<![CDATA[The Sintang intrusives are widely exposed in West Kalimantan, and as reported by previous workers, consisting of high level intrusives of stocks, plugs, dykes and sills of microdiorite, microgranodiorite, granite/ microgranite, quartz diorite, dacite, andesite, and minor rhyolite and rhyodacite. However, a careful study of published geochemical data gives a result that the rocks are of adakitic type. Considering the tectonic development of the South China Sea and northwest Kalimantan, the adakite was probably originated from magma as a result of melting of the subducted South Cina sea oceanic crust beneath Kalimantan continent. The subduction started in the Late Oligocene when the crust was still young. Keywords : adakite, Sintang, intrusive, Late Oligocene]]>
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