Inaccurate radiometric dating, i. methods of dating ice cores
The various dating techniques available to archaeologists
For example, the successive formation of post-Pleistocene shorelines at Cape Krusenstern Alaska provided J Louis Giddings with a means of ordering sites chronologically. The fact that not all of the argon is retained would account for smaller amounts of argon near the surface, as I will explain below.
This would probably have a larger effect lower down, where the pressure of argon would be higher.
Henke further states in his reply to me, Dickinp. Starting with the Bible produces different conclusions than starting with evolutionary reasoning. Evidence for the period of accelerated decay is found in zircon crystals. Other studies have shown multiple layers forming as the result of light rainfall, increasing river flow, and Inaccurate radiometric dating snowmelt.
Visual Layers Summer ice has more bubbles and larger crystal sizes Observed to 60, years ago Dust Layers Measured by laser light scattering; most dust is deposited during spring and summer Observed toyears ago Layering of Elec-trical Conductivity Nitric acid from the stratosphere is deposited in the springtime, and causes a yearly layer in electrical conductivity measurement Observed through 60, years ago Contaminant Chemistry Layers Soot from summer forest fires, chemistry of dust, occasional volcanic ash Observed through 2, years; some older eruptions noted Hydrogen and Oxygen Isotope Layering Indicates temperature of precipitation.
So if a rock has tiny cracks permitting gas to enter or escape or permitting the flow of water, the radiometric ages could be changed substantially even without the rock ever melting or mixing. Although there might be some mineral differences due to the difference in source rock, most sedimentary rock deposited year after year look very similar to one another.
But this would require an atom by atom analysis, which I do not believe is practical.
The reason this age may not be a true age—even though it is commonly called an absolute age—is that it is based on several crucial assumptions.
It is possible that in some cases an isochron might be able to detect such initial argon 40, but this can only happen if the potassium concentration varies significantly within the sample. Hyde has posted separately some of the relationships between ocean core data and their astronomical causes.
If they contained a hundred times more excess argon, their K-Ar ages would be a hundred times greater, I suppose.
The major disadvantage of this dating method is that these isotopes also tend to diffuse over time. In a similar way, argon could enter the rock from the air or from surrounding rocks and make it look older.
There are at least a couple of mechanisms to account for this. Thus it is easy to rationalize any date that is obtained. In general, the dates that are obtained by radiometric methods are in the hundreds of millions of years range.
Argon from the environment may be trapped in magma by pressure and rapid cooling to give very high erroneous age results. Now, several factors need to be considered when evaluating how often methods give expected ages on the geologic column.
Many dating methods seem to give about the same ages on meteorites. Dendrochronology will probably eventually find reliable tree records that bridge this time period, but in the meantime, the carbon ages have been calibrated farther back in time by other means.
To make the case even stronger, "Many discrepant results from intrusives are rationalized away immediately by accepting the dates but reinterpreting the biostrategraphic bracket," according to John Woodmorappe. These amino acids start to spontaneously convert from their levorotary form to their dextrorotary form as soon as a creature dies in a process called "racemization".
Now, argon is very soluble in magma, which can hold a lot of it: Radiometric Dating Using ratios of isotopes produced in radioactive decay to calculate an age of the specimen based on assumed rates of decay and other assumptions.
The same goes for the dating of rocks using radioisotopes. In fact, the Greenland ice cap would not regrow under modern last 10 ky climatic conditions. Dating a peruvian man and paleontologists are highly self-critical, and they have worried for decades about these issues.
It wouldn't require many internal cracks to allow a ten millionth part of argon to enter.
This method is supposed to eliminate the assumption that the initial concentration of the daughter element is zero.
It just means that there is enough accuracy in the measurements to compute t to one or two percentage points of accuracy, where t is the time required to obtain the observed ratio of daughter to parent, assuming no initial daughter product was present at the beginning, and no daughter or parent entered or left the system.
This could account for the observed distribution of potassium-argon dates, even if the great sedimantary layers were laid down very recently.
It has been claimed that this can be accomplished by preheating samples under vacuum or by leaching them briefly with hydroflouric acid, or both