Shop Now Radioisotope dating conveys an aura of reliability both to the general public and professional scientists. Can we really trust it? The lava dome at Mount St Helens provides a rare opportunity for putting radioisotope dating to the test. It was one of those experiences that was well worth every exhausting moment! It sits directly over the volcanic vent at the south end of the huge horseshoe-shaped crater that was blasted out of the mountain by the spectacular eruption on 18 May It is made of dacite, a fine-grained volcanic rock that contains a sprinkling of larger, visible crystals, like chopped fruit in a cake.
Actually, the present lava dome at Mount St Helens is the third dome to form since the eruption, the previous two having been blasted away by the subsequent eruptions. During 17 so-called dome-building eruptions, from 18 October to 26 October , thick pasty lava oozed out of the volcanic vent like toothpaste from a tube. There are two reasons. First, radioisotope-dating methods are used on igneous rocks—those formed from molten rock material.
Dacite fits this bill. Fossil-bearing sedimentary rock cannot be directly dated radioisotopically. Second, and most importantly, we know exactly when the lava dome formed. Contrary to what is generally believed, it is not just a matter of measuring the amount of potassium and argon in a volcanic rock sample of unknown age, and calculating a date. Unfortunately, before that can be done, we need to know the history of the rock. It is routinely assumed that there was no argon initially.
We also need to know whether potassium or argon have leaked into, or out of, the rock since it formed. Again, we do not know, so we need to make an assumption. It is routinely assumed that no leakage occurred. The Mount St Helens lava dome gives us the opportunity to check these assumptions, because we know it formed just a handful of years ago, between and The dating test In June of , Dr Austin collected a 7-kg lb block of dacite from high on the lava dome.
A portion of this sample was crushed and milled into a fine powder. Another piece was crushed and the various mineral crystals were carefully separated out. The laboratory was not told that the specimen came from the lava dome at Mount St Helens and was only 10 years old.
The results of this analysis are shown in Table 1. What do we see? First and foremost that they are wrong. Instead, the results ranged from , to 2. Probably some argon was incorporated into the rock initially, giving the appearance of great age.
Note also that the results from the different samples of the same rock disagree with each other. When the method is tested on rocks of known age, it fails miserably. The lava dome at Mount St Helens is not a million years old! At the time of the test, it was only about 10 years old. In this case we were there—we know! How then can we accept radiometric-dating results on rocks of unknown age?
This challenges those who promote the faith of radioisotope dating, especially when it contradicts the clear eyewitness chronology of the Word of God.