Abstract
The central West Philippine Basin (WPB) comprises three contrasting geomorphologic provinces, the mantle-plume type Benham Rise in west, the volcanic arc-type Kyushu-Palau Ridge (KPR) at the east limit, and the in-between central rift hosting the deepest (∼7874 m) rifted seafloor. However, their morphic transit and dynamic interactions remain elusive owing to the insufficiency of relevant data. By incorporating new and previous multibeam bathymetry data fully enveloping the central rift, we synthesized a 3-band, 3-segment seafloor fabric of the central WPB and deduced its formation mechanisms. The bathymetry documents prominent across- and along-axis variations and variable landform assemblages, including: 1) overall trends of abyssal hill lineation swing counter-clockwise from ∼N100/105°E at a distance of 100 km from the fossil rift valley to ∼N85/95°E at a distance of ∼30/50 km, then clockwise to ∼N100/140°E in the rift valley, which recognizes three irregularly bands (I, II, and III ripping into II) and a rotatory spreading fabric; 2) the rift valley narrows westward from ∼85 km wide near the KPR to ∼25 km at Centric Deep, and then fades out to further west, synchronously from magmatic to amagmatic then to failed, indicating a northwestward propagating stirred by the KPR volcanism. Moreover, it is found in the middle segment that three major transform faults bend southwesterly into Southern Band I with their concaves pointing to the Benham Rise. Behaving as pseudo-faults, they are likely triggered by the former magmatism of the Benham Rise. Lying just at the intersection of a relict nodal basin and the western tip of the later PR, the Centric Deep might have resulted from overprinting amagmatic extension on former pull-apart. Thus, the geomorphic fabric featuring high spreading instability reflects strong magma-tectonic intervention by excessive magmatism of mantle plume and subduction arc.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
