Types of relative dating
This principle presumes that the oldest layer of a stratigraphic sequence will be on the bottom and the most recent, or youngest, will be on the top.The earliest-known hominids in East Africa are often found in very specific stratigraphic contexts that have implications for their relative dating.Stratigraphy is a branch of geology that studies rock strata with an emphasis on distribution, deposition, age and evidence of past life.Nicolas Steno, William Smith, Georges Cuvier, Alexandre Brongniart, and James Hutton developed the basic rules for the science of stratigraphy.The laws of physics and chemistry that governed geologic processes in the past are the same as those that govern processes now and in the future.The geologic timescale is a chronology (calendar) of events on Earth based on obtaining ages of past events.Cultural seriations are based on typologies, in which artifacts that are numerous across a wide variety of sites and over time, like pottery or stone tools.
Relative dating includes methods that rely on the analysis of comparative data or the context (eg, geological, regional, cultural) in which the object one wishes to date is found.
Unlike people, you can’t really guess the age of a rock from looking at it.
Yet, you’ve heard the news: Earth is 4.6 billion years old. That corn cob found in an ancient Native American fire pit is 1,000 years old. Geologic age dating—assigning an age to materials—is an entire discipline of its own.
Relative dating uses the principles or laws of stratigraphy to order sequences of rock strata.
Relative dating not only determines which layers are older or younger, but also gives insight into the paleoenvironments that formed the particular sequence of rock.
This also works with stone tools which are found abundantly at different sites and across long periods of time.