The founder and the great champion of uniformitarianism
[ad_1]
Through Robert Hazen, Ph.D., George Mason University
James Hutton was a Scottish geologist who believed that a great geological change could have occurred over countless decades of gradual increases called “uniformitarianism”. This idea contrasts sharply with “catastrophism,†a competing doctrine, which held that most of the features of Earth arose as a result of violent events, in particular a dramatic flood.
James hutton
James Hutton, the founder and great champion of uniformitarianism, lived from 1726 to 1797.
By his early forties he had retired to study geology, particularly in the Edinburgh area. He particularly appreciated the rich intellectual life around this city in the 1780s and 1790s.
At that time, the prevailing wisdom was that the Earth was about 6,000 years old; that’s all. This is in accordance with the literal interpretation of biblical chronology; in particular the chronology proposed by Bishop James Usher, who lived from 1581 to 1656.
In such a climate of religious thought, very few thought of the implications of millions, or hundreds of millions, or even billions of years of change; but Hutton was different.
This is a transcript of the video series The joy of science. Watch it now, on Wondrium.
Noachian flood and geological doctrines
At the time, most geological features were interpreted as the result of the one great catastrophic flood, which was the Noachian Flood, and this belief supported two dominant geological doctrines of the 18e century.
The first was catastrophism, that is, geological change occurs through catastrophes. The second was called “neptunism”, and it is the idea that rocks are formed mainly under the action of water, either in the form of sedimentary layers of particles deposited on top of each other, or often by precipitation. chemical. Many people thought that basalts and limestones were just chemical deposits precipitated out of water.
However, Hutton differed. He realized that the most spectacular changes in the surface of the Earth are told by the testimony of rocks, outcrops, cliffs. He traveled from outcrop to outcrop around his native Scotland, and he learned the dramatic story the rocks were to tell.
Learn more about the rock cycle.
A great find by Hutton
One of the greatest discoveries was Hutton’s interpretation of a remarkable cliff near the town of Jedburgh in Scotland; it is about 35 miles east of edinburgh. At this rocky outcrop there are layers of intensely folded rock at the bottom of the hill; very, very intensely bent, but they are cut. Above these rocks are layered sediments, containing evidence of sedimentation and also containing fossils.
In these rocks, Hutton saw a succession of periods of sedimentation: burial, compression, folding, then uplift and erosion, each of which lasted millions of years.
First, he said there must be a shallow ocean or sea, and the sediment settled down layer by layer in a flat way. Then these layers had to be buried. They had to be heated, compressed and turned into rock layers. Then great forces, tectonic forces, came in and pressed them so that these flat layers bent intensely; and it must have happened deep underground.
After that, there must have been a period when all these rocks were lifted above sea level because you could see the feature of erosion. Then they had to be buried again, under another sea or another ocean. Then there had to be more layers of sediment deposited; they had to be buried deep enough for these layers to turn into rock.
Eventually the whole thing had to be lifted again, cut by a river or stream, and the cliff could be seen.
Volcanism: essential agent of change
In all of these processes, Hutton also viewed the Earth’s internal heat as a key change agent; and this point of view is called “volcanism”, in stark contrast to neptunism. Here is Hutton saying that instead of catastrophic events and water being the primary agent of change, you must also seek immense stretches of time, and heat being an agent of change.
Over and over, he said, these processes have happened, and the cycles take tens or hundreds of millions of years, maybe even longer. He saw no way to tell how long the vast expanses of geological time were; but certainly, being limited to 6,000 years was absurd, in his eyes.
“The theory of the earth”
Hutton’s ideas were published in a groundbreaking but largely illegible text called The theory of the earth. In Hutton’s own words, he said: “The result, therefore, of our present investigation is that we find no vestige of a beginning, no prospect of an end. Unfortunately, the way Hutton wrote was so indecipherable in the text of his work that most people ignored it.
But Hutton’s great friend John Playfair, also a resident of Edinburgh, contributed to the acceptance of uniformitarianism through his highly persuasive popular narrative, Illustrations of the Huttonian theory of the Earth, which was published in 1802.
Learn more about Earth as a planet.
Consequences of cumulative change
There are many examples of the dramatic consequences of slow, cumulative change, and you can see them all over the world.
In many places, including the highest mountains of the Rockies, the Alps, the Himalayas, you find fossils of marine creatures at the highest point. At the top of the rocks of Mount Everest are limestones that were once deposited in an ocean; and have somehow, over geological time, been elevated to the highest point on Earth.
Earth is a dynamic, constantly changing planet. All of these geological processes, acting over millions of years, lead to dramatic changes and weathering of the Earth’s surfaces.
Common questions about James Hutton and uniformitarianism
James hutton was a geologist who lived in Scotland between 1726 and 1797. He was the founder and great champion of uniformitarianism. He believed that the geological changes had occurred gradually over billions of years.
One of James huttonThe greatest finds were the remarkable interpretation of the rock near Jedburgh, Scotland. What Hutton observed on these rocks were successive periods of sedimentation; each having taken millions of years to form.
Hutton’s ideas were published in a groundbreaking but largely illegible text called The theory of the earth. The way Hutton wrote was so indecipherable that most people ignored it. But Hutton’s great friend John Playfair contributed to the acceptance of uniformitarianism through his highly persuasive popular narrative, Illustrations of the Huttonian theory of the Earth, which was published in 1802.
Keep reading
Fossils: life cast in ancient stone
Coal: a lesson in economic geology
Fascinating features of the Earth’s core
[ad_2]