Scientists discover fragments of Earth’s primitive crust in Australia

Researchers at Curtin University in Australia It had access to parts of the Earth’s ancient continental crust. The age and composition of these primitive rocks “have been derived from indirect isotopic modeling or through detrital minerals” [que se originam da desintegração física e decomposição química] in the upper basins,” the study says.

These examples The age of our planet, close to 4.5 billion years old, was detected near the city of CollieOne of Western Australia’s main coal mining regions. This suggests that the country’s ancient rocks cover a much larger area than those traditionally studied at the Murchison site, more than a thousand kilometers away.

The continental crust is a relatively thin layer of the planet compared to others, but it is fundamental to geology and life on Earth as it supports ecosystems as well as the base of the continents and some areas of the continental shelf. and providing resources such as fresh water for civilization.

primitive shore of the world

Much of the Earth’s primordial crust is buried very deeply or has been chemically altered over time. Only a few open areas can be directly observed by researchers. That’s why scientists use indirect observation methods to analyze weathered and preserved minerals.

In the current study, published in the journal Communications Earth & Environment, the authors “drag” small amounts of minerals from the depths and transported them to the surface via trenches. Dark finger-like magma structures in the Earth’s mantle extending to a depth of approximately 50 kilometers.

How did researchers date the remains of primitive crust?

While searching for traces of ancient rocks, the authors dated crystals of zircon, a mineral extremely resistant to chemical and physical changes, and also contained traces of uranium that turned into lead over time. Meticulous measurement of this lead-to-uranium ratio makes it possible to discover when the grain has crystallized.

Although some dyke crystals have lost their isotopic records, most are encapsulated in a mineral called titanite (or sphene). It is even more durable than zircon. Armored in this way, these grains provided a valuable clue to the beginning of Earth’s history; In this case, it is estimated at 3.44 billion years.

The 1.4 billion-year-old dam, also dated, allowed an unprecedented “window to be opened” that would have remained hidden were it not for its armored zircons. This result extended by several million years what was previously considered the oldest area of ​​the Earth’s crust, the record of which belonged to the Narryer area in the Murchison region.

At TecMundo, always stay informed about the latest research on the evolution of planet Earth. If you wish, take the opportunity to learn more about the world’s largest asteroid crater located in Australia.