Direct vs indirect dating archaeology
We’re a donor-funded ministry, and we rely on friends like you to help keep us going!can made by a direct study of an artifact or may be deduced by association with materials found in the context the item is drawn from or inferred by its point of discovery in the sequence relative to datable contexts.Reich and coworkers found that at cryogenic temperatures, lead becomes a superconductor, but the corrosion products formed from centuries of exposure to air and water (lead oxide and lead carbonate) do not superconduct.On the basis of magnetic measurements and comparison with artifacts that were known (using other techniques) to be up to 2500 years old, the group showed that the mass of lead corrosion products is directly proportional to an object's age (New Journal of Physics, 2003, 5, 99)* [ [Kinetics of amino acid racemization (epimerization) in the dentine of fossil and modern bear teeth Laureano Canoira, Maria-Jess Garca-Martnez, Juan F. Ortz, Trinidad De Torres International Journal of Chemical Kinetics 35(11):576-591 (2003)] [ARCHAEOLOGICAL APPLICATIONS OF AMINO ACID RACEMIZATION  quote: "The results provide a compelling case for applicability of amino acid racemization methods as a tool for evaluating changes in depositional dynamics, sedimentation rates, time-averaging, temporal resolution of the fossil record, and taphonomic overprints across sequence stratigraphic cycles."] * Relative methods Relative or indirect methods tend to use associations built from the archaeological body of knowledge. Ultimately, relative dating relies on tying into absolute dating with reference to the present.If this ash is found anywhere else in the world a date will already be known (bearing in mind transportation time).s investigating a site may wish to date the activity rather than artifacts on site by dating the individual contexts which represents events.Some degree of dating objects by their position in the sequence can be made with known datable elements of the archaeological record or other assumed datable contexts deduced by a regressive form of relative dating which in turn can fix events represented by contexts to some range in time.For example the date of formation of a context which is totally sealed between two datable layers will fall between the dates of the two layers sealing it.However the date of contexts often fall in a range of possibilities so using them to date others is not a straightforward process. Here we can see 12 contexts, each numbered with a unique context number and whose sequence is represented in the in "fig B".# A horizontal layer# Masonry wall remnant# Backfill of the wall construction trench (sometimes called construction cut)# A horizontal layer, probably the same as 1# Construction cut for wall 2# A clay floor abutting wall 2# Fill of shallow cut 8# Shallow pit cut# A horizontal layer# A horizontal layer, probably the same as 9# Natural sterile ground formed before human occupation of the site# Trample in the base of cut 5 formed by workmen's boots constructing the structure wall 2 and floor 6 is associated with.
These artifacts are referred to as "residual" or "residual finds".One example of this is which uses a process of tying floating chronologies of tree rings together by cross referencing a body of work.In practice several different dating techniques must be applied in some circumstances, thus dating evidence for much of an archaeological sequence recorded during excavation requires matching information from known absolute or some associated steps, with a careful study of stratigraphic relationships.If we know the date of context 1 and context 9 we can deduce that context 7, the backfilling of pit 8, occurred sometime after the date for 9 but before the date for 1, and if we recover an of artifacts from context 7 that occur nowhere else in the sequence, we have isolated them with a reasonable degree of certainty to a discrete range of time.In this instance we can now use the date we have for finds in context 7 to date other sites and sequences.