This week, “A Fresh Eye” welcomes one of Oxford University’s well-loved figures, geologist Stephen Moorbath. A lifelong geochemist and field researcher, he spent three decades of summers on Greenland. He played a pivotal role in the discovery and analysis of the very oldest rocks on earth. He’s also well-known (some might say notorious) for his deft and daft way with words, as you’ll soon discover.
Q: Welcome, Stephen. As a young boy in England, what adventurous thing did you dream of doing or becoming?
A: As a small boy, I wanted to be a tram-driver. I used to stand next to them for years in my daily travels. It built my character; and it was there that I learned how to read between the lines!
Q: Did you achieve your goal?
A: I never became a trolley-car operator; but some years later at school, I fell in love with the science of chemistry, producing some nasty little fires and explosions in our kitchen. Although I was actively discouraged from this activity, I later enrolled at Oxford U. to study chemistry. With chemistry, I really felt in my element (or all 92 of them). However, during my first year, I underwent a sudden conversion to geology—the best thing I ever did. In any case, geology involves a lot of chemistry; in fact, the distribution of the chemical elements in nature is called “geochemistry.” I’m actually a fully paid-up “geochemist.”
Q: What won you over to geology?
A: The main reason I wanted to study it? The geological sciences provide such a wonderful and truthful picture of the origin, evolution, and structure of our planet throughout the whole of geological history—and of the evolution of all living creatures inhabiting the planet. All this is so much more realistic and intellectually satisfying than the picturesque but totally inaccurate creation myths of religious texts.
Q: Who have you principally worked for, in this field?
A: After years of study I became a university academic, involved mainly in teaching and scientific research. I’ve spent most of my professional life at Oxford University, which happens to be one of the places where modern science began some 400 to 500 years ago. And shows no sign of ending yet!
Q: Stephen, what’s the most important find you’ve ever made?
A: I’ve found many interesting geological and archaeological objects, but the most important may have been my close connection with the 1971 discovery of the oldest known rocks on the earth’s surface—and actually holding them in my hands.
Q: Wow. Tell us more about this.
A: I first visited Greenland in 1957, as a geological field assistant to an expedition. My own research work there started in 1971. I worked closely with Vic McGregor (now deceased) in the discovery of the oldest known rocks and the measurements of their actual age—close to 3.8 billion years. This is still quite a bit younger than the age of the earth itself (and of the solar system), which is close to 4.5 billion years. I spent 15 summers on Greenland (1971 – 2001), collecting rock samples, which were then transported to Oxford for geological and chemical research. The Greenland rocks proved that water was already plentiful on earth some 3.8 billion years ago. Some workers have suggested that these ancient rocks already contain evidence for the presence of primitive life at this time, but I think that the evidence is still inadequate.
Q: Other findings that have come out of your work?
A: Numerous workers in many laboratories have studied these ancient Greenland rocks since 1971. Their work has helped to give a detailed picture of what the earth was like in its early stages; they’ve now compared and contrasted this with today’s terrestrial environment and found surprising similarities but also many important differences.
Q: Such as Greenland itself?
A: It looks exactly as it did in 1957. However, detailed measurements by meteorologists and glaciologists show that global warming is beginning to cause an increased rate of melting of the Greenland ice cap.
Q: Stephen, in the American Museum of Natural History in New York city, there is a boulder-sized display of a banded iron formation. It is said to occur almost exclusively in very ancient rocks. Is this similar to what you and your colleagues uncovered in Greenland?
A: Banded iron-formation (we call it BIF) is a major component of the oldest (3.8 billion years) rocks in the Isua region of West Greenland. It is a sedimentary rock deposited under water, composed of magnetite (iron oxide) and quartz (silicon oxide). I think that the BIF boulder in New York’s museum comes from Isua—and I think I helped to collect it!
Q: What a thrill that must have been!
A: The excitement and expectation of finding something often exceeds the thrill of what you actually find.
Q: What about stromatolites? I love the way they look. Any of those in Greenland?
A: We have yet to find any stromatolites there. But such creatures still survive today. The best known ancient stromatolites come from Australia and South Africa. They’re widely recognized as demonstrating the existence of primitive life on earth by somewhere around 3.5 billion years ago.
Vicki Leon: Fascinating to learn this, Stephen. We’ve got lots more to quiz Stephen Moorbath about, so please join us on my next blogpost for Part 2 of “A Fresh Eye.”