Interpretation of seismic refraction data from the southwestern coast of the Papuan Peninsula and the northwest Coral Sea gives consistent results using several inversion techniques. Sediments over the Papuan Plateau are 5 km thick; to the west and northwest they thicken to 10 km along the axes of the Moresby and southern Aure Troughs. Farther out into the Coral Sea, over the Eastern Plateau, they are 1 to 2 km thick. Beneath the sediments, a layer with a P-wave velocity of 6.07 km s^-1 was inferred over the region. It is underlain along the southern coastline of the peninsula by a lower crustal layer with a velocity of 6.9 km s^-1, which is probably also present under the Eastern Plateau. We cannot say whether the lower crustal layer also occurs offshore under the Moresby Trough, but it is not present under the Aure Trough in the north. Intervals where the velocity increases with depth are likely in the lower crust (> 17 km) under the peninsula, but we have insufficient data to say if they are present offshore. The Moho is 27 to 29 km deep along the southwestern coast of the peninsula. It shallows to 19 km under the Moresby Trough and deepens to 25 km under the Eastern Plateau. The crust is therefore continental under the Papuan Peninsula and Eastern Plateau and, excluding the sediments, oceanic under the Moresby Trough. We have examined several tectonic models for the region that imply different stress patterns at the time of formation of the Moresby Trough. We favour one in which northern Australia, the Eastern and Papuan Plateaus and the Papuan Peninsula once formed a continuous, continental crust. With the opening of the Coral Sea Basin, crustal thinning extended northwards along the axis of the Moresby Trough, probably into the Aure Trough. This model implies a regional tensional stress pattern at the time of formation.

A co-operative survey between the Soviet Academy of Sciences and the Australian Bureau of Mineral Resources during 1979 successfully measured the acceleration due to gravity using an absolute apparatus at Sydney, Hobart, Alice Springs, Darwin, and Perth in Australia, and at Port Moresby in Papua New Guinea. The measurements have a precision of about 6 micro Gal and an accuracy of about 15 microGal. Gravity ties to earlier stations allow comparisms with GAG-2 gravity meters, OVM pendulums and IGSN71 results. Gravity differences between cities are generally not significant at the 95 percent confidence level. Gravity differences at individual cities are also not significantly different from zero. The mean difference for all cities could be interpreted as having a component of secular variation of +3.3 ± 1.2 microGal/yr.

A considerable amount of new information obtained since about 1965 has contributed greatly to a fuller understanding of late Cainozoic tectonics and volcanism in Papua New Guinea. The region straddles a complex zone of convergence between the major Indo-Australian and Pacific plates (estimated rates are about 9-14 cm yr^-1), and includes two, and possibly as many as four, minor plates. There are at least six - perhaps as many as ten - plate boundaries in Papua New Guinea. Most of them are zones of convergence, characterised by different components of strike-slip motion; one, and part of another, are ridge transform zones where new sea floor is being created. The Australian continent and Ontong Java Plateau reached the region during the Cainozoic, and may have had a major influence on plate kinematics in the late Cainozoic. Late Cainozoic volcanoes of Papua New Guinea are widely distributed and chemically diverse. Andesite is common, and most volcanic rocks may be classified broadly as arc-trench type; but comendites, intra-plate rhyolites, strongly undersaturated rocks, and basalts similar to those of back-arc basins, are among the rock types represented in some areas.

Consolidated Maritime Boundaries between Australia and Papua New Guinea Diagram AU/PNG-07 Refer to GeoCat 73168 Treaty text and coordinates can be found at: http://www.austlii.edu.au/au/other/dfat/treaties/1985/4.html

Geological and geophysical evidence from a number of studies has established that the Papuan Ultramafic Belt is probably an overthrust sheet of oceanic crust and mantle, with a thicker crustal section than normal oceanic crust. Earlier workers have described the overthrust as the result of north-south compression produced by the northwards movement of the Australian Plate. However, left-lateral faulting of the Belt subsequent to emplacement is evident from the displacement of the main ultramafic bodies. Reconstruction of the Belt by reversing the movements along these faults suggests that the Belt was aligned north-south when originally emplaced. Theoretical cross-sections of the Belt along three profiles were constructed - assuming that is was originally aligned north-south with a shallow easterly dip, and was sheared in a northwesterly direction. The computed gravity and magnetic anomalies along these theoretical cross-sections match the observed anomalies closely. The Belt was probably emplaced 30° south of its present latitude, before the Australian Plate started to move north about 55 m.y. B.P. The thick Cretaceous crust which forms the Belt is thought to extend north under most of the western part of the Solomon Sea, and east along the Woodlark Rise where is has been subject to extensive rifting. The presently exposed part of the Belt is estimated to have been uplifted by up to 10 km.

The R502 series of maps has been replaced by the National Topographic Map Series (NTMS). The R502 series consists of 542 map sheets and covers Australia at a scale of 1:250,000. It was compiled from aerial photography, but only about one quarter of the series was contoured. The standard sheet size is 1 degree of latitude by 1.5 degrees of longitude. Transverse Mercator map projection and Clark 1858 datum were used. Coverage of the country was completed in 1968.

Free Movement for Traditional Activities Including Traditional Fishing under Article 11 and Traditional Customary Rights under Article 12 of the Treaty between Australia and the Independent State of Papua New Guinea concerning Sovereignty and Maritime Boundaries in the area between the two Countries, including the area known as Torres Strait, and Related Matters (1978) Diagram AU/PNG-10 Refer previous GeoCat 70426 Treaty text and coordinates can be found at: http://www.austlii.edu.au/au/other/dfat/treaties/1985/4.html

Territorial sea of Boigu to Saibai Island as established under Annex 1 and in part Article 3 and Annex 3 and depicted in the Treaty between Australia and the Independent State of Papua New Guinea concerning Sovereignty and Maritime Boundaries in the area between the two Countries, including the area known as Torres Strait, and Related Matters (1978) Diagram AU/PNG-11 Refer Geocat 73655 Treaty text and coordinates can be found at: http://www.austlii.edu.au/au/other/dfat/treaties/1985/4.html

This series of maps covers the whole of Papua New Guinea at a scale of 1:250 000 (1cm on a map represents 2.5km on the ground). Each standard map covers an area of 1.5 degrees longitude by 1 degree latitude or about 150km from east to west and 110km from north to south. There are more than 50 special maps in the series and these maps cover a non-standard area some also include imagery and additional narrative information. Typically, where a map produced on standard sheet lines is largely ocean it is combined with its landward neighbour. These maps contain natural and constructed features including road and rail infrastructure, vegetation, hydrography, contours (interval 50m), localities and some administrative boundaries. Some maps are supplemented by relief shading.

This series of maps covers the whole of Australia at a scale of 1:250 000 (1cm on a map represents 2.5km on the ground) and comprises 513 maps. This is the largest scale at which published topographic maps cover the entire continent.