A Time of Revolution

Image: Jason Morgan

Jason Morgan set earth science on a new course with his contributions to plate tectonics theory.

By Erika Archibald
Photography by Laura Sikes

I t was one of those rare times in the history of science-a time of excitement, of new data and new discoveries coming forth almost daily. And, finally, it was a time of breakthrough. It was, in fact, a time of revolution, one of the few true scientific revolutions of this century. The time was the 1960s, and the discoveries were those that would soon lead to our understanding of how the surface of the Earth works, how the continents and oceans were formed, how mountains and volcanoes evolve, why and where earthquakes happen.

The revolution brought forth the now widely accepted, overarching theory called "plate tectonics," which suggests that the upper level of the earth is divided into a number of rigid pieces, or plates. The concept has, in. turn, revolutionized the earth sciences in this century.

At the fore- front of it all, thinking faster and better than almost any other scientist out there, was a young Georgia Tech physics gradu- ate, W. Jason Morgan.

A Plate Tectonics Primer

Image: Earth Cross-section

Image: Crust Cross-section P late tectonics is the widely accepted, all-encompassing theory that suggests the upper level of the earth--the lithosphere-- consists of a number of somewhat rigid pieces, or plates.

These plates move about relative to one another on an underlying viscous layer called the asthenosphere. The interactions of the plates at their boundaries accounts for the formation of most of the earth's geographical features, such as mountains and oceans.

Near the beginning of this century, German scientist Alfred Wegener championed the idea that one supercontinent--Pangaea-- had broken up into the separate continents we know today, but these ideas lost their champion when Wegener was killed while on an expedition. Wegener had derived his ideas from studying the geography of the Atlantic coastline and the continuity of certain geological features across continents.

During the 1950s, paleomagnetic studies and new data from the ocean floors began to re-establish the idea of continental drift, and that of seafloor spreading. In the late 1960s, W. Jason Morgan and a few other scientists published ideas that, within a few years, were developed into the ideas of plate movement and boundary interactions-plate tectonics.

Nowadays, plate tectonics is to earth sciences what the understanding of atoms and molecules is to chemistry. It is the basic process by which geological activity, like earthquakes and volcanoes, is understood. In explaining how the earth's surface works, through plate tectonics, geologists can now also offer practical information on where earthquakes will occur and how large they will be, or where mineral resources are most likely to be found. Plate tectonics also suggests what will happen to various parts of continents-like the Atlantic Ocean plunging beneath the United States-but the questions of when are still way beyond what is known.

In addition, plate tectonics has significant implications for the study of life on Earth since the various geographical features of earth have certainly influenced the development of species. However, plate movements do not seem to be limited to our planet. Research has suggested that Venus appears to have had plates, although they seem to have slowed down to a near stop right now. The moons of Jupiter have also been studied for plates.

Unexplained questions derived from these studies may lead to new understandings of what is happening on Earth, of why it is happening, and of where this is all leading.

Putting Together the Puzzle

A s is often the case at times of unfolding scientific sea changes, numerous scientists were working along related lines of thought, trying to analyze and interpret new data-in this case from the ocean floor- and the new theories that were being suggested to explain it.

While doing post-doctoral work in geophysics (the study of the earth using the tools of physics) at Princeton, Morgan became very interested in this new data from the ocean floor, much of it being provided by ships from the Navy. An office mate, scientist Fred Vine, who had already done significant work in explaining the story of the ocean floor through magnetic anomalies, encouraged Morgan to follow his new ideas about ocean formation and what was happening at the mid-ocean ridges and at the trenches, two areas now understood to be plate boundaries.

As it happens, other scientists were working on the same data, each coming up with various parts of what is now seen as a larger puzzle. The question of who was actually first in conceiving the idea of plate tectonics is, therefore, hard to answer, since several scientists were approaching the concept independently.

"I like to think of myself as the first," says Morgan, who recently received an honorary doctor of science degree from Harvard University. recognizing his crucial role in formulating the theory of plate tectonics. "Jason's contribution was seminal, of enormous importance," says Vine, whose own work laid a foundation for the work of Morgan and others. Vine, who is now dean and professor of environmental sciences at the University of East Anglia in Norwich, England, shared an office with Morgan at Princeton in the late 1960s when this work was in its heyday. "As far as I could see-as someone very close to what was going on-he independently formulated the concept of plate tectonics," Vine says, describing Morgan as "truly one of the fathers of the plate tectonics revolution."

What led Morgan to conceive of this all- encompassing concept of plate tectonics? Well, according to Morgan, most of his ideas come from pure theorizing. He began with the oceanographic data, theorizing about what was happening at mid-ocean ridges and at the trenches, two areas now understood to be plate boundaries. Within two years, he says, these ideas about the oceans were well accepted, but their implications for explaining the continents came a bit more slowly. After some presentations and articles on oceans, he turned toward the rest of the earth, gradually coming up with the idea of plates.

When asked to describe himself as a scientist, Morgan says he is very intuitive and theoretical, as opposed to being primarily a field scientist or a mathematician, for example-although he is certainly highly capable in those areas.

"One thing that differentiates him from almost all his peers is that he is always willing to question what almost everyone takes for granted," says Morgan's son, Jason P. Morgan, who has become a respected geophysicist in his own right and who has started working on some projects with his father.

"My dad, more than anyone I know, seems to be willing to take the approach of always wondering, 'How else could this be?' That may be linked to why he has some of the best insight and intuition into how things might work. He's continually questioning -- but not to the point were it might paralyze him -- what most people take for granted," even when the ideas are his own.

"If you ask about plate tectonics, almost everyone was thinking this means the plates are rigid blocks," Morgan Jr. explains. "But my dad was always wondering how rigid are these blocks? They might not be completely rigid. And, only 15 years later, there was a minor realization that this was true. So, even though he invented the idea of rigid plates, he didn't believe it like it was gospel."

A native of Savannah, Morgan started out his scientific career at Georgia Tech, where he majored in physics, graduating in 1957. He credits several Georgia Tech professors, including Vernon Crawford, who later became chancellor, and J.Q. Williams, with encouraging him to change his major from mechanical engineering to physics. After serving two years in the Navy, Morgan went on to graduate school at Princeton, obtaining his doctorate in 1964. He is now professor of geophysics at Princeton and holds the Knox Taylor Chair of Geography there as well. His work has also taken him to various research institutes and field sights around the world, from Iceland to Hawaii.

New Data, New Challenges

S ome 30 years since his first theories were formed, Morgan says work in the plate tectonics field is as exciting as ever because a whole new set of data is coming in-this time not from the oceans but from the skies, an outgrowth of space research and the use of satellites. Morgan explains that it is now possible to measure the location of any point on the Earth to within a centimeter, or even a millimeter, and that repeat measurements year after year show how one point moves toward or away from another point. This data is going to revolutionize tectonics, he says. Just as the magnetic ocean data in the 1960s showed how plates were pulling away and, thus, how oceans were evolving, the new data from space will show how fast a mountain range is going up or how much the Western states are pulling apart. Image: Crust movement

The tectonics revolution continues in other ways as well, say Morgan and his son. The duo has now teamed up to bring a new element into the study of geophysics- chemistry. Geophysics provides a general picture of the Earth's mantle (where the boundaries are), but the rocks from the mantle their chemistry-can provide really detailed data, if you know how to interpret them, Morgan says.

"The attempt is to use the chemistry of the rocks to test a model of the flow pattern of the mantle," he says.

Morgan's son, who earned a doctorate in geophysics from Brown University and is now a professor at the Scripps Institute of Oceanography, is the chief author of their joint effort to incorporate their geochemical data into a model of Earth convection. They expect to present this work to the academic community before the end of the year.

Morgan's son, working in the field some 30 years after the heady early days of the tectonics revolution, says that geophysics is really still a wideopen field. "We have a picture that there are revolutions in science, and then you sort of just fill in the cracks. But my view is that plate tectonics was a revolution describing a behavior of the system, but not understanding the dynamics of how the thing happens.

"In fact, I feel that geologists, for about 20 years, have had this untrue impression- and my dad feels the same way-that the problem is solved because we know how the surface is moving and because we know so much about what that means for mountains, volcanoes. Many people think the problem is solved because we can describe it. But, as a physicist, it isnt known until you know why it's happening."

Today, says Morgan Jr., with the explosion in new tools like the space data, the time is ripe for more of the revolution. Unfortunately, this false belief that all the big questions are solved means that it's hard to get funding for truly progressive-or aggressive-research, he says. "We're not encouraging risk at all. It's very natural, but it's extremely frustrating compared to the way it was in my dad's heyday." Image: Morgan and Crooks

Value in Teaching

I n addition to his continuing work in the field of tectonics, and the work of his son, Morgan continues to influence the field through his teaching at Princeton. Each year, he teaches a large freshman course on earthquakes and volcanoes, as well as a techniques course on geophysics. One of his favorite classes is a small freshman seminar in which he travels with the students to the Sierra Nevada mountains in California to do the laboratory portion of the class.

Several of his students have become active researchers in the field of plate tectonics and have worked on such problems as the nature of propigating rifts on the sea floor and the study of micro-plates along the midocean ridge. Teaching and research influence each other in another way too, says Morgan. "Sometimes students will ask questions you didn't ask, which makes you go back and study even more. You realize you do not know the answer to what they have asked, and you try very hard to get the answer before the next class."

So, whether the revolution is seen as over or not, the influence of one aggressively thoughtful Georgia Tech grad on how we understand our Earth will certainly be ongoing-through new research, through his son, through his students and through the general idea- building process of science, in which one intriguing idea begets another.

So, whether the revolution is seen as over or not, the influence of one aggressively thoughtful Georgia Tech grad on how we understand our Earth will certainly be ongoing-through new research, through his son, through his students and through the general idea- building process of science, in which one intriguing idea begets another. Erika Archibald, Ph.D., is an assistant professor of journalism and English at North Georgia College and State University. She formerly served as an editor for Atlanta Magazine and as public relations director for Zoo Atlanta.