The oldest rock

1992/05/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Geologia

Next to Slave Lake, in Northeastern Canada, a group of North American and Australian geologists have discovered the oldest rocks on Earth.

The weights of the stones found are around 23 kg and the age is 3,960 million years, 500 years younger than the age of the Earth.

According to these researchers, this discovery allows to clarify the darkness that exists on the phase of formation of the Earth.

In order to calculate the antiquity of these stones, several tests have been necessary. The antiquity has been deduced from the analysis of small crystals of zirconium intercaled in the stones.

In order to perform these laboratory tests, it was necessary to use a special equipment located in the Australian Canberra. This equipment is called SHIRMP (Sensitive High Mass Resolution Ion Microprobe) and is based on the radius of zirconium crystals to calculate the age of a stone.

In the following figures you can see, on the one hand, the microscopic structure of these stones and, on the other, the place where they are found.