine Prior already has bad news for another client — an art authenticator in Hong Kong. The drinking vessels made from rhino horn she sent for radiocarbon dating turned out to be modern fakes.
Although little-feted, GNS's Rafter Radiocarbon laboratory in Lower Hutt was among the world's first to use radioactive decay to unravel history. Set up init remains the longest-running.
Prior runs the half of the laboratory that cleans and distils samples down to pure elemental carbon, or graphite.
It's that radioactive form of carbon — known as C14 — that is the key to discovering whether a carved ivory sculpture is an antiquity or a modern sham feeding poachers' coffers; whether a water bore is sucking dry an age-old aquifer or tapping a renewable store; whether a picture frame predates the painting in it. Prior planned to be a "regular scientist", like Gns water dating lab aerospace engineer father.
But as a little girl her parents took her to the archaeological sites of Colorado's Mesa Verde. At university she took some anthropology classes to find out what those ruins were really all about. Then she got hooked.
They radiocarbon dated it and it came out as a couple of thousand years old.
You could see there was the impression of somebody's toes. You could see they had worn it and the straps were not there any more and you could just imagine somebody going Gns water dating lab not wearing these one more day — I need new shoes' and flinging it to the back of the cave. It is somebody's sweaty little footprints right there and all of a sudden, you feel like you're there years ago.
These days Prior rarely gets to hold the objects her team is dating. Often they will get photos of the bigger item to place the tiny samples in context. Sometimes Prior will get to take the sample herself, getting buzzed up to an exclusive London showroom to remove a single fibre of an ancient textile crafted by a group of women years ago, "needles flashing, gossiping away". Every sample tells a story. Sometimes it's a story nobody is expecting. When Canterbury Museum radiocarbon dated one of its mummies and her sarcophagus it discovered that the coffin was much older than its contents.
And when an ivory artefact submitted by an American conservator came out at 10s of thousands of Gns water dating lab old — an impossibility for human art — Prior fretted that they had somehow contaminated the process.
The conservator, however, was not angry at the result. As the Arctic ice sheets melt, the Siberian tundra is being exposed, together with preserved mammoth tusks, which are then carved and sold as ivory antiques. Radiocarbon dating was invented by American Willard Libby in the late s. It uses the presence of radioactive carbon 14 in living things to deduce the age of old objects.
When something is alive, its ratio of C14 to the two stable forms of carbon, C12 and C13 is in harmony with its environment. when it dies, the radioactive C14 begins to decay, while the levels of C12 and C13 remain constant.
And that is all radiocarbon dating is," Prior says matter-of-factly. The devil, of course, is in the detail. To get an accurate date you have to know how much C14 the organism had in the first place and how C14 levels in the atmosphere have changed over time. The way scientists achieve that is by radiocarbon dating things they know the age of — trees. By dating the rings of ancient tree trunks they have created a continuous chain of data going back more than 10, years.
Radiocarbon daters must be the Gns water dating lab people who are about the world's foray into nuclear bombs and testing. While radiocarbon dating of more modern objects can be problematic, the so-called bomb peak allows scientists to quickly separate ancient and modern.
There is serious money at stake here. But that is small fry to art collectors and dealers. Prior remembers a run of angry customers when a bunch of beautifully embroidered Chinese textiles from the warring states period about BC were exposed as modern. It turned out that an old exhibition catalogue had made its way back to China where forgers had replicated exactly the styles and motifs.
Prior also uses the bomb peak to find out whether Australian groundwater samples, which make up much Gns water dating lab the lab's work, are from ancient aquifers or from water sources being regularly recharged. While the Aussies are hoping their water will be young as it means it's a Gns water dating lab resource, when a Nelson vodka company dated its water source some years ago it was hoping for an ancient date — the 26, years from which it takes its name.
In the early days, radiocarbon dating was painfully slow as it involved waiting for the C14 to decay and counting the rate.
If the sample was very old and contained little C14, that process could take weeks. The samples also needed to be huge. To test the age of a fire in an archaeological dig, for example, great lumps of charcoal would be pulled from the hearth.
Today, Prior can test an individual seed from that same fire and it will be among 25 samples processed every second day. The key is that hulking machine down the corridor — the accelerator mass spectrometer that GNS bought in Gns water dating lab much of her work involves dating samples for geologists, marine biologists or earthquake scientists, Prior remains an archaeologist at heart.
But "Gns water dating lab" does not regret her decision to be a lab rat. I just thought that studying the artefacts in a nice air-conditioned laboratory had a lot of appeal. When Te Papa framer Matthew O'Reilly discovered a woodworm-ravaged frame in the museum's store he had a fair idea which painting it belonged to.
But O'Reilly could tell the frame was much older and did not appear to be either French or English. By radiocarbon dating a chip of wood from the frame he was able to confirm his suspicions — the artist must have used a recycled or "found" frame as the intricately carved border dated from the mid 17th century. That knowledge also told him something about the painter.
The reason the frame was replaced by an overzealous staff member — its poor condition — was probably the same reason Lamb chose Gns water dating lab in the first place.
This frame is perfectly deployed for something that is about decay. In 19th century Egypt the market for mummies was hotting up. Mummies in matching sarcophaguses fetched a higher price than the bare linen-wrapped forms, so some unscrupulous dealers found empty but unrelated homes for their mummies.
That was one explanation considered by Canterbury Museum anthropology curator Roger Fyfe when radiocarbon dating of the museum's Tash pen Khonsu mummy and her sarcophagus turned up a vexing result. Egyptologists thought the mummy dated from about BC so there were no surprises when a sample of her linen wrapping came back with an estimate of BC.