what evidence did alfred wegener use to support his theory of continental drift
Continental Drift: The groundbreaking theory of moving continents
Continental drift was a revolutionary theory explaining that continents shift position on Earth's surface. The theory was proposed by geophysicist and meteorologist Alfred Wegener in 1912, only was rejected by mainstream science at the time. Scientists confirmed some of Wegener's ideas decades later, which are at present part of the widely accustomed theory of plate tectonics.
Wegener's continental drift theory introduced the idea of moving continents to geoscience. He proposed that Earth must have once been a single supercontinent before breaking up to form several unlike continents. This explained how similar rock formations and institute and creature fossils could be on separated continents. Modern science recognizes this ancient supercontinent chosen Pangaea did exist before breaking up nigh 200 meg years agone, as Wegener theorized.
Related: Massive supercontinent will form hundreds of millions of years from now
Why did scientists reject Wegener'south continental drift theory?
Geologists roundly denounced Wegener's continental drift theory later he published the details in a 1915 volume called "The Origin of Continents and Oceans." Part of the opposition was because Wegener didn't have a good model to explicate how the continents moved, something scientists later explained nether the umbrella of plate tectonics — the theory that Earth's chaff is fractured into plates that move over a rocky inner layer called the mantle.
"There's an irony that the central objection to continent drift was that in that location is no mechanism, and plate tectonics was accepted without a mechanism," to move the continents, Henry Frankel (1944–2019), an emeritus professor at the Academy of Missouri-Kansas City and author of the iv volume "The Continental Drift Controversy" (Cambridge University Press, 2012) previously told Live Science.
Though almost of Wegener'southward observations nigh fossils and rocks were right, he was outlandishly wrong on a couple of primal points. For instance, Wegener thought the continents might have plowed through the ocean crust like icebreakers smashing through ice.
Evolving theories
When Wegener proposed continental drift, many geologists were contractionists. They idea Earth'south incredible mountains were created because our planet had been cooling and shrinking since its formation, Frankel said. And to account for the identical fossils discovered on continents such as South America and Africa, scientists invoked ancient state bridges, now vanished below the sea.
Researchers argued over the land bridges correct upward until the plate tectonics theory was developed from the 1950s to the 1970s, Frankel said. For case, every bit geophysicists began to realize that continental rocks were too low-cal to sink downwards to the ocean floor, prominent paleontologists instead wrongly suggested that the similarities between fossils had been overestimated, Frankel said.
Plate tectonics is like a modern update to continental drift. In the 1960s, scientists discovered plate edges through magnetic surveys of the sea floor and through the seismic listening networks built to monitor nuclear testing, co-ordinate to Encyclopedia Britannica. Alternating patterns of magnetic anomalies on the sea floor indicated seafloor spreading, where new plate material is built-in. Magnetic minerals aligned in ancient rocks on continents also showed that the continents take shifted relative to one another.
Related: Plate tectonics are 3.six billion years old, oldest minerals on Earth reveal
What evidence is in that location for continental drift?
A map of the continents inspired Wegener's quest to explicate Earth'southward geologic history. He was intrigued by the interlocking fit of Africa's and South America'due south shorelines. Wegener then assembled an impressive corporeality of continental migrate testify to show that Earth'due south continents were once connected in a single supercontinent.
Wegener knew that fossil plants and animals such as mesosaurs, a freshwater reptile found only in Due south America and Africa during the Permian menstruation, could be institute on many continents. He also matched up rock formations on either side of the Atlantic Ocean like puzzle pieces. For example, the Appalachian Mountains (U.s.) and Caledonian Mountains (Scotland) fit together, as practice the Karoo strata in S Africa and Santa Catarina rocks in Brazil.
In fact, plates moving together created the highest mountains in the world, the Himalayans, and the mountains are yet growing due to the plates pushing together, even now, co-ordinate to National Geographic. Despite his incredible continental drift show, Wegener never lived to run into his theory proceeds wider credence. He died in 1930 at age 50 merely 2 days after his birthday while on a scientific expedition in Greenland, according to the University of Berkeley.
Additional resources
- Learn more than well-nigh the history of continental migrate and plate tectonics from the U.S. Geological Survey.
- Acquire more about Alfred Wegener from the NASA Earth Observatory.
- Scout this short video on YouTube about plate tectonics and continental drift, from National Geographic.
This article was updated on Dec. 14, 2021, by Live Scientific discipline Staff Writer Patrick Pester. Additional reporting past Alina Bradford, Live Scientific discipline contributor.
Source: https://www.livescience.com/37529-continental-drift.html
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