Kilinailau Trench

Ocean trench in south western Pacific Ocean

New Britain

Papua
New
Guinea

New
Ireland

Solomon
Islands

Solomon
Sea

Kilinailau

Trench

North
Solomon
Trench

Manus
Basin

Ontong
Java
Plateau

West
Melanesian
Trench

Mussau
Trough

Britain
New Trench

Seafloor topographic map of area of Kilinailau Trench. The labelled New Britain Trench to its south-west is the nearest now actively subducting ocean trench.

Approximate surface projection on Pacific Ocean of the relic (ie currently not actively subducting) Kilinailau Trench. While other related relic trenches (light blue) are shown for context, active trenches nearby, which are to the south are not. Click, then mouse-over shows feature names.

The Kilinailau Trench is an oceanic trench delineating the former oceanic crust boundary between the Pacific Plate and the now inactive North Bismarck Plate, in the area to the west of Papua New Guinea.^[1]^[2] To its south west is the inactive North Solomon Trench. The collision of the Ontong Java Plateau in the then subducting oceanic crust of the Pacific Plate, initially to the trench's south-east, changed the plate collision dynamics relative to the then Indo-Australian Plate to the west.^[3] Now the Ontong Java Plateau is just to the east of the trench and its great depth of crust appears to explain why subduction stalled here, and moved to the opposite direction along the far side of New Britain and the Solomons.^[4] The Melanesian ocean arc ridge structures formed when the trench was active are to its west and would include the north eastern part of New Ireland.^[5]

The West Melanesian Trench (Manus Trench), which looks as if it is a western continuation of the Kilinailai Trench, marks the boundary between the Caroline Plate and North Bismarck Plates.^[1] It is, however, disputed whether the Caroline Plate moves independently from the Pacific Plate. If not, the West Melanesian Trench and Kilinailau trenches form the Pacific-North Bismarck boundary together.^[6]

References

^ ^a ^b Tregoning 2002, 2. Tectonic Setting and Existing Models.
^ Davies 2015, pp. 58, 169–170.
^ Davies 2015, pp. 21, 24.
^ Davies 2015, p. 24.
^ Davies 2015, p. 21-24.
^ Tregoning 2002, North Bismarck/Pacific Boundary, p. 6.

Sources

Tregoning, P. (2002). "Plate kinematics in the western Pacific derived from geodetic observations" (PDF). Journal of Geophysical Research: Solid Earth. 107 (B1): ECV 7-1-ECV 7-8. Bibcode:2002JGRB..107.2020T. doi:10.1029/2001JB000406. Retrieved 7 January 2015.
Davies, Hugh L. (2015). "THE GEOLOGY OF BOUGAINVILLE" (PDF). In Anthony J Regan; Helga M Griffin (eds.). BOUGAINVILLE before the conflict. The Australian National University. ISBN 9781921934247. Retrieved 13 August 2023.

Tectonic plates of Southeast Asia–New Guinea (Australian Plate–Pacific Plate Convergence Zone)

Large

Caroline Plate
Philippine Sea Plate
Sunda Plate

Small

West	Burma Plate
Philippines	Philippine Mobile Belt
Indonesia	Banda Sea Plate Bird's Head Plate Halmahera Plate Molucca Sea Collision Zone Molucca Sea Plate Sangihe Plate Timor Plate
New Guinea	Maoke Plate North Bismarck Plate Manus Plate Solomon Sea Plate South Bismarck Plate Trobriand Plate Woodlark Plate

Faults

Trenches
and troughs

Java Trench (Sunda) with Mentawai Trough Sunda Trough Timor Trough
Philippines	Cotabato Trench Manila Trench North Luzon Trough Negros Trench Palawan Trench Philippine Trench East Luzon Trench Sulu Trench
Sulawesi and Moluccas	Aru Trough Banda Trench Ceram Trough Salajar Trough Sangihe Trough Talaud Trough Ternate Trough
Timor	Aur Trough Tanimbar Trough
New Guinea	Ayu Trough Kilinailau Trench Manokwari Trough Lyra Trough Mussau Trough New Guinea Trench Pocklington Trough New Britain Trench (Bougainville) West Caroline Trough West Melanesian Trench