Radiometric Dating
explained

Overview of Radiometric Dating:
There is no instrument available to measure the age of any substance. We can examine a rock, measure its composition and ratio of various elements, but we can never get a direct age. We must make assumptions based upon the chemical and mineral composition of a specimen before we can draw a conclusion about its age. These assumptions are often not accurate, therefore any “number” for an age of the specimen that you get is entirely based upon the accuracy of the assumptions, not the accuracy of the instrument measuring the chemical compositions. The most reliable means of dating an object is through historical evidence. Since evolution-believing scientists believe that the earth is much older than any historical record, they rely upon mineral compositions, and radioactive measurements to attempt to date an object.

Uranium-Lead Dating:
This dating method is used primarily on igneous rocks and is used to date objects thought to be quite old. Uranium-238 has a half-life of about 4.5 billion years. This means that if we could watch a sample of U-238 for 4.5 billion years, we would note that half of it would be gone, having decayed to Lead [Pb]-206.
U-Pb dating is based upon three assumptions:
1) A constant decay rate--this is a reasonable assumption based upon observed physical properties.
2) No loss or gain of Uranium or Lead during the "life" of the rock.--To avoid this problem, paleontologists choose specimes that appear to have no erosion forces acting on it. This is difficult to objectively guarantee, but it is nonetheless a reasonable assumption.
3) It is assumed that NO Lead was in the specimen when it was formed. This assumption is illogical, and is actually the entire basis for U-Pb dating. Why wouldn't there be Lead in the specimen when it was formed? Why would there be Uranium and no Lead? How do we know that there was no Lead in the specimen when it was formed?

How it works:
U-Pb dating is calculated after an igneous rock is analyzed for its content of U-238 and Pb-206. Since it is assumed that no Lead was in the specimen when it came into existence, then any Pb-206 found would apparently be from decayed U-238. If there are found to be equal amounts of U-238 and Pb-206, then half of the U-238 has decayed, and the specimen would be 4.5 billion years old.
In reality:
Any ratio of U-238 and Pb-206 would be due to random mixing of elements that were created in the beginning. Since our world is approximately 6,000 years old [see Geochronometers], only a fraction of Pb-206 would be attributed to U-238 decay.
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K-Ar dating: [Potassium-Argon]
2.4% of the earth’s crust is K. 1/10,000 Potassium molecules is radioactive K-40. This decays to Argon-40 with a half life of 1.3 billion years. This method is used to date igneous and volcanic rocks. This is the supposed way it works: When a rock melts, all the Argon-40 gas escapes the lava and goes into the atmosphere. From that point on, K-40 decays and forms new Ar-40. Then the ratio of K-40 to Ar-40 can be measured and a conclusion drawn as to how long ago the rock was molten. K-Ar dating is used for dating supposedly OLD rocks.
Assumptions:
1) All Argon gas escapes from molten rocks
This has been proven wrong on many occasions. In 1986, lava from Mt. St Helens was immediately tested and was found to have Argon-40 gas in it as soon as the rock cooled. This gave a K-Ar date of 350,000 years for a rock that had just cooled! We now know that different types of mineral rocks occlude Argon gas within their mineral structures at a molten state.
2) All Argon-40 gas in a specimen comes only from K-40 decay.
This assumption is as illogical as saying that all Pb comes from Uranium decay. There is no logical reason to believe that our world would form with Uranium and K, but not Pb or Argon.
Interesting caveat: Old-earth Paleontologists are careful not to date rocks which are in higher geologic strata than strata that contains human remains. So again we see that old-earth scientists continually rest their final conclusions upon what they consider to be a “known” dating system…the geologic column. We choose to use a known dating system…the Bible.

How it works:
A volcanic or dacite rock is analyzed and a ratio of K-40 and Ar-40 is measured. Since it is assumed that all Ar-40 in the world has come from K-40 decay, then if the ratio of K-40 to Ar-40 is 1:1, half of the previous K-40 must have decayed and the specimen is 1.5 billion years old.
In reality:
Nearly all Ar-40 that is found was present at creation, just as K-40 was present at creation. So the calculations are based upon a flawed and illogical [and at the very least unproven!] assumption!


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Radiocarbon Dating:
Normal Carbon has a molecular weight of 12. Radioactive Carbon has a molecular weight of 14. This C-14 is formed in our atmosphere when ionizing radiation hits Nitrogen-14 and converts it to C-14. The current ratio in our atmosphere of C-14 to C-12 is 1:1 trillion. C-14 naturally decays back to N-14 at a half-life of 5,730 years.
It is important to note that Radiocarbon dating is only used [even by the most avid C-14 dating proponents] to date recent specimens. No one would claim that Radiocarbon dating has anything to say about specimens greater than 10,000 years old!

How it works:
Plants [and by extension, animals and man] consume Carbon dioxide from the atmosphere, thus taking in a certain amount of C-14. This comsumption continues until the plant or animal dies. Then the C-14 continues to decay to N-14 and the organism no longer takes in any more C-14 because it is dead. A scientist can then measure the amount of C-14 in a specimen compared to the amount of C-12 in the specimen. Then this ratio is compared to the ratio of C-14/C-12 in the atmosphere and an age of the specimen [after its death] can supposedly be drawn.

Assumptions:
1) That atmospheric C-14/C-12 ratio is known in the past, or that it is stable. This is where C-14 dating fails miserably. This is why most scientists have considered this dating technique as un-useable. The fact is that the ratio of C-14 to C-12 is constantly climbing. If the atmosphere were millions to billions of years old, it should be in equilibrium already. It would take approximately 30,000 years for the ratio to stabilize. The fact that the ratio is still climbing is evidence that our atmosphere is less than 30,000 years old!--so as it turns out, C-14 dating actually supports a young earth beautifully!!

In reality:
C-14 dating is imprecise, even for recent dates. This is owing to the ever changing ratio of C-14 to C-12 in the atmosphere. Evolution-believing scientists have resorted to using tree ring C-14 analysis to determine the expected C-14/C-12 ratio in years past. Of course since no tree has been found that has tree rings going back even 100,000 years, this dating method still does not help date the earth, but only recent objects [with imprecision].
Note this quote found in an Anthropological Journal:
“The troubles of the radiocarbon dating method are undeniably deep and serious. Despite 35 years of technological refinement and better understanding, the underlying assumptions have been strongly challenged, and warnings are out that radiocarbon may soon find itself in a crisis situation. Continuing use of the method depends on a “fix it as we go” approach, allowing for contamination here, fractionation there, and calibration whenever possible. It should be no surprise, then, that fully half of the dates are rejected. The wonder is, surely, that the remaining half come to be accepted.
No matter how ‘useful’ it is, though, the radiocarbon method is still not capable of yielding accurate and reliable results. There are gross discrepancies, the chronology is uneven and relative, and the accepted dates are actually selected dates.”
[Lee, Robert. “Radiocarbon, Ages in Error,” Anthropological Journal of Canada, Vol. 19, No. 3, 1981, pp9,29.]