Standing roughly in the center of New Zealand’s North Island, Mt Ngauruhoe is New Zealand’s newest volcano and one of the most active. It is not as well publicized as its larger close neighbour MT Ruapehu, which has erupted briefly several times in the last five years.
However, Mt Ngauruhoe is an imposing, almost perfect cone that rises more than 3,300 feet above the surrounding landscape to an elevation of 7,500 feet above sea level. Eruptions from a central 1,300 foot wide crater have constructed the cone’s steep (33°) outer slopes.
Radioactive dating in general depends on three major assumptions:
- When the rock forms (hardens) there should only be parent radioactive
atoms in the rock and no daughter radiogenic (derived by radioactive decay of another element) atoms;
- After hardening, the rock must remain a closed system, that is, no
parent or daughter atoms should be added to or removed from the rock by
external influences such as percolating groundwaters; and
- The radioactive decay rate must remain constant.
If any of these assumptions are violated, then the technique fails and any ‘dates’ are false.
Eleven samples were collected from five recent lava flows during field work in January 1996—two each from the 11 February 1949, 4 June 1954, and 14 July 1954 flows and from the 19 February 1975 avalanche deposits, and three from the 30 June 1954 flow). The darker recent lavas were clearly visible and each one easily identified (with the aid of maps) on the northwestern slopes against the lighter-colored older portions of the cone. All flows were typically made up of jumbled blocks of congealed lava, resulting in rough, jagged, clinkery surfaces.
The potassium-argon (K–Ar) dating method is often used to date volcanic rocks (and by extension, nearby fossils). In using this method, it is assumed that there was no daughter radiogenic argon (40Ar*) in rocks when they formed. For volcanic rocks which cool from molten lavas, this would seem to be a reasonable assumption. Because argon is a gas, it should escape to the atmosphere due to the intense heat of the lavas. Of course, no geologist was present to test this assumption by observing ancient lavas when they cooled,
but we can study modern lava flows.
The samples were sent progressively in batches to Geochron Laboratories in Cambridge, Boston (USA), for whole-rock potassium-argon (K–Ar) dating. Geochron is a respected commercial laboratory, the K–Ar lab manager having a Ph.D. in K–Ar dating. No specific location or expected age information was supplied to the laboratory. However, the samples were described as probably young with very little argon in them so as to ensure extra care was taken during the analytical work.
The ‘ages’ returned from the Geochron Labs range from <0.27 to 3.5 (± 0.2) million years for rocks which were observed to have cooled from lavas 25–50 years ago. One sample from each flow yielded ‘ages’ of <0.27 or <0.29 million years while all the other samples gave ‘ages’ of millions of years.
Because these rocks are known to be less than 50 years old, it is apparent from the analytical data that these K–Ar ‘ages’ are due to ‘excess’ argon inherited from the magma source area deep in the earth.3 Thus, when the lavas cooled, they contained appreciable (non-zero) concentrations of ‘normal’ 40Ar, which is
indistinguishable from daughter radiogenic 40Ar* derived by radioactive decay of parent 40K. This violates assumption (1) of radioactive dating, and so the K–Ar method fails the test.
The radioactive potassium-argon dating method has been demonstrated to fail on 1949, 1954, and 1975 lava flows at Mt Ngauruhoe, New Zealand, in spite of the quality of the laboratory’s K–Ar analytical work. Argon gas, brought up from deep inside the earth within the molten rock, was already present in the lavas when they cooled. We know the true ages of the rocks because they were observed to form less than 50 years ago. Yet they yield ‘ages’ up to 3.5 million years which are thus false. How can we trust the use of this same ‘dating’ method on rocks whose ages we don’t know? If the method fails on rocks when we have an independent eye-witness account, then why should we trust it on other rocks where there are no independent historical cross-checks?
However, we do know Someone who was present when all the earth’s rocks formed—the Creator Himself. He has told us when that was, in His eyewitness account in the Bible’s first book, Genesis, so we know how old all the rocks are. How much better to place our confidence in the Creator who made and knows everything, and who never fails or tells lies, than in a radioactive dating method that has been repeatedly demonstrated to fail and to yield false ages for the earth’s rocks.
Condensed from http://creation.com/radioactive-dating-failure For more details of the testing, results and images of the rocks tested and details of how the blind study was conducted please read the entire article.
 Williams, K., Volcanoes of the South Wind: A Field Guide to the Volcanoes and Landscape of the Tongariro National Park, Tongariro Natural History Society, Turangi, New Zealand, 1994.
 This is true for K–Ar dating, one of the most common
methods, and the one discussed here. The so-called ‘isochron’ technique for dealing with the chemical analyses of the rocks being ‘dated’ attempts to bypass this assumption. A discussion of isochron ‘dating’, along with the associated problems of false (pseudo) isochrons, is outside the scope of this paper, but see Austin,
S.A. (ed.), Grand Canyon: Monument to Catastrophe, Institute for Creation Research, Santee, California, pp. 111–131, 1994.
 Snelling, A.A., The cause of anomalous potassium-argon ‘ages’ for recent andesite flows at Mt Ngauruhoe, New Zealand, and the implications for potassium-argon ‘dating’, In: Walsh, R.E. (ed.), Proceedings of the Fourth International Conference on Creationism, Creation Science Fellowship, Pittsburgh, Pennsylvania, pp. 503–525, 1998
 Dalrymple, G.B., The Age of the Earth, Stanford University Press, Stanford, California, p. 91, 1991.