Earth's Hidden Gold Kitchen Discovered Beneath Ocean Floor

Topic: Earth Science

Scientists have found a hidden 'gold kitchen' beneath the ocean floor. Dr. Christian Timm and his team studied volcanic glass samples from the Kermadec island arc and found that gold concentrations are much higher than expected. This discovery helps explain why some regions become rich in gold.

A team of scientists led by Dr. Christian Timm has discovered a hidden 'gold kitchen' beneath the ocean floor. They studied volcanic glass samples from the Kermadec island arc, which is a chain of volcanoes that forms above a subduction zone where one oceanic plate descends beneath another.

The researchers found that gold concentrations in these samples are much higher than expected. In fact, they were several times higher than those found in mid-ocean ridges. This raised the question: what process is responsible for this enrichment?

To answer this, the team measured gold at extremely low concentrations and compared it with other elements like silver, copper, selenium, and platinum. They found that these elements respond similarly during melting, which helps reveal what was happening inside the mantle.

The results indicate that the mantle beneath the Kermadec island arc melts in the presence of water and at relatively high temperatures. This process breaks down sulfide minerals completely, allowing gold to be transferred into the magma. The team also detected original gold concentrations of up to six nanograms per gram of rock, which is unusually high for mantle-derived magma.

The researchers conclude that high-degree, multi-stage melting of a water-rich and oxidized mantle is responsible for the gold enrichment in these magmas.

Why It Matters

This discovery helps us understand how gold is formed and why some regions become rich in it. It also has implications for our understanding of the Earth's interior and the processes that shape our planet.

Key Facts

• Scientists have discovered a hidden 'gold kitchen' beneath the ocean floor, where gold concentrations are much higher than expected.
• The Kermadec island arc is a chain of volcanoes that forms above a subduction zone where one oceanic plate descends beneath another.
• Gold concentrations in volcanic glass samples from the Kermadec island arc were several times higher than those found in mid-ocean ridges.
• The team measured gold at extremely low concentrations and compared it with other elements like silver, copper, selenium, and platinum.
• High-degree, multi-stage melting of a water-rich and oxidized mantle is responsible for the gold enrichment in these magmas.

Key Terms

Subduction zone

A region where one oceanic plate descends beneath another.

Hydrous mantle melting

The process by which water-rich rocks melt to form magma.

Multi-stage melting

The process of repeated melting and crystallization of magma.

Implications

This discovery helps us understand how gold is formed and why some regions become rich in it. It also has implications for our understanding of the Earth's interior and the processes that shape our planet.