Sedimentation in a complex convergent margin: the Papua New Guinea collision zone of the western Solomon Sea

Gp. Whitmore et al., Sedimentation in a complex convergent margin: the Papua New Guinea collision zone of the western Solomon Sea, MARINE GEOL, 157(1-2), 1999, pp. 19-45
Citations number
Categorie Soggetti
Earth Sciences
Journal title
ISSN journal
0025-3227 → ACNP
Year of publication
19 - 45
SICI code
Bathymetric, sidescan and 'groundtruthed' acoustic facies maps incorporatin g 50,000 km(2) of HAWAII MRI swath and 3.5 kHz data have been used to const ruct a tectono-sedimentary model for sedimentation along the western Solomo n Sea region of the Papua New Guinea collision zone. The southern underthru st plate along the collision zone includes the Morobe and Trobriand tectono -sedimentary provinces. This region has an extensive platform to the east, a narrow shelf, and a moderately steep slope descending to the plate margin . Along the edge of the underthrust plate sediment accumulates mainly in nu merous isolated slope basins and several canyon-fed slope fans. The former are 5 to 20 km across and filled with fine-grained hemipelagic sediment. Th e latter are larger (40 to 70 km across), coarser-grained and elongate alon g the margin. The overriding plate along the Papua New Guinea collision zon e includes the Huon, Finsch, Siassi and New Britain tectono-sedimentary pro vinces. The edge of this plate has no shelf, is very steep, and sediments a ccumulate in fewer isolated slope basins and mon numerous canyon-fed slope fans, which are also elongate along the margin. The basin floor is constrai ned along two elongate deep sea trenches (separated by oceanic lithosphere) . Sediment supply from the northern overriding plate to the basin floor is limited, as most submarine canyons terminate at slope fans, slope basins or terraces. Sediment supply from the southern underthrusting plate is also b elieved to be low, as approximately half of the tributary submarine canyons debouch onto slope fans before joining the axial Markham Canyon. The sedim ent supplied to the western end of the trench is delivered axially down the collisional suture, much of it apparently derived from emergent landmasses to the west. This pattern of sediment delivery implies that the fill in an cient deep water collisional basins may be largely unrelated to terranes on either side of the basin, but derived from terranes further afield. (C) 19 99 Elsevier Science B.V. All rights reserved.