Rocks that are Miocene or older and have always been or were once part of the Australian Plate
Transitional
Metamorphic rocks—typically of Cretaceous age. Note however, these typically have poor age control and more often than not were classified on the basis that these are deformed/metamorphic rock
Mesozoic ultramafic rocks
Refers to Cretaceous or older ultramafic rocks
Accreted Pacific Plate affinity
Cretaceous to Early Miocene mafic volcanic rocks that likely accreted to New Guinea's northern margin during the Cretaceous, or during the Eocene–Oligocene. This classification contains some ultramafic rock
Post collisional volcanics and intrusives
Refers to volcanic and plutonic rocks that are Miocene age or younger
Miocene or younger rocks that overlie Pacific Plate
Refers to sedimentary rocks and carbonates that are Miocene or younger that overlie what was once likely part of the Pacific Plate (and therefore assumed to also be representative of the ‘Accreted Pacific Plate affinity’ category)
Pliocene or younger rocks that overlie the Australian Plate
Refers to sedimentary rocks and carbonates that are Pliocene or younger that overlie what is or was once part of the Australian Plate (and therefore assumed to also be representative of the ‘Uplifted Australian Plate affinity’ category)
