Magmatic minerals of the eastern Sunda arc, Indonesia

Abstract

The eastern Sunda arc is one of the most prospective Cu-Au magmatic belts in the world with four world class copper-gold porphyry deposits: Batu Hijau (1.64 Gt at 0.44% Cu, 0.35 g/t Au), Elang (2.42 Gt at 0.31% Cu, 0.33 g/t Au), Tumpangpitu (1.90 Gt at 0.45% Cu, 0.45 g/t Au ) and Hu’u (1.70 Gt at 0.89% Cu, 0.49 g/t Au). Magmatism along the belt spans the late Oligocene to Pliocene, with the majority of giant porphyry systems forming in the last 5 m.y. New geochronology confirms a consistent east-younging in central and eastern Java from Trenggalek (~15 Ma) through Salakan (~8.5 Ma) and Jember (~7 Ma), to the pre-mineralization phases (~6.5 Ma) and syn-mineralization phases (~4 Ma) at Tumpangpitu. ). New ages on Lombok show a westward younging in SW Lombok from Kuta, Plambik and Lembar in the east (20-17.5 Ma) through Songkang (~10-8 Ma), Selodong (~7.5 Ma) and Brambang (~7 Ma). On Sumbawa, there is a general younging from west to east from Nangka (~6.5 Ma), Naga Emas (~5 and 3.5 Ma) to Batu Hijau (~4.5-3.5 Ma) and the Elang district (~3.0 to 2.5 Ma). Middle-Micoene intrusions on Lombok (Lembar, Plambik, Kuta) were previously unknown, and extend the limit of Middle-Miocene magmatism to Lombok. [...]