When we look around our world today, we see a dynamic, almost chaotic planet that is constantly changing. Volcanoes erupt, the earth’s crust moves, mountains are weathered and other such activities occur around the world at almost any given moment. These dynamic events occur with such frequency and repetition that clearly defining a beginning or end is exceedingly difficult. Considering this difficulty and by relying on purely observational information, one can only assume that the processes that go on today have been going on since the earth was created. This precise idea is the very platform of the scientific view called uniformitarianism.
At the very dawning of the science of historical geology, James Hutton developed views on the earth’s geologic processes and ow they affect the planet unlike any other scientist before him. His idea that the planet’s processes revolved in a cyclic fashion were the cornerstone of uniformitarianism. Although he did not coin the phrase himself, an honor bestowed upon William Whewell, he did form the basic idea that the history of the earth can be explained by what is happening now.
Since this time, the term uniformitarianism has been manipulated, altered, and redefined to mean a variety of different meanings spanning various fields of science. However, in the field of geology, uniformitarianism (or actualism) means something very specific. The term does not denote that every process we see before us now has been going on for eons, rather it stand for the chemical and physical laws that govern today’s processes. Evidence shows that the ancient atmosphere of the earth is extremely different from the one we can see today. There fore, the means by which erosion and weathering of rocks that occurred then is a far cry from the ones we study in modern times. However, erosion and weathering still occurred, even if by different means. Most geologic processes are governed by a set of natural laws which uniformitarianism infers have always set the standard for geologic activity. If water freezes at zero degrees Celsius, what evidence is there to prove it has ever been different? Similarly, if rainwater falls on a mountain, erodes the rock, carries sediment to a stream, and then deposits sediments in the stream bed, what evidence proves nature has ever deviated from this? The rate of change and intensity of the processes have varied a great deal in the history of the earth and the fact is, there are some ancient processes that we do not see today. However, in the grand scheme of things, studying current geologic activity can give us a great deal of information about ancient environments and may even give us a clue as to our planet’s origins.
What is required for a planet to be able to support life? This is a question that people have been trying to answer for many years. Earth is a very unique planet because it is the only one proven to support life. Living organisms need certain things in order to survive that are not found on any other planet. Some of these life supporting features include food, water, atmosphere, temperature, ...
Just as historians and archeologists study artifacts and records of past human civilizations, so too does historical geologists study the records of past geologic activity. The archeologist may look at a broken piece of pottery and, using previous knowledge and evidence, come to the conclusion that the pottery was from a certain tribe or civilization that thrived during a specific time in history. Almost instantaneously, the archeologist can recreate and entire lifestyle using other artifacts gathered and similar information. The historical geologist’s job is quite similar, although the artifacts are typically much older. If, while out in the field one day, a geologist comes across a few layers of sandstone with alternating layers of conglomerates and fine grains, he instantly knows that this rock was formed from a stream bed that varied in water velocity at certain times during its formation. By studying the rock more closely, the geologist can determine what type of rock was weathered to form the sandstone and, using geologic maps, almost pinpoint the location of the parent rock. With just a little research, the geologist has recreated a basic history of the rock. The archeologist cannot determine that beyond a shadow of a doubt, the pottery was formed by human hands nor can the geologist be absolutely certain that the sandstone was formed the way he proposed.
Sedimentary rock formation begins with igneous, metamorphic, or other sedimentary rocks. When these rocks are exposed at the earth’s surface they begin the long slow but relentless process of becoming sedimentary rock. Weathering All rocks are subject to weathering. Weathering is anything that breaks the rocks into smaller pieces or sediments. This can happen by the forces of like wind, rain, and ...
However, using the idea of uniformitarianism, both scientists can state that because there is no evidence proving otherwise, this must have been formed in this way. The archeologist knows of no other being that could have made the pottery, so it is logical for him to assume that it was formed by human hands. On the same level, the geologist knows of no other processes that could form a rock such as the described sandstone and must assume that it was formed by a process he can readily see today: erosion and deposition. In this way, uniformitarianism helps us to form a history of the earth. A black rock with a very porous surface is evidence for volcanic activity and large deposits of sediment that resembles ground moraine of modern glaciers can be assumed to be ground moraine of previous glaciers.
The idea of uniform natural laws which govern processes is a very logical one. However, one must realize that no one can be absolutely certain that what we say happened actually happened. That is simply the chance we must take. We can only use our skills of observation and intellect and make educated guesses at what occurred. Uniformitarianism is almost exactly that. It is an educated guess using observational and purely objective evidence. This way, we can make our best attempt at putting together the vast and complicated history of earth.
Hamblin, W. Kenneth and Eric H. Christiansen. Earth’s Dynamic Systems. 7th Ed.
Prentice Hall. Englewood Cliffs, NJ. Copyright: 1995. Pg. 182-184
Levin, Harold L. Earth’s Dynamic Systems. 5th Ed. Saunders College Publishing
New York, NY. Copyright: 1996. Pg. 10-11