'Lost City' discovered in Atlantic

A field of volcanic ocean floor chimney stacks, up to 180 feet tall unlike anything seen before, has been discovered in the North Atlantic.

Scientists have named the extraordinary hydrothermal vent system The Lost City, because it sits on a seafloor mountain called Atlantis Massif.

It contains the largest hydrothermal chimneys ever observed.

The biggest vent, named Poseidon, stands 180 feet tall, and towers above previously studied vents which reach 80ft or less.

In other ways, too, the new vents are very different from normal "black smokers".

They are almost 100% carbonate, the same material as the limestone in caves, and range in colour from brilliant white to cream and grey. In contrast, black smoker vents are a darkly mottled mix of sulphide minerals.

The Lost City is situated on 1.5 million-year-old crust and fuelled by vent fluids much cooler than those that accompany black smokers.

The temperature and chemical composition of the fluids are similar to those thought to have existed when the Earth was young.

Scientists have yet to investigate the rich microbial communities living around the vents, which may give new insights into the origins of life on Earth.

The discovery implies that the number of hydrothermal vents on the sea floor may be far greater than scientists previously suspected.

Oceanographer Deborah Kelley, from the University of Washington, who reported the find in the journal Nature, said: "Rarely does something like this come along that drives home how much we still have to learn about our own planet. We need to shed our biases in some sense about what we think we already know."