They dated organic matter in lake varves, which today are seen to form annually. By counting the layers and checking them with the C14 results of stuff found in them they can see if the results correlate or not.
If C14 or the layers were unreliable, then there is no reason why these independent methods should correlate as nicely as they do.
In case of the other graph it's a correlation of suigetsu varve dates and coral layer dates which are shown, incorporating a full four independent dating methods (river varves, coral layers, C14 and uranium dating). If these don't work, why do they correlate?
Good Morning Bro.
O.K., first thing I noticed with the correlation between the varves is there are
many points where the C14 dated layers are off by 200 to 600 years (and
that's of the dates that were accepted as valid by the researchers).
Second, varve analysis is a rough guess at best:
Traditionally, when one "counted" varves, it proved to be a fairly monotonous and tiresome task resulting in much time lost and much subjectivity due to determining layers. One had to take microscopic evaluations of the material and form some sort of hypothesis or interpretation from the shape and thickness of the layers. This provided inaccurate data because different varve types can cause mistakes in the algorithm that is used and produce miscounts. For example, sub-annual laminations can be counted as extra years, and certain years may not deposit a carbonate layer, which often would not be counted. Thus, this technique is much criticized for providing insufficient data to determine such changes.
http://www.mnsu.edu/emuseum/archaeology ... varve.html
Varves have been used to set up the first "absolute" chronology, which significantly exceeds the Scriptural time scale from Genesis. Observations of modern glaciers and recent climate simulations show that the ice sheets during the Ice Age melted rapidly, much faster than indicated by varves. A further investigation of varves demonstrates that other mechanisms deposit varve-like couplets in a short time. Therefore, "varves" are not necessarily annual. A method to distinguish between annual depositional sequences and other mechanisms is difficult to apply. (Oard, p. 72)
Fischer and Roberts (1991) state, "In some cases the observer counting varves is left in doubt as to which couplets are varves and which are subvarve units, a matter that was handled in our image analysis varve counts by arbitrarily counting only variations above the 30 micron level." In other words, they arbitrarily chose 30 microns as the minimum thickness to be used for computer analysis. However, many laminations are less than 30 microns thick. Also, many of the "varves" consist of organic layers squeezed together with very tiny carbonate laminae in between. There is no consistency in varve structure.
Uranium-Thorium dating is subject to the same assumptions as C14
dating...uniformitarian interpretation of the decay rates.
Another particularly troublesome aspect of the technique is the requirement
for the object to be dated- it must take up uranium-238 and no thorium,
then immediately be closed off so it would not be able to take in more.
To me, that's very unrealistic.
The assumptions that each of these radiometric dating methods make are:
1. Each system has to be a closed system; that is, nothing can contaminate
any of the parents or the daughter products while they are going through
their decay processâ€â€or the dating will be thrown off. As we've discussed in
previous posts, there's no such thing as a closed system...except the
universe itself.
2. Each system must initially have contained none of its daughter products.
But how do you confirm this?
3. The process rate must always have been the same. The decay rate must
never have changed. I think this is extremely unrealistic, which is why i only
use C14 as a relative dating tool...not absolute. The decay rate of any
radioactive mineral can be altered [1] if the mineral is bombarded by high
energy particles from space (such as neutrinos, cosmic rays, etc.); [2] if
there is, for a time, a nearby radioactive mineral emitting radiation; [3] if
physical pressure is brought to bear upon the radioactive mineral; or [4] if
certain chemicals are brought in contact with it.
4. If any change occurred in past ages in the blanket of atmosphere
surrounding our planet, this would greatly affect the clocks in radioactive
minerals.
5. The Van Allen radiation belt encircles the globe. It is about 450 miles
above us and is intensely radioactive. According to Van Allen, high-altitude
tests revealed that it emits 3000-4000 times as much radiation as the
cosmic rays that continually bombard the earth.
Any change in the Van Allen belt would powerfully affect the transformation
time of radioactive minerals.
6. A basic assumption of all radioactive dating methods is that the clock had
to start at the beginning; that is, no daughter products were present, only
those elements at the top of the radioactive chain were in existence.
7. This factor of initial apparent age would strongly affect our present
reading of the radioactive clocks in uranium, thorium, etc.
If these don't work, why do they correlate?
So in summary, you can have different radiometric dates correlating for
a particular sample or between samples, but their still giving you relative
results, not absolute.
To make all the assumptions given above for the dating to be correct is
not reasonable in my opinion.
Peace
