February 2006 LIP of the Month

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Corresponds to events #16, #19, #20, #21 in LIP record database.

Ontong Java - Manihiki - Hikurangi Were Originally One Plateau

Brian Taylor
Dept. of Geology and Geophysics,
School of Ocean and Earth Science and Technology
University of Hawaii
Honolulu, Hawaii 96822 USA

Published in January 2006 in Earth and Planetary Science Letters.

Download full article in pdf format here.

New seafloor fabric data indicate that the OJP, MP and HP (Fig. 1) formed as one.

Figure 1: Location of the Ontong Java Plateau (OJP), Manihiki Plateau (MP), Hikurangi Plateau (HP), and Robbie Ridge (RR) (outlined in red) that were a single plateau 120 Ma, prior to seafloor spreading in the Ellice Basin (EB) and about the Osbourn Trough (OT). White lines depict abyssal hill seafloor fabric interpreted from swath bathymetry data. Black box locates Fig. 2. Other symbols as in Taylor (2006).

The data support previous interpretations that the Osbourn Trough is the relict of the spreading center that separated the MP and HP but indicate that closely spaced, large offset, fracture zones in the Ellice Basin bound former right-stepping spreading segments that separated the OJP and MP (e.g., Fig. 2).

Figure 2: Illuminated multibeam bathymetry swaths with black contours every kilometer. Wide swath data, labeled with cruise name, reveal abyssal hill fabrics (interpolated in red dashes) at sub-orthogonal angles to the fracture zones, several of whose azimuths are shown with black dashes. The two dominant fracture zone sets (060°±3° and 072°±3°) form V-shaped intersections in the Nova-Canton Trough (NCT) and east of Rawaki. Clipperton Fracture Zone (CFZ).

Pacific-Farallon and Pacific-Aluk spreading removed additional former plateau fragments to the east and south-southeast of the MP, together with the symmetric conjugates to the extant Phoenix magnetic lineations.

Reference: Taylor, B. 2006. The single largest oceanic plateau: Ontong Java-Manihiki-Hikurangi. Earth and Planetary Science Letters, v. 241, p. 372-380.