In geology, catastrophism is the belief that Earth's features—including mountains, valleys, and lakes—were created suddenly as a result of great catastrophes, such as floods or earthquakes. This is the opposite of uniformitarianism, the view held by many present-day scientists that Earth's features developed gradually over long periods of time.
Catastrophism developed in the seventeenth and eighteenth centuries when tradition and even the law forced scientists to use the Bible as a scientific document. Theologians (religious scholars) of the time believed Earth was only about 6,000 years old (current scientific research estimates Earth to be 4.5 billion years old). Based on this thinking and the supernatural events described in the book of Genesis in the Bible, geologists concluded that fossils of ocean-dwelling organisms were found on mountain tops because of Noah's flood. The receding flood waters also carved valleys, pooled in lakes, and deposited huge boulders far from their sources.
Over the next 200 years, as geologists developed more scientific explanations for natural history, catastrophism was abandoned. Since the late 1970s, however, another form of catastrophism has arisen with the idea that large objects from space periodically collide with Earth, destroying life. Scientists speculate that when these objects strike, they clog the atmosphere with sunlight-blocking dust and gases. One theory holds that the most famous of these collisions killed off the dinosaurs roughly 65 million years ago.
[ See also Uniformitarianism ]