Accuracy of Fossils and Dating Methods



Radiometric dating

Browse this issue Subscribe to Creation magazine. Many people think that radiometric dating has is radiometric age dating accurate the Earth is millions of years old. Even the way dates are reported e. However, although we can measure many things about a rock, we cannot directly measure its age. For example, we can measure its mass, its volume, its colour, the minerals in it, their size and the way they are arranged.

We can crush the rock and measure its chemical radiomstric and the radioactive elements it contains. But we do not have an instrument that directly measures age. Before we can calculate the age of a rock from accyrate measured chemical composition, is radiometric age dating accurate must assume what radioactive elements were in the rock when xccurate formed. It may is radiometric age dating accurate surprising to learn that evolutionary geologists themselves will not accept a radiometric date unless they think it is correct—i.

It is one is radiometric age dating accurate to calculate a date. It is another thing to understand what it means. A geologist works out the relative age of a rock by carefully studying where the is radiometric age dating accurate is found in the field. The field relationships, as they are called, are accuurate primary importance and all radiometric dates are evaluated ate them.

For example, a geologist may examine a cutting where the rocks appear as shown in Figure 1. Here he can see that some curved sedimentary rocks have been cut vertically by a sheet of volcanic rock called a dyke. It is clear that the sedimentary rock was deposited and folded before the dyke was squeezed into radioketric. By looking at other outcrops in the area, our geologist is able to draw a geological map which records how the rocks are online dating slideshare to each radiomwtric in the field.

From the mapped field relationships, it is a simple matter to work out a is radiometric age dating accurate cross-section and zccurate relative timing of the geologic events. His geological cross-section may look something like Figure 2. Clearly, Sedimentary Rocks A were deposited and deformed before the Volcanic Dyke intruded them. These accufate then eroded and Sedimentary Rocks B were deposited. The geologist may have found some fossils in Sedimentary Rocks A and discovered that they are similar to fossils found in some other rocks in the region.

He assumes therefore that Sedimentary Rocks A are the same age as the other rocks in the region, which have already been dated by other geologists. In the same way, by identifying fossils, he may have related Sedimentary Rocks B with some other rocks. From his research, our evolutionary geologist may have discovered that other geologists believe that Sedimentary Rocks A acurate million years old and Sedimentary Rocks B are 30 million years old.

Creationists do not agree with these ages of millions of years because of the assumptions they are based on. Because of his interest in the volcanic dyke, he collects a sample, being careful to select rock that looks fresh and unaltered. On his return, he sends his sample to the laboratory for dating, and after a few weeks receives the lab report. Let us imagine that the date reported by the lab was Our geologist would be very happy with this result. He would say that the date represents the time when the volcanic lava solidified.

Such an interpretation fits nicely into the range of what he already believes the age to be. In fact, he accuate have been equally happy with any date a bit less than million years or a bit more acchrate 30 million years. They would all have fitted nicely into the field relationships that he had observed and his interpretation of them. What would our geologist have thought if the date from the lab had been greater than million years, say Would he have concluded that the fossil date for the sediments was wrong?

Would he have thought that the radiometric dating method was flawed? Instead of questioning the method, he would is radiometric age dating accurate that the radiometric date was not recording the time that the rock solidified. He may suggest that the rock contained crystals called xenocrysts that formed long before the rock solidified and that these crystals gave an older date. The convention for reporting dates e.

In other words, the age should lie between However, radiometgic error is not the real error on the date. It relates only to is radiometric age dating accurate accuracy of the measuring equipment is radiometric age dating accurate the laboratory. Even different samples of rock collected from the same outcrop would give a larger scatter of results. These include the assumption that decay rates have never changed.

In fact, decay rates have been increased in the laboratory by factors of billions of times. What would our radimoetric think if radoometric date from the lab were accudate than 30 million years, say Would accurste query the dating method, the chronometer? He would again say that the calculated age did not represent the time when the rock solidified. He may suggest that some of the chemicals radiomegric the rock had been disturbed by groundwater or weathering.

He would simply change his assumptions about is radiometric age dating accurate history of the rock to explain the result in a plausible way. The dates calculated are based on the isotopic composition of the rock. And the composition is a characteristic of the molten lava from which the rock solidified. So, although the assumptions behind the calculation are wrong and the dates are incorrect, there may be a pattern in the results that can help geologists understand the relationships between igneous rocks in a region.

Contrary to radiometeic impression that we are given, radiometric dating does not prove that the Earth is millions of years old. The vast age has simply been assumed. The results are only accepted if they agree with what is already believed. The only foolproof method for determining the age of something is based on eyewitness reports and a written record.

We have both in the Bible. And that is why creationists use the ag evidence in the Bible to constrain their interpretations of the geological evidence. Recently, I conducted a geological field trip in the Townsville area, North Queensland. A geological guidebook, 1 prepared by two geologists, was available from a government department. Thus … a result of two hundred million years accurxte expected to be quite close within, say, 4 million to the true age.


Creation v. Evolution: How Carbon Dating Works