Relative dating determining the sequence of geologic events
Using these key or index fossils as markers, geologists began to identify a particular layer of rock wherever it was exposed.Because fossils are believed to record the slow but progressive development of life, geologist use them to identify the relative age of rocks throughout the world.Relative dating is a dating method that used to determine determine the relative ages of geologic strata, artifacts, historical events, etc.This technique does not give specific ages to items.
In each period of earth's history different fauna and flora evolved with similar faunas being characteristic of similar beds.
The plane or junction, marked by the thick green line, between both sets of strata is the unconformity.
At Thornton Force the junction is marked by a basal conglomerate.
After the uplift of the land, the forces of erosion attacked the highlands and the eroded rock debris was transported and redeposited in the lowlands.
During the same interval of time in another part of the world, the land surface subsided and was covered by the seas.
Techniques of accurately dating rocks is crucial in establishing the time-gap that exists.