Potassium argon k ar dating
Argon-39 has been used for a number of applications, primarily ice coring.
It has also been used for ground water dating (Oeschger et al., 1974).
By virtue of its being a noble gas, it is relatively unreactive.This is not only true for recent and young volcanics, but for ancient volcanics such as the Middle Proterozoic Cardenas Basalt of eastern Grand Canyon. In conclusion, the fact that all the primordial argon has not been released yet from the earth's deep interior is consistent with a young Earth. Also, when samples of volcanic rocks are analyzed for K-Ar and Ar-Ar "dating," the investigators can never really be sure therefore that whatever K since their formation, or whether some or all of it came from the mantle with the magmas. Weis, "Helium, Neon and Argon Isotope Systematics in Kerguelen Ultramafic Xenoliths: Implications for Mantle Source Signatures," S. If so, then the K-Ar and Ar-Ar "dating" of crustal rocks would be similarly questionable.When muscovite (a common mineral in crustal rocks) is heated to 740°-860°C under high Ar pressures for periods of 3 to 10.5 hours it absorbs significant quantities of Ar, producing K-Ar "ages" of up to 5 billion years, and the absorbed Ar is indistinguishable from radiogenic argon ( In other experiments muscovite was synthesized from a colloidal gel under similar temperatures and Ar pressures, the resultant muscovite retaining up to 0.5 wt% Ar at 640°C and a vapor pressure of 4,000 atmospheres.