A Whole New World
Plate Tectonics Inched Slowly From Theory to Acceptance
Today, the theory is accepted as fact by children in grade school. Not too long ago, the best minds in the geologic world were locked in debate -- and dispute -- that reached epic proportions.
Global plate tectonics.
In many ways the evolution of the global plate tectonics theory, a landmark development of the 20th century, has been as infinitely slow and ponderous as the continental movements it describes.
It, too, required a breakup of a Pangaea-like "supercontinent" of prejudice. Factions drifted apart, back together and then apart again. Occasionally they shifted direction, only to rotate, stall or collide at some later point.
For a very long time, forward motion was so gradual as to be practically imperceptible.
But just as the impact of two continents may without warning reshape a long-benign landscape by earthquake and volcanism, so did the old, much-maligned theory of continental drift -- tempered by fires of new research published decades earlier -- undergo a diagenesis that allowed it to re-emerge as the new foundation for geologic inquiry.
Acceptance of the theory, at times, seemed an impossibility -- and controversy was a constant companion. Today's geologic gospel was yesterday's heresy.
But finally the old intuitive visions -- of Pangaea, Gondwanaland, Tethys and Laurasia -- found validity in new, technically verifiable concepts such as seafloor spreading, geomagnetic reversal and crustal subduction.
Almost any geologist who has had a degree for longer than 25 years has some awareness of how diehard the old prejudices against continental drift could be. This was especially true in the United States, where earth scientists had fewer occasions to observe the geological indicators that had long intrigued scientists in the Southern Hemisphere.
In a sense, the theory's roots reach back to humanity's earliest days, when people sought explanations for the rumblings and violent eruptions that came from deep in the earth. Civilization has journeyed through the millennia wondering how mountain peaks pushed their way into the sky, and what lay beneath the vast waters of the oceans.
Crude but intriguing suggestions of continental movement were raised in the 1700s, shortly after the birth of geology as a science, and theories were periodically put forth and subsequently rejected -- but with each stumble, the science advanced a step.
For 20th century scientists, new versions of old ideas were swirling about in the early 1900s -- mainly in Europe and South Africa, and later in Japan -- waiting for a spark to bring ignition.
Even when the sparks were struck the theory advanced at a snail's pace.
But once technology was in place that allowed the proof to be gathered, U.S. researchers jumped in with both feet. And once the evidence began to be disseminated, U.S. scientists were swept up in a great wave of conversion.
There are still a few who continue to hold to other explanations for the configuration of the earth's crust, but an overwhelming majority now accept plate tectonics -- the natural heir to continental drift theory -- as fact.
When interest in the rejuvenated theory of continental drift began to spill over from research centers into the mainstream in the early- to mid-1950s, some of the old opposition was revitalized as well.
In the late 1960s and early 1970s, some authors continued to argue against the ideas of continental drift and plate tectonics. One of the best known opponents of the theory, the late A.A. Meyerhoff, was AAPG's publications manager and managing editor of the BULLETIN from 1965 to 1974.
Once academia's research began to be published in earnest in the mid- to late-1960s, the petroleum industry started to show increasing interest in tectonics research. Dave White was group leader for Exxon Production Research Co.'s project on the new global tectonics in 1968.
White, now a consultant in Austin, Texas, said he believes EPRCO was the first oil company research group to get into plate tectonics. A young member of the team named Pete Temple, who had studied under Harry Hess at Princeton, initiated the project.
"He was really fascinated by the subject and was always looking for a way to get back into it," White said. "So one day he and another member of the group, Tom Nelson, started looking at a seismic section from the Otway Basin off South Australia and they envisioned that what they were seeing was a pull-apart feature, where Antarctica had pulled away from Australia.
"Applying the theory, they then postulated that there should be a transform fault within a certain area near Tasmania at a right angle from the pull-apart," White continued.
"Sure enough, the fault turned out to be right where they thought it would be. I remember Pete coming into my office waving that seismic section in the air. He thought that was pretty neat, and I did, too."
White said so far as he knows that was industry's first practical application of global tectonic theory, in terms of making a prediction of a structural feature.
In the years since, the theory has reshaped geological thinking, from explaining how mountain ranges are built to the search for petroleum and other minerals.
"It has really pervaded exploration thinking, especially in large companies," White said. "A lot of exploration is unraveling the geological history, and the way to do that is to show where a continent was during the period of interest, what the depositional environment and climatic conditions were like. It helps you put some of the pieces of the puzzle together that you wouldn't have otherwise.
"It's a very broad sort of thing in its influence, difficult to quantify in terms of saying a particular discovery was made by applying global tectonics theory. But I can say I've seen some pretty great swatches of acreage picked up after a determination that the area was representative of a certain type of tectonic feature."
White counts himself fortunate to have been among those advocates of the theory who were privileged to have had a part in the research that finally vindicated it.
"I remember those years as the most exciting time I've ever had in geology or research," he said. "It was a period of great innovation, and there was a sense of being on the cutting edge of the science -- of experiencing history in the making."
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