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在巽他岛弧和北西澳大利亚之间,即岛弧/大陆碰撞带西部,活动的岛弧火山正喷发着铁镁质火山岩,其系列为:钙碱性玄武岩-橄榄粗面玄武岩-白榴岩。沿巴厘(Bali)-佛罗勒斯(Flores)一线,这些铁镁质火山岩中 K、Rb、Sr、Ba、La 和 Nb 显示三重富集。越靠近碰撞带,富集与~(81)Sr/~(86)Sr 的增大和~(143)Nd/~(144)Nd 的减小关系越明显。地球化学和同位素资料表明:岛弧火山有两个物质来源。一个产生贫钾组元素的物质,具有相对低的~(87)Sr/~(86)Sr值(<0.704)和高~(143)Nd/~(144)Nd 值;另一个产生富钾组元素的物质,具有相对高的~(87)Sr/~(86)Sr 值(<0.707)和低~(143)Nd/~(144)Nd 值。
Between the 巽ttau arc and North Western Australia, the western part of the island arc / continental collision belt, the active island arc volcano exudes a magnesian volcanic rock in the series: Calc-alkaline basalts - Olive rough basalts - white garnet. Along the Bali-Flores line, K, Rb, Sr, Ba, La and Nb in these mafic volcanic rocks show triple enrichment. The closer to the collision zone, the greater the relationship between enrichment and the decrease of ~ (81) Sr / ~ (86) Sr and ~ (143) Nd / ~ (144) Nd. Geochemical and isotopic data suggest that the island arc volcano has two sources of matter. One of the elements that produce the poor potassium group has a relatively low ~ (87) Sr / ~ (86) Sr value (<0.704) and a high ~ (143) Nd / ~ (144) Nd value; Element with a relatively high ~ (87) Sr / ~ (86) Sr value (<0.707) and a low ~ (143) Nd / ~ (144) Nd value.