How does sedimentary layer dating reconcile itself with ancient objects which have managed to remain unburied (like the clonal colonies of trees in Utah that are at least 80,000 years old).
As I understand it, dating soil by layer is based on the idea that the topsoil is present day, then you go back in time as you dig down, with X feet equal to Y years.
So, might a geologist look at the clonal tree stand and say to a biologist: "Those things are on the surface, therefore they can't be 80,000 years old. If they were, they'd have (whips out a calculator) 59.23 feet of soil above them."
I may be oversimplifying, since I know some fixed lines, like the KT-Boundary exist at a specified position in known strata.
I guess the question I'm asking is: Is soil-layer dating absolute or relative?
To get a date based on depth do you, seemingly paradoxically, have to know the geological history (floods, erosion, past/present river courses) of the area already?
2007-02-07
20:45:44
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5 answers
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asked by
shankotron
1