Relative dating biostratigraphy
Generally, where in situ fossils are relatively abundant, reworked fossils are less common.
High-resolution methods are quantitative approaches that, in addition to species ranges, use subtle paleontological changes (e.g., fossil abundance and diversity peaks).
Figure 2 shows how variations in the relative proportion of individual species within assemblages can be used to characterize correlatable fossil “populations.” Ratios or percentages of in situ vs.
reworked calcareous nannofossil or palynomorph species may differentiate among distinct sediment packages.
A biostratigraphic zone is a body of rock defined or characterized by its fossil content.
The clustering of fossil extinctions often represents missing or condensed sections.
Although absolute ages are not necessarily critical for well correlations, they are vital in studies that rely on determinations of geologic rates.
In the field of Geology, dating is an important term as it is a technique through which evaluation regarding the age and period about the fossil, remains, the archaeologists do valuables and artifacts.
In the absence of index fossils (e.g., within areas of high clastic dilution or when extending a chronostratigraphic horizon across environmental boundaries), correlation methods other than the traditional use of fossil extinctions play an important role.Figure 3 shows how a comparison of the presence and abundance of different components of the assemblage (e.g., in situ vs.reworked faunas and floras) may enhance local correlations and help us identify sediment source.The inception (“*” in the illustration below), or lowest occurrence of a species or lineage, is a reliable datum only in core or outcrop samples because caving is virtually unavoidable in cutting samples; however, it can help refine the stratigraphy.The overlap of species extinctions and inceptions allows the development of range zones (see figure below), which can be correlated from site to site.