Report of the Mineral Deposits Studies Group Meeting held at Burlington House, 15 May 1979. The meeting was organized by Dr P. R. Ineson.

The varied applications, advantages and disadvantages of Rb-Sr, K-Ar, U-Pb and Pb-Pb analytical dating techniques were outlined by the speakers.

Beckinsale admitted that in the study of the tin granites of SE Asia, the Rb-Sr technique had not been directly applied to the elucidation of the mineralization. In describing the varied environmental, mineralogical and geochemical characteristics of the ‘I’ and ‘S’ types of granites, he noted that the mineralization was either of the finely disseminated type in greisenized hosts or pegmatite vein occurrences. The SE Asian granites had been involved in basinal structures which had undergone a number of re-heating phases. K-Ar isotopic geochronology on the granites had given excessively young ages. It was advanced, therefore, that Rb-Sr techniques were more applicable to dating the intrusion of the granites, while K-Ar techniques may elucidate re-setting events due to subsequent hydrothermal activity.

Wilson reported various techniques which had been applied in order to date the uranium mineralization in northern Sweden. After outlining the general geological history of the Arjeplog–Arvidsjaur–Sorsele uranium province, he indicated that it was characterized by strong sodium metasomatism, development of skarn deposits and the presence of uranium and urano-titanites in both epigenetic and stratabound occurrences. U-Pb analyses on pure uraninite concentrates and whole-rock Pb-Pb dates had been used. The latter produced the most meaningful results, which were equated with the peak of

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