فارسی  |     
Home |  Contact Us |  Help 
Sciences - Geology > Stratigraphy
Walking along cliffs that were cut by ocean waves or rivers have always made humans wonder how they were formed. The time required to create such majestic towers has created serious debate, both scientific and religious.
Geologic time was very difficult for scientists to "discover." It was not until the mid 18th century that James Hutton, a Scottish geologist, realized that the Earth was many millions of years old. This was an unimaginable idea because people in his day believed the Earth was only a few thousand years old. Hutton tried to develop scientific methods to determine the time required for every day geologic processes and compare with the past. For example he tried to calculate mud accumulating in the ocean today, to figure out how much time had passed since the formation of the Earth. He used the term "uniformitarism" to compare the present day rock cycle with the past rock cycle. From these comparisons you can interpret how rock layers or strata were formed but not the length of time. You can determine which stratum is younger or older, just by the position of the strata. 
Since most rocks on the surface of the Earth are sedimentary, early geologists used them to look for answers to the age of the Earth. The birth of stratigraphy has its roots in scientists trying to determine the age of the Earth. They made simple predictions by looking at sedimentary processes going on today.