THE CANLAON AND ITS NEIGHBORING VOLCANOS IN THE NEGROS BELT PHILIPPINES

Mt Canlaon is an active, potentially dangerous strato-volcano in the N egros volcanic are on the island of Negros (Philippines). Its volcanic activity during the last 125 years was nearly exclusively restricted to phreatic eruptions and permanent fumarolic emissions. On account of the lack of petrological and chemical data, 52 samples of Negros volc anics have been analysed with regard to their major and trace element composition. The bulk of the rocks are typical calc-alkaline andesites and basaltic andesites, which belong to the high K-calc-alkaline seri es with tendencies to shoshonites. A similar but less K-rich distribut ion is shown by the eruption products of the other volcanoes of Negros , partially plotting into the fields of normal calc-alkaline series. C ompared with other Cenozoic Philippine volcanics, i.e. from the Bicol and Central Luzon Belts and from Hibok-Hibok volcano, the Negros suite differs significantly by its higher levels of K2O. The Negros volcani cs correspond to typically continental or microcontinental association s like those developed in the central Andes or on the North Island of New Zealand. We suppose that the fluids of the subducted Sulu Sea crus t (east of Palawan) may control the isotopic and trace element variati ons in the southwestern Philippine island are, including the generatio n and evolution of the Negros magmas.