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What Lies Beneath
May/June 2007
by David Wolman

As a senior scientist in geology and geophysics at the Woods Hole Oceanographic Institution, Henry Dick ’76PhD wants to know what the earth looks like under all that water. Through techniques as simple as dredging for rocks around the world—and as advanced as robotic submersibles that scan the seabed—Dick and his colleagues are redrawing the map of the ocean floor.

Y: What is it that you actually do?

D: I’m a marine geologist and an igneous petrologist—a fire rock doctor. I study the magmas that come out of the ocean floor and the rocks that they come from. The earth is layered: crust, mantle, and core. On the continents, the crust is often up to 30 kilometers thick. But under the oceans, it’s thin. So if you want rocks from the deep earth, oceans are the place to go.

Y: When did you know you wanted to study geology?

D: It goes way back. When I was a boy, my great-grandfather, who also studied geology at Yale, had a rock collection on his farm on the Columbia River in Washington State. As kids, we'd look through it and gather pieces. Geology is a family tradition. And I bit.

Y: What’s it like studying places and phenomena that, unless Titanic director James Cameron loans you a submersible, you’ll probably never get to see firsthand?

D: I don’t need to borrow one. I’ve been down on Alvin—probably the most famous submersible in the world, the one that found the Titanic—two times, and two times on a Japanese submersible. I can tell you that going down four kilometers and tooling around on the ocean floor is just as good as going up in the space shuttle.

Y: Have you ever been up in the space shuttle?

D: No, they haven’t asked me.

Y: Tell me about your most recent research cruise and what you hoped to learn.

D: It was to the mid-Atlantic ridge. We took the remotely operated vehicle Jason, which is a cute little thing, and lowered it down to investigate fault scarps—basically a cliff alongside a fault. We did that because we wanted to look into a deep section of the earth to try and understand its composition.

Y: Is that essentially the $64,000 question that you’re always trying to answer?

D: Yes. When I started in this game 30 years ago, everyone thought they understood the structure of the ocean crust—that it was like a simple layer cake. Now we know that for much of the oceans, it’s not that easy. It turns out that the oceans, rather than being geologically simple, have wonderful complexity. It looks like we’re now only beginning to explore it.

Y: That sounds like a statement right out of a grant application.

D: But it’s true! A few decades ago, a lot of people where thinking that we'd soon be wrapping up most of what we needed to know. But we were parochial in where we went to study: mostly the mid-Atlantic ridge, between Yale and Paris, and the eastern Pacific. That’s where we live and where most of our institutes are located. No one wanted to go to the Southern Ocean or the Arctic, but there are important things to be found in these remote places.

Y: What was your most memorable cruise in the positive sense of the word “memorable"?

D: A cruise to the Gakkel Ridge in the Arctic a few years ago. We went on the Healy, which is a 32,000-horsepower icebreaker owned by the National Science Foundation and the Coast Guard. And they let me drive it. Beforehand, nobody knew whether or not we'd be able to get a single rock off the seafloor of the Arctic Ocean. We successfully dredged 200 times, and came back with an incredible rock collection.

Y: And “memorable” in the negative sense?

D: My first cruise was in 1976. It was 60 days at sea, Buenos Aires to Cape Town, on an Argentine Navy vessel. They had about 100 draftees on board, as well as 30 officers and 20 scientists—on a ship designed to carry 75 people. And there were almost continuous storms. But I did get some good samples.

Y: Does climate change influence geology in any substantial way?

D: It’s the other way around. Geologically, the climate is continuously changing, and a lot of the inputs are geological. The uplift of the Himalaya, for example, has a lot to do with [greenhouse gases such as] carbon dioxide in the atmosphere. The same goes for volcanic activity. When continents move, albeit slowly, that affects climate.

Y: Has President Bush been good to the basic sciences?

D: The weather is really nice here in Falmouth today.

Y: Can you paint a picture as to how scientists a hundred years from now might study marine geology?

D: There’s a general trend to robots and automation. Over my career, as microelectronics have gotten better and smaller, we’ve been moving toward direct observation of the sea floor using autonomous vehicles. On a cruise three years ago, I got a chance to use ABE—the Autonomous Benthic Explorer. It brought back maps of the ocean floor that were like photographs.

Y: Okay, but that sounds like the 10- to 15-year horizon.

D: These things unfold slowly, so I’d say more like 50 years. Fifty years beyond that, I couldn’t tell you. But generally, scientists are increasingly able to study the oceans from their desks. Data is sent in real time from equipment on ships back to desktop computers in offices. That’s a lot better than rolling back and forth in 20- foot waves in the Southern Ocean. But it’s not nearly as romantic.  

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