The Ar variation of K-Ar dating grew out of iodine-xenon dating studies of meteorites by Jeffery and Reynolds (1961); also see Reynolds, 1963). In these studies the isotopic ratios of all the noble gases (He, Ne, Ar, Kr, and Xe) of neutron-irradiated meteorites were measured. One year later Boltwood (1907) developed the chemical U-Pb method. These first "geochronology studies" yielded the first absolute ages from geologic material and indicated that parts of the Earth's crust were hundreds of millions of years old. Sur les radiations invisibles mises par les corps phosphorescents.
In these early studies the vertical succession of sedimentary rocks and structures were used to date geologic units and events relatively. Trace-element determinations and potassium-argon dating by mass spectroscopy of neutron-irradiated samples. Potassium-argon dating by activation with fast neutrons. Following the discovery of radioactivity by Becquerel (1896a,b,c) near the end of the nineteenth century, the possibility of using this phenomenon as a means for determining the age of uranium-bearing minerals was demonstrated by Rutherford (1906). In his study Rutherford (1906) measured the U and He (He is an intermediate decay product of U) contents of uranium-bearing minerals to calculate an age. Ar step-heating dating technique and about the interpretation of the data generated from a step-heating experiment. On the ultimate disintegration products of the radio-active elements. So with their encouragement I will attempt to explain the method and the criteria used to interpret the data generated from a Ar step-heating experiment. See Mc Dougall and Harrison, (1988) for a more extensive discussion on the history and development of Aldrich and Neir Aston, F. Corrections for interfering isotopes in the Ar stepwise degassing technique. The geochronological significance of argon-40/argon-39 age determinations on White Whin from the northern Pennine orefield. A new approach to radio-isotopic dating in orogenic belts.