EOSC 110 Chapter Notes - Chapter 8: Geologic Time Scale, Uniformitarianism, Actualism
Document Summary
The sedimentary rocks with marine fossils (clams, fish, etc) that we find in mountains thousands of metres above sesa level were believed to have been deposited by a worldwide flood (noah"s flood) that inundated all of earth. He realized that the great thicknesses of sedimentary rock we find on the continents are products of sediment removed from land and deposited as mud and sand in seas. The concept that geologic processes operating at present are the same processes that operated in the past eventually became known as the principle of uniformitarianism. Many geologists prefer actualism in place of uniformitarianism. Actualism comes close to conveying the principle that the same processes and natural laws that operated in the past are those we can actually observe or infer from observation as operating at present. Numerical age- age given in years or some other unit in time. Relative time- the sequence in which events took.
