Abstract

The fifth annual conference and AGM of the Mineral Deposits Studies Group was held at the Uniuersity of Exeter on 13–15 December 1979 in conjunction with geologists working on the IGCP project 'Mineralization associated with acid magmatism' (MAWAM). It at- tracted about 100 participants from 20 counties.The meeting was organized by M . Stone, A. M . Euans and P. Garrard.

In the context of magmatic evolution, Smith & Miller traced the path of Sn in the peraluminous Halifax pluton, Nova Scotia, showing that it concentrated initially in the silicate melt and eventually partitioned into aqueous hydrothermal fluid. Also in Nova Scotia, Chatterjee noted that the principal Sn mineralization was associated with para-intrusive granitoids and that cassiterite in albitized granites differed from that in greisenized granites. In Nigeria, Bowden & Kinnaird established that the economic elements concentrated in residual peralkaline fluids. Higher temperature fluids caused Nb mineralization and albitization, whereas lower temperature fluids (400–250°C) were associated with Sn-Zn mineralization and potassic alteration.

Several papers concentrated almost entirely on hydrothermal fluids. Taylor & Fryer showed that the changing characteristics of the fluids could be monitored through the behaviour of the rare earth elements. They used an ion exchange and fluorescence technique that could produce 300–500 analyses per month. Haapala & Kinnunen classified the nature of fluids from data on inclusions. Norman & Trangcotchasan used a technique which yielded information on the pressure as well as the temperature of fluid inclusions and showed that salinity and CO2-content varied during the mineralizing period.

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