The ten strata systems that compose the standard geologic column are the familiar Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, and Tertiary periods.
Although no absolute methods were available to establish actual dates, Lyell needed to assign very old dates to the strata to make them consistent with the long eons of time that would be necessary to meet the new uniformitarianism theory developed by James Hutton and himself.
If a certain kind of pollen is found in an archaeological site, scientists can check when the plant that produced that pollen lived to determine the relative age of the site.
Ice core sampling normally uses the assumption that the ring bands observed represents years.
One known example where this assumption was used is very misleading.
This method is based on the assumption (which nearly always holds true) that deeper layers of rock were deposited earlier in Earth's history, and thus are older than more shallow layers.
The successive layers of rock represent successive intervals of time.
Absolute dates must agree with dates from other relative methods in order to be valid.
The most widely used and accepted form of absolute dating is radioactive decay dating. Radioactive decay refers to the process in which a radioactive form of an element is converted into a nonradioactive product at a regular rate.
Dating techniques are procedures used by scientists to determine the age of an object or a series of events.
The two main types of dating methods are relative and absolute.
This theory held that the past was the key to the future and that processes that formed the layers were the very slow processes that we see forming layers at the bottom of the ocean today. Until Lyell successfully convinced scientists that uniformitarianism was the correct theory, it was believed that the worldwide flood and other catastrophic events were primarily responsible for the formation of the geologic layers and that they didnt represent long ages.
Later, when radiometric absolute dating methods were developed, they still were not applicable to sedimentary layers.
Before the advent of absolute dating methods in the twentieth century, nearly all dating was relative.