A comic depicting the implications of attributing mass extinction events to world wide flooding. Catastrophism was a theory developed by Georges Cuvier based on paleontological evidence in the Paris Basin. Cuvier was there when he observed something peculiar about the fossil record. Scientists look at modern-day geologic events—whether as sudden as an earthquake or as slow as the erosion of a river valley—to get a window into past events.
This is known as uniformitarianism : the idea that Earth has always changed in uniform ways and that the present is the key to the past. However, prior to , uniformitarianism was not the prevailing theory. Until that time, scientists subscribed to the idea of catastrophism. Catastrophism suggested the features seen on the surface of Earth, such as mountains, were formed by large, abrupt changes—or catastrophes.
When discussing past climates, opponents to uniformitarianism may speak of no-analog changes. This idea suggests that certain communities or conditions that existed in the past may not be found on Earth today. The idea of catastrophism was eventually challenged based on the observations and studies of two men—James Hutton and Charles Lyell. Hutton — was a Scottish farmer and naturalist. In his observations of the world around him, he became convinced natural processes, such as mountain building and erosion, occurred slowly over time through geologic forces that have been at work since Earth first formed.
He eventually turned his observations and ideas into what became known as the Principle of Uniformitarianism. Among the scientists who agreed with Hutton was Charles Lyell. Lyell — was a Scottish geologist. He found his own examples of these processes in his examination of rocks and sediments. For example, he discovered evidence that sea levels had risen and fallen in the past, that volcanoes may exist atop older rocks, and that valleys form slowly by the erosional power of water.
The combined efforts of Lyell and Hutton became the foundation of modern geology. After James Hutton's publication of "Theory of the Earth," increasing numbers of scientists came to understand that Earth processes usually are slow, gradual processes. The theory of uniformitarianism requires long periods of time and is summarized with the phrase "the present is the key to the past.
Studying modern geologic processes teaches geologists about past processes. In the mids the Scottish geologist Charles Lyell expanded the idea of uniformitarianism.
Lyell's "gradualism" extends the geologic principle to natural chemical and biological events, stating that changes occur gradually over long periods of time. Although catastrophism was largely set aside with the development of uniformitarianism and gradualism, many scientists have come to understand that catastrophic events influencing biology do occur. For example, the catastrophic meteor strike at the end of the Mesozoic, combined with the gradual separation of Pangea, led to the extinction of the dinosaurs, most marine reptiles and many other life forms.
Another example of a catastrophic geologic event affecting biology is the Japanese earthquake that drastically reduced the local population of mud snails and that spread local Japanese flora and fauna across the Pacific Ocean with the tsunami debris. Also, the eruption of large volcanoes like Tambora impact local ecosystems while influencing weather patterns world-wide. In the inorganic world, it is expedient to recognize two brands of catastrophism: the old and the new.
The old catastrophism was the ruling theory of Earth history before about It embodied many different ideas, but a common thread running through them was the recognition of one or more global, or nearly global, revolutions in Earth history, usually associated with world-wide floods and the collapse and crumpling of the Earth's crust.
As gradualism waned in the middle of the 19th century, so catastrophist views became rather disreputable Rudwick, During the present century, catastrophism has made a comeback Skip to main content Skip to table of contents. This service is more advanced with JavaScript available. Environmental Geology Edition.
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