A photo taken on June 11, 2025 shows the crew members with deep sea mining equipment onboard the research vessel MV Anuanua Moana in Rarotonga, Cook Islands. The 1,000-ton ship is exploring the far-flung South Pacific for riches buried beneath the waves, spearheading efforts to dredge the tropical waters for industrial deep-sea mining. The frontier industry is likened by some to a modern-day gold rush, and decried by others as environmental “madness.”

Can you name a single geologic feature of the deep sea?

Take a moment. Think about it. 

Did you pick the Mariana Trench? Odds are pretty good that you did. It is the deepest point on our planet and one of the few places in the deep ocean that most people have heard of.

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The Mariana Trench is not just an isolated spot on the seafloor. This 7-mile-deep column extends into sunlit waters and stretches over 1,500 miles, from Farallón de Pájaros, the northernmost island of the Marianas, to Guam. The geologic structures that make up the trench include the subduction zone, where the Pacific Plate sinks beneath the Mariana Plate at a rate of 1 to 3 inches per year; basins to the west of the trench, where the ocean’s crust buckles and cracks, creating chains of volcanic islands, and an eastern basin, where the Pacific crust is stretched and deformed as it is dragged into the trench, creating a complex network of seamounts and abyssal plain.

The trench lies largely within the U.S. waters of Guam and the Northern Mariana Islands. More than 200,000 people live on its edge. 

On Nov. 12, the Trump administration put out a request for information about the mineral resources in the basin east of the Mariana Trench. This is the first step in a process that could eventually open the region to deep-sea mining — an emerging industry with a

© San Francisco Chronicle