Intrusion related Cu/Au
mineralisation is localised in Pacific
Rim island arcs by arc parallel, termed
accretionary structures; or arc normal,
termed transfer structures. In Papua
New Guinea, NE trending transfer
structures, evident on Landsat imagery,
represent deep crustal fractures which
have facilitated dextral rotation of
the mainland during oblique plate
collision. Major structures localise
intrusion centres, and by rotation,
develop ore hosting dilational environ-
ments in subsidiary structures. While
transfer structures localise the
Porgera, Wafi and Yandera porphyry
centres, the Frieda Porphyry and
associated Nena high sulphidation Cu/Au
mineralisation are localised by
accretionary structures. The Bulolo
Graben, which hosts the Morobe
Goldfield, developed during intra arc
rifting aided by movement on transfer
structures. Crustal thinning has
initiated magmatism with which diatreme
breccias and fracture controlled
mineralisation are associated.