How black smoke is fuelling the underwater gold rush

Deep in the ocean, hot springs spew plumes of black "smoke" filled with flecks of gold, silver, copper and more.

Today they are just shadows in the water. But eventually, they'll be precious deposits ready to be mined.

Professor Emeritus Steve Scott is one of the few people to see this smokey magic at work. 

He'll share his tales of an under-sea gold rush at a public lecture on Wednesday, May 15, as part of the U of T Science Engagement series, Planet in Focus: From the Frontlines of Geologic Discovery.

Scott spoke with U of T News about his underwater adventures and what he plans to share at his upcoming lecture.

Tell us a bit about your work.
I am an ore deposits geologist who first went to the deep seafloor in 1982 to study how high-temperature hot springs (up to 400°C) make deposits of base and precious metals–copper, zinc, lead, silver and gold–that are mined on land but formed in oceans millions to billions of years ago.

The hot springs are colloquially known as “black smokers” because they look like a dirty industrial process with plumes of fine particulate minerals billowing out of chimney-like structures.

I am the first ore deposits geologist from anywhere and the first Canadian to witness this phenomenon. My students and I have used both occupied and robotic submersibles to water depths of a few thousand metres as well as deep-towed camera and video systems to map and sample the ocean floor.

Most of our work has been in the west, central and northeast Pacific, much of it in collaboration with other research groups. Altogether I have participated in 28 oceanographic expeditions and have been the chief scientist of about half of them. I anticipate that my next expedition will be in the Aegean Sea.

The most spectacular discovery I’ve experienced, made in 1997 with colleague Ray Binns of the Australian government, was in the Manus basin in the southeastern Bismarck Sea off the east coast of Papua New Guinea at 1600 metres water depth. This deposit that now has the name of Solwara 1 is very large and exceedingly rich in copper, silver and gold.

What are the “real world” implications of your research?
The Solwara 1 discovery and others we made in the Manus Basin spawned a new industry of deep-sea mining, potentially worth billions of dollars, when a Canadian headquartered company, Nautilus Minerals, was formed to explore and eventually mine Solwara 1. Other start-up companies have followed.

It is important to note that Binns’ and my work in the Manus was curiosity-driven research. We are not prospectors and yet our work has resulted in the creation of a new and innovative industry.

To us, this is a sterling example of why basic research must be supported, in my case by the Natural Sciences and Engineering Research Council of Canada (NSERC) and by the Bank of Nova Scotia with their first Excellence in Education award. Without such support, Solwara 1 would not have been discovered and subsequent applied research by Nautilus Minerals would not be happening. (Photo by R. Hekinian)

What drew you to this area—and to this particular focus?

I was studying ancient so-called volcanic-hosted massive base and precious metal sulphide deposits in Canada and Japan, and was puzzled by some of the things I was seeing in these ancient ores and their host rocks.

A photograph of the first black smoker ever seen, by French and American scientists published in the November 1979 issue of National Geographic created my eureka moment. I now understood better what the ancient rocks were telling me, so I worked hard to get involved in this nascent seafloor research. My big break came when I was invited to participate in a submersible diving expedition to the Gulf of California led by scientists from Scripps Institute of Oceanography and the Woods Hole Oceanographic Institution in January 1982.

This produced my second eureka moment when, peering out of the observation port of the Alvin submersible at 2000 metres water depth, I saw my first smoker and realized that I was looking at an ore deposit in the making and, furthermore, that such seafloor deposits might become mines of the future.

What drew you to U of T?
I did my PhD in the United States during the Vietnam War. These were difficult times in the USA and my wife and I didn’t want to raise our young family there. The Geology (now Earth Sciences) department offered me an assistant professorship and I accepted, arriving in 1969 a few weeks after my 28th birthday. My research over the past 30 years has required me to be at sea for a few weeks to a couple of months at a time. This was difficult to handle when my expeditions in the western Pacific typically occurred during our academic year but, starting with our department’s chair Geoff Norris in 1982 and continuing ever since, a way was always found for me to go. This support made me very loyal to Toronto. I was head-hunted by other universities but I never accepted.

What is it like to conduct field work?
Field work at sea is very different from what I had been used to on land. I had to learn totally new techniques for doing geology such as dredging, sonar mapping, instrumentation for detecting black smoker plumes, deep-tow photography and video, submersible operations and the like. It is nice to be driven around in an air conditioned ship in the equatorial Pacific with someone making your bed each day and all meals provided but the work days and nights are long and intense. During the first few days if the seas are rough, sea sickness is a problem. It was exciting, though, knowing that I was surveying a place that no one else had ever seen and that my discoveries would live on in posterity.

Can you give us a glimpse of what your Toronto Public Library audience can expect?
I am going to discuss my personal experiences of wonders and mysteries of the deep sea. Very few people know much about the 71 per cent of our planet that is covered by salt water, an area greater than the surface area of Mars plus the Moon times two. I will talk about volcanism and associated hot springs. I will present a geologist’s take on the incredible biology of these sites and what it might mean for life on other planets and potentially habitable moons. I will discuss what mineral resources lay on the seafloor and some of the environmental issues with their recovery.

Your talk is part of the university's Science Engagement campaign. Why is it important to engage the public in science?
Public outreach is an essential task for those of us who have the capability and interesting stories to tell. The public paid my salary and my research expenses so they have the right to know what I found. Too, the general public needs to be educated, at least to some level, in all types of science so they can make informed decisions when important issues arise. Ocean mining is one of those issues.

(Rainbow vent site near the Azores in the Mid-Atlantic Ridge; video by Filipa Marques, Lisbon University)