Radioactive dating method under fire
Log in Sign up. How can we help? What is your email? Upgrade to remove ads. The Pigs Took it All. The popular belief that radiometric dating stands in strong affirmation of the geologic time scale and the theory of human evolution. Many Christian accept this as evidence that the earth is very old merely because the methods appear impressive.
To look at what this popular belief is really about we need to look at two important geological finds in East Africa. Tuff strata and the well known fossil KNM-ER Inthe son of famed paleoanthropologists In English scientists who study ancient humans through fossil hominid evidence Louis and Mary Leakey, Richard Leakey visited fossil deposits in Northern Kenya.
He was trying to find hominid fossils. KNM-ER was the most important fossil the expedition found. Skull has a modern appearance but Richard Leaky estimated that it was 2. There was also a geologist named Kay Behrensmeyer that discovered a layer of volcanic ash, or tuff. The tuff was named after Kate Behrensmeyer Site Tuff KBS Tuff. If the tuff was found anywhere else it would have been overlooked but it was significant for three reasons.
While human fossils and artifacts can't usually be dated KBS Tuff can because it contains radioactive Potassium There were artifacts were found with the KBS Tuff. Hundreds of homo and australopithecine fossils have been found above and below the KBS turf. So the big question is why is this Tuff important? Well considering the tuff can be radiometrically dated it should give you a minimum estimate on the fossils radiometric dating techniques quizlet below it and a maximum age on the fossils found above it.
The first attempt to date the tuff was in by two recognized authorities in potassium-argon dating F. They first determined that the tuff was between million and million years old. However according to the supposed evolution of the mammalian fossils found BENEATH the tuff determined it should be around 2 million to 5 million years old.
Since the they didn't have access to the associated fossils there wasn't a way for an radiometric dating techniques quizlet geologist to tell whether they were 'good' or 'bad' dates. Since they didn't have the fossils and under the current conditions an evolutionary geologist could have accepted they were 'good' dates. So what did Fitch radiometric dating techniques quizlet Miller do?
They requested new samples. From pumice radiometric dating techniques quizlet and crystals they found the age of KBS Tuff to be 2. Leakey found skull after the tuff had been dated at 2. This is how he estimated that the skull was 2. In an article a chronology on the hominid-bearing sediments including KBS Tuff was published by a man named Vincent Maglio before skull was announced. He based his work on two lineages of pigs and one of elephant.
Radiometric dating techniques quizlet dates were compatible with those of Miller and Fitch. Maglio's dates were used to confirm their dates. Two years later a third chronology was published with dates that seemed to validity the correlation. Between the different methods. Radiometric dating techniques quizlet the KBS Tuff had been tested five times with four different methods.
So all of the studies seemed to match up but there was one catch. Evolutionary theory would not allow a skull that was so modern in appearance to be so old. Leakey faced a dilemma. He had either found the oldest member of the Homo genus at 2. Therefore he didn't lower it's age. Two more studies that were conducted showed that the age of the tuff was significantly younger. Now that there was major discrepancies in the data the articles cited it was due to getting a 'good' sample.
One that wasn't weathered, altered or acquired from an older rock. What is a good sample and what is a bad sample? One that is "good"will give you dates radiometric dating techniques quizlet are in line with the presuppositions in Radiometric dating techniques quizlet theory. One that is "bad" doesn't give you dates in line with Evolutionary theory. Ten years after the KBS Tuff was first dated the controversy seemed to settle.
However the controversy was settled in by pigs. A conference held in on anthropology and geology would throw a wrench in the validity of radiometric dating techniques quizlet dating. Basil Cooke had studied pig sequences in Ethiopia and Tanzania and had concluded that the dating done in Kenya was off by hundred thousand years. After the conference many anthropologists rejected the data gathered from previous dating.
The dates didn't match up with the supposed evolution of humans and pigs. The direct answer to the dating problems was said to be the evolution of pigs. The evidence is well less than compelling. Basil Cooke organized twenty different types of pigs into three groups. Well two of the groups had a hypothetical answer and each species had no between them. Two studies in and on the date of KBS Tuff greatly criticized the earlier studies.
The objectivity and validity of the methods was under skepticism. This timeline shows the two misleading facts about radiometric dating. No matter how carefully a scientist selects a rock if the dating of the rock is not accurate two matters radiometric dating techniques quizlet brought up: Fossil discovery allows paleoanthropologists a great deal of control over the results. With these two things we get a misleading picture of the compliance of the fossil record and human evolution.