In Search of the Polar Dinosaur
The idea that continents have not always been fixed in their present positions was suspected as early as 1596. At that time, Dutch mapmaker Abraham Ortelius noticed and described the close geometrical fit of different continents. A century later the same observation was made by the English natural philosopher Francis Bacon. Their voices were not heeded at the time. It was only in 1912 that the idea was introduced as a full-blown scientific theory--called continental drift--by a young German geophysicist named Alfred Lothar Wegener. He contended that around 200 million years ago a single supercontinent, Pangaea, began to split apart into the smaller continents that exist today.
Wegener's theory was largely dismissed by the scientific community as being preposterous. But the controversy he spawned raged on. By the mid-1960s the flow of scientific evidence became overwhelming. In particular, oceanographic research showed that the earth's surface, including the ocean floor, consists of relatively thin plates. These plates, separated by ridges, are continually shifting. Plate tectonics united the earth sciences from paleontology to seismology. Considered absurd just 40 years ago, the theory provided explanations for questions that scientists had speculated about for centuries--such as why earthquakes and volcanic eruptions occur in specific areas, and how mountain ranges like the Alps and Himalayas formed.
In 1991 the Cryolophosaurus ellito, a previously unknown dinosaur species, was discovered on the continent of Antarctica, only 400 miles from the South Pole. Studies showed that the Cryolophosaurus lived about 200 million years ago, when Antarctica was still part of Pangaea's subcontinent, Gondwanaland, and had a climate mild enough to support large plant-eating animals. With the breakup of Gondwanaland, Antarctica drifted southward to the pole.
By the time of this ultimate triumph of the continental drift concept, Alfred Wegener was long dead. He had frozen to death in 1930 crossing an ice cap in the Arctic, doggedly pursuing evidence to defend his rejected theory.
Wegener's theory was largely dismissed by the scientific community as being preposterous. But the controversy he spawned raged on. By the mid-1960s the flow of scientific evidence became overwhelming. In particular, oceanographic research showed that the earth's surface, including the ocean floor, consists of relatively thin plates. These plates, separated by ridges, are continually shifting. Plate tectonics united the earth sciences from paleontology to seismology. Considered absurd just 40 years ago, the theory provided explanations for questions that scientists had speculated about for centuries--such as why earthquakes and volcanic eruptions occur in specific areas, and how mountain ranges like the Alps and Himalayas formed.
In 1991 the Cryolophosaurus ellito, a previously unknown dinosaur species, was discovered on the continent of Antarctica, only 400 miles from the South Pole. Studies showed that the Cryolophosaurus lived about 200 million years ago, when Antarctica was still part of Pangaea's subcontinent, Gondwanaland, and had a climate mild enough to support large plant-eating animals. With the breakup of Gondwanaland, Antarctica drifted southward to the pole.
By the time of this ultimate triumph of the continental drift concept, Alfred Wegener was long dead. He had frozen to death in 1930 crossing an ice cap in the Arctic, doggedly pursuing evidence to defend his rejected theory.
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