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WHAT IS THE ACASTA GNEISS COMPLEX AND WHY IS IT SO UNIQUE?

​​​​​​​​​​​Discovered in 1989, the Acasta Gneiss is an outcrop of metamorphic rock dating from the earliest part of the Precambrian Era.

It falls within the Hadean Period, which started with the formation of the Earth 4.6 billion years ago.

It is named after Hades, the Greek god of the underworld and the hellish conditions that prevailed on Earth at the time.

Only a few geological traces from this period remain, with others in Western Greenland and Western Australia. 

The Acasta Gneiss outcrop in Northern Canada is generally regarded as the oldest known intact crustal fragment on Earth.

The minerals at the site are unique due to the high content of silica they contain, which are known as felsic rocks.

The early Earth of around four billion years ago sported a crust that was principally made up of dark-coloured, silica-poor rocks, known as mafic rocks.

A 2018 study suggested that a meteorite barrage around half a billion years after the planet formed at the Acasta Gneiss was responsible for its formation.

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Meteorite strike 4 billion years ago created the oldest rocks on Earth by raising temperatures enough to MELT the planet's crust

Experts from Curtin University, Perth studied a region around the Acasta River, an area scientists have long known that contains rocks that...

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