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So this is a diagram showing you a diamond plate.
And this is a cathodoluminescence image
of a diamond.
And different color represents the concentration
of a nitrogen in different regions.
You can see a multi-growth pattern of the diamond
with a variation of the nitrogen in the diamond.
And we can use the ion probe to measure,
say, carbon isotopes in different regions,
using a spot.
The spot size is about 15 microns, 15 micrometers.
And you can see the variation of carbon isotopes.
And we can use in a different session
to measure nitrogen isotopes and the nitrogen concentrations
in different areas.
And these are the nitrogen isotopes composition
and the nitrogen concentration in different areas.
So from this information, if we see a variation of the, say,
carbon isotopes, if it changes a lot,
we can infer it was formed at a different carbon source,
from different carbon source.
If it's, say, in this case, all the carbon are from the mantel.
So it's very close to the primordial composition
of the mantel carbon isotopes.
In some cases, if you see, say, a very negative carbon isotope
composition, say, minus 24.
Most the cases, these carbon are from the organic origins.
So they might be coming from the surface of the Earth.
So could indicate the subduction of a mantle of oceanic
across from the surface under, into the mantle,
deep into the mantle.
This technique can show you how the carbon is in a diamond,
was came from, whether it's from the top,
from the surface of the Earth, or whether it's originally
from deep mantle origin.
Yes.
Our recent research paper, 2012 paper
we measured diamonds from Brazil.
And we found out some diamonds had a very strong signature
of the organic origin.
But the inclusions, some of the inclusions in the diamond, we
found they were formed very deep in the mantle.
It's like 800 kilometers deep from these inclusions.
We can infer that the source is from the surface,
from the Earth's surface.
And but they formed deep in the mantle.
So that tells us that the subduction went all the way
down to the deep mantle and the kimberlite.
So when after the diamond was formed,
they brought up from the kimberlite and to the surface.
So the diamond tells us the history
of the carbon coming from the surface, went down
to the mantle, formed the diamond,
and the kimberlite brought them up to the surface.
So we've got the diamond and measured them in this lab.
He was doing the measuring the sulfide composition
in the diamond to find out the age of the--
when the diamond was born.
So yeah.
It's a collaboration between other people
to get this research result.
It's a whole story of how the Earth's subduction works.
Yeah.