The Salawati area constitutes the oil-producing western extremity of Irian Jaya, Indonesia. It lies in the complex area of interaction of three major crustal plates: the Pacific oceanic plate on the north, the Australian continental plate on the southeast, and the Asian continental plate on the southwest.

Geometric, geomorphologic, geologic, and geophysical evidences strongly indicate that Salawati Island was attached to the Irian Jaya mainland during the time of Miocene-lower Pliocene reef development, and that it was separated in middle Pliocene to Pleistocene time, opening the Sele Strait rift zone. The island moved 17.5 km southwestward after an initial counterclockwise rotation of 13°.

The rift zone is subsequent to the creation of the large left-lateral Sorong fault zone that is part of the transitional area separating the westward-moving Pacific plate from the relatively stable Australian plate. The motion was triggered during a widespread magmatic intrusion of the Sorong fault zone, when the basalt infiltrated a right-lateral fault system in the area of the present Sele Strait.

Rifting along three parallel major left-lateral strike-slip faults can be traced from the Sele Strait to the southern part of Salawati Island. The amount of relative displacement increases from the southeast fault to the northwest fault.

These faults later became the site of important down-to-the northwest, normal faulting to accommodate the subsidence resulting from the load of Pliocene-Pleistocene deposits derived from the high northern basaltic mountains.

Pliocene-Pleistocene diastrophism thus has defined several zones of varied structural character: the Sele Strait, the Irian Jaya mainland, Salawati Island, and their respective surroundings.

If Salawati Island is placed in its former Irian Jaya frame, and the northern compartment of the left-lateral Sorong fault zone is moved back east, the Miocene landscape appears to be characterized by a widespread carbonate development with reefs thriving at the edge of an early New Guinean landmass facing an open sea on the west. The original distribution of reefs is somewhat different from the present arrangement.