Papua New Guinea Geology Papua New Guinea occupies the eastern
half of the island of New Guinea (the world's largest and
highest tropical island), as well as several nearby
archipelagos. The country is rugged, with glacier capped
mountains that reach 4500 meters and the deepest caves in the
Southern Hemisphere. New Guinea forms the northern edge of the
Australian plate and is separated from Australia by the shallow
Torres Straits the two land masses were connected during low sea
level stands and share similar animals and plants. New Guinea's
biota is also similar to that of the islands to the north, which
are actively colliding with New Guinea. In fact, much of the
northern coast of New Guinea is composed of accreted islands
that docked as Australia moved north and the Pacific Plate moved
west. These accreted terrains probably had unique snail faunas
similar to islands offshore of New Guinea today. Papua New
Guinea's high land snail diversity reflects the rugged landscape
and many different terrains and islan