Published April 1978 | Version v1
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Potassium-argon technology

Description

The main features of the method of processing rocks and minerals and measuring the extracted argon, for the purpose of potassium-argon dating are described. It differs in several respects from the conventional one, as described, f.i., in Dalrymple and Lanphere's monography. Principally it was established that the continual purification of the gases in the mass spectrometer cell during the measurement, stops the peaks of current drift, and renders them representative of the introduced argon. This allows on the one hand to improve the reliability and accuracy of measurements, on the other hand to get rid of the isotopic dilution method, with 38 A as a spike. Moreover the reliability of the radiogenic argon is improved by taking into account the mislinearness of the M.S. response. All this results in a higher performance of the K/Ar dating method, especially in the recent ages range. The technological side of the problem was only dealt with

Availability note (English)

MF available from INIS under the Report Number.

Abstract (French)

On decrit dans leurs grandes lignes le traitement des roches et mineraux et les mesures portant sur l'argon qu'on en extrait, aux fins de datation par la methode potassium-argon. Notre mode operatoire s'ecarte a plusieurs egards du mode operatoire traditionnel decrit dans les monographies de Schaeffer et Zahringer, d'une part, de Dalrymple et Lanphere, d'autre part. En particulier, on montre qu'en poursuivant la purification de l'argon pendant la mesure au spectrometre de masse, les signaux restent constants dans le temps et sont directement representatifs de l'argon introduit. Ceci permet, a la fois d'ameliorer la precision des mesures, et de dispenser du marquage a l'argon 38. La prise en consideration de la non-linearite de la reponse du spectrometre de masse accroit la fiabilite de la determination de l'argon radiogenique. Il resulte de tout ceci une amelioration globale de la methode K/A, qui se traduit notamment par l'extension de son domaine d'application en direction des ages recents. On traite exclusivement l'aspect technologique et instrumental du probleme

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Additional details

Additional titles

Original title (French)
Technologie potassium-argon

Publishing Information

Imprint Pagination
35 p.
Report number
CEA-R--4908

INIS