On May 18, 1980, a tremendous landslide on the northern side of Mount St.Helens in Washington state uncapped a violent volcanic eruption, completely altering the surrounding landscape.Phenocrysts of orthopyroxene, hornblende and plagioclase are interpreted to have occluded argon within their mineral structures deep in the magma chamber and to have retained this argon after emplacement and solidification of the dacite.The amount of argon occluded is probably a function of the argon pressure when mineral crystallization occurred at depth and/or the tightness of the mineral structure.A survey of anomalous K-Ar "dates" indicates they are common, particularly in basalts, xenoliths and xenocrysts such as diamonds that are regarded as coming from the upper mantle.
This has significant implications for the validity of K-Ar and Mt Ngauruhoe is an andesite stratovolcano of 2,291 m elevation, rising above the Tongariro volcanic massif within the Tongariro Volcanic Center of the Taupo Volcanic Zone, North Island, New Zealand (Figure 1) [38, 97].
The mountain also provided a clear reason to distrust the reliability of radiometric dating.
A new rock cap atop the mountain that formed after the 1980 eruption should have shown it to be on the order of tens of years.
For more than three decades potassium-argon (K-Ar) and argon-argon (Ar-Ar) dating of rocks has been crucial in underpinning the billions of years for Earth history claimed by evolutionists. Lassen plagioclase, California (AD 1915) 0.11±0.03 Ma Sunset Crater basalt, Arizona (AD 1064-1065) 0.27±0.09 Ma; 0.25±0.15 Ma Akka Water Fall flow, Hawaii (Pleistocene) 32.3±7.2 Ma Kilauea Iki basalt, Hawaii (AD 1959) 8.5±6.8 Ma Mt.
Critical to these dating methods is the assumption that there was no radiogenic argon ( Hualalai basalt, Hawaii (AD 1800-1801) 1.6±0.16 Ma; 1.41±0.08 Ma Mt. Stromboli, Italy, volcanic bomb (September 23, 1963) 2.4±2 Ma Mt.