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. [...]