However, radioisotope dating may not work so well in the future.
Between the years of 17, James Hutton and William Smith advanced the concept of relative dating.
Hutton, a Scottish geologist, first proposed formally the fundamental principle used to classify rocks according to their relative ages.
..radiometric methods of dating rocks, the ages of rocks and other geologic features could not be expressed quantitatively, or as numbers of years, but instead were expressed solely in terms of relative ages, in which the age of a particular geologic feature could be expressed as relatively younger or older than other geologic features. Local relationships on a single outcrop or archaeological site can often be interpreted to deduce the sequence in which the materials were assembled.
This then can be used to deduce the sequence of events and processes that took place or the history of that brief period of time as recorded in the rocks or soil.
The Virtual Courseware Project produces interactive, online simulations for the life science laboratory or for earth science field studies.
The activities are designed to enhance an existing curriculum and include online assessments.
He concluded, after studying rocks at many outcrops, that each layer represented a specific interval of geologic time.
Further, he proposed that wherever un-contorted layers were exposed, the bottom layer was deposited first and was, therefore, the oldest layer exposed; each succeeding layer, up to the topmost one, was progressively younger.
Seriation uses the assumption that once a tool was developed, its use would become more widespread.
Stratigraphy uses the assumption that higher layers or strata were laid down after lower layers.