Dissertation/Thesis Abstract

Rifting and subduction in the Papuan Peninsula, Papua New Guinea: The significance of the Trobriand Trough, the Nubara strike-slip fault, and the Woodlark rift to the present configuration of Papua New Guinea
by Cameron, Milo Louis, Ph.D., The University of Alabama, 2014, 230; 3620068
Abstract (Summary)

The calculated extension (~111 km) across the Woodlark rift is incompatible with the > 130 km needed to exhume the Metamorphic Core Complexes on shallow angle faults (< 30°) using N-S extension in the Woodlark Basin. High resolution bathymetry, seismicity, and seismic reflection data indicate that the Nubara Fault continues west of the Trobriand Trough, intersects the Woodlark spreading center, and forms the northern boundary of the Woodlark plate and the southern boundary of the Trobriand plate. The newly defined Trobriand plate, to the north of this boundary, has moved SW-NE along the right lateral Nubara Fault, creating SW-NE extension in the region bounded by the MCC's of the D'Entrecasteaux Islands and Moresby Seamount. Gravity and bathymetry data extracted along four transect lines were used to model the gravity and flexure across the Nubara Fault boundary. Differences exist in the elastic thickness between the northern and southern parts of the lines at the Metamorphic Core Complexes of Goodenough Island (Te_south = 5.7 x 103 m; Te_north = 6.1 x 103 m) and Fergusson Island (Te_south = 1.2 x 103 m; Te_north = 5.5 x 103 m). Differences in the elastic strength of the lithosphere also exist at Moresby Seamount (Te_south = 4.2 x 103 m; Te_north = 4.7 x 103 m) and Egum Atoll (Te_south =7.5 x 103 m; Te_north = 1.3 x 104 m). The differences between the northern and southern parts of each transect line imply an east-west boundary that is interpreted to be the Nubara Fault. The opening of the Woodlark Basin resulted in the rotation of the Papuan Peninsula and the Woodlark Rise, strike slip motion between the Solomon Sea and the Woodlark Basin at the Nubara Fault, and the formation of the PAC-SOL-WLK; SOL-WLK-TRB triple junctions. The intersection of the Woodlark Spreading Center with the Nubara Fault added the AUS-WLK-TRB triple junction and established the Nubara Fault as the northern boundary of the Woodlark plate.

Indexing (document details)
Advisor: Goodliffe, Andrew M.
Commitee: Cemen, Ibrahim, Kopaska-Merkel, David, Robinson, Delores, Stowell, Harold
School: The University of Alabama
Department: Geology
School Location: United States -- Alabama
Source: DAI-B 75/08(E), Dissertation Abstracts International
Source Type: DISSERTATION
Subjects: Geology, Geophysics, Plate Tectonics
Keywords: Extension, Metamorphic core complex, Papua New Guinea, Plate boundaries, Strike-slip faulting, Subduction
Publication Number: 3620068
ISBN: 9781303897559
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