Dating on earth release
“Our job is not just to measure the isotope composition of the inclusion, but also to get the whole picture of how the diamond formed, before we end up destroying the diamond to get the inclusion out.” The first step is to slice the diamond very precisely across its growth zones using a diamond-cutting laser.
If scientists know the rate of radioactive decay, and have instrumentation capable of measuring the different isotopes present, they can calculate the age of an item very accurately.
We’ve traveled to the Carnegie Institution of Washington—more specifically the Institution’s Department of Terrestrial Magnetism—to document Dr.
Shirey’s work on determining the age of diamonds from many mines around the world by analyzing the tiny mineral inclusions preserved within them. Steven Shirey, a senior scientist at the Carnegie Institution of Washington’s Department of Terrestrial Magnetism, has a special interest in diamond—it’s his best method of glimpsing the unimaginable pressures and temperatures of the deep earth’s interior.
This sharp-edged octahedral diamond crystal nestles in kimberlite, the rock that brought it to the earth’s surface. Not merely for their intrinsic beauty, but for the fundamental information locked within them.
Such crystals may preserve minerals from deep in the mantle and provide a record of temperature and pressure conditions there. Information that illuminates the earth’s early history and the planet’s structure at depths hundreds of kilometers beneath our feet.His particular specialty involves seeking out the rare individual diamonds that contain tiny and specific sulfide inclusions, painstakingly removing the inclusions and analyzing their contents—in this case, trace amounts of the radioactive isotopes of the rare metals osmium (Os) and rhenium (Re)—to determine ages on the order of billions of years.