Compare and contrast relative dating and radioactive dating america dating site for
his document discusses the way radiometric dating and stratigraphic principles are used to establish the conventional geological time scale.It is not about the theory behind radiometric dating methods, it is about their , and it therefore assumes the reader has some familiarity with the technique already (refer to "Other Sources" for more information).There are situations where it potentially fails -- for example, in cave deposits.In this situation, the cave contents are younger than both the bedrock below the cave and the suspended roof above.For example, the principle of superposition is based, fundamentally, on gravity.In order for a layer of material to be deposited, something has to be beneath it to support it.This document is partly based on a prior posting composed in reply to Ted Holden.My thanks to both him and other critics for motivating me.
In such a situation, the "principle of superposition" is easily applied, and the strata towards the bottom are older, those towards the top are younger.As an example of how they are used, radiometric dates from geologically simple, fossiliferous Cretaceous rocks in western North America are compared to the geological time scale.To get to that point, there is also a historical discussion and description of non-radiometric dating methods.Despite this, the "principle of cross cutting relationships" can be used to determine the sequence of deposition, folds, and faults based on their intersections -- if folds and faults deform or cut across the sedimentary layers and surfaces, then they obviously came after deposition of the sediments.You can't deform a structure (e.g., bedding) that is not there yet!
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They are applied by geologists in the same sense that a "null hypothesis" is in statistics -- not necessarily correct, just testable.