Soil Dating Question *This is NOT a religious thing. The Earth is 4.567 billion years old. NO NUT-JOB ANSWERS*

Question

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?

Answer 1

You are right that geologists do pay attention to the relative order of rock layers to help determine relative ages. But, they also realize that erosion brings ancient layers to the surface. Dinosauar fossils are exposed at the surface in Utah,for instance. So, geologists don't use a simple model of depth to determine age of a rock when they are mapping. They use a knowledge of fossil history and also try to get absolute ages when they have rock types that can be dated that way.
You are correct that, in dating a surface layer, geologists need to make a distinction between the rock exposed near the surface and the very young soils that develop on the rock at the earth's surface--because dating soil won't give you the age of the rock. To get at the age of soil, or the age of an exposed surface, they might use analyses of soil horizons, pollen records, tree ring records, tephrochronology, luminescece, isotopic dating techniques involving carbon isotopes, cosmogenic isotopes, uranium isotopes, etc.

Answer 2

Your specific reference to the Pando does not necessarily contradict the geologic method of relative soil or rock layer dating (or the principle of original horizontality which assumes that all rock or soil layers were originally deposited horizontally and thus the layer on top is the youngest). Keep in mind that the Pando in Utah is a root system that expresses itself on the surface in the form of vegetation. The vegetation is periodically killed by fire, drought, etc. or buried by sediment over the years and then the roots push up new vegetation to the existing surface level. So, the Pando roots may in fact be 59.23 feet deep (depending on where this number comes from) or the deeper parts of the organism simply die off.

Answer 3

The Bible states this earth is eons and eons in age; in fact, 2 peter Chapter 3 in the manuscripts (and backed up by the Massorah) states that not only is the Earth billiions of years old, but that there was an entire earth age before this one that we live in now. I don't know about "forward minded", but I do know that this is the same Holy Scriptures that have been around forever - its just that people do not care enough to check out what they actually say, or too lazy to take it back to the original language, or else they are content to just believe whatever tripe some priest or pastor lays on them. There is no controversy between true Science and the Word of God, and no reason to feel that you need to jump onto one bandwagon or the other. I am a Christian devoted to Christ and I celebrate any time one of our Worlds dedicated Scientists realize a find; anything short would be immature and unnecessary.

Answer 4

Soil dating, by its very nature, HAS to be somewhat imprecise. If there was excessive volcanic activity in a certain year (or years) the soil layers might be deeper, or flood activity may have washed away soil layers, etc. You can really only get an estimate, but never something that will completely accurate. Your estimates might be very good, but an exact answer is most likely impossible.

Answer 5

Rock layers push on top of other layers. This is called plate techtonics.