By looking at the levels of this carbon isotope — known as carbon-14 — in elephant tusks and ivory, researchers can find out how old they are.
(Isotopes are versions of elements that have differing numbers of neutrons in their nuclei.) Knowing the age of elephant tusks is important, since many regulations of ivory trade are date-specific.
To figure out which is the right age, researchers have to sample in two locations on the ivory, said Uno, who performed the research while he was doctoral student at the University of Utah.
After the death of the organism the exchange with the environment stops and also the uptake of Reservoir age The equilibrium ratio is not everywhere the same on earth.
This causes apparent age differences, known as reservoir ages.
In the United States, for example, ivory taken prior to a 1989 worldwide ban on African elephant tusks may be legally traded, while new ivory is illegal to traffic, said Kevin Uno, a researcher at the Lamont-Doherty Earth Observatory at Columbia University in New York.
"I don't necessarily think this will save the elephants, but it's a critical tool to fight poaching of elephants," said Uno, co-author of a study detailing the technique, published today (July 1) in the journal Proceedings of the National Academy of Sciences.
For the remaining period 12,400-26,000 cal yr BP, the curve is derived from independently dated marine samples such as foraminifera and corals.
A new internationally-ratified calibration curve (Int Cal09) covering the whole radiocarbon timescale (~50,000 cal yr) is being prepared by the Int Cal Working Group.For a radiocarbon value measured in a sample S (Fs), bomb radiocarbon delivers two possible calendar dates (T1 and T2), indicated by the grey boxes (Hua, 2009).Details C concentrations are mainly due to variations in the rate of radiocarbon production in the atmosphere, caused by changes in the Earth's magnetic field and variability in solar activity, and changes in the carbon cycle. We test the accuracy of accelerator mass spectrometry radiocarbon dating of 29 herbivore and plant tissues collected on known dates between 19 in East Africa.Herbivore samples include teeth, tusks, soft tissue, hair, and horn.Probiotics are "good" bacteria sold in pharmacies, to be taken alongside antibiotics to protect your intestinal microbiome. How come otorhinolaryngology is a single discipline if it concerns three different body parts? Are there other examples of specialties that include multiple minor subspecialties?