To explore the dynamic mechanism of continental rifting within a convergent setting, we determine the first P wave radial anisotropic tomography beneath the Woodlark rift in southeastern Papua New Guinea, which develops within the obliquely colliding zone between the Australian and southwest Pacific plates. The rift zone is depicted as localized low-velocity anomalies with positive radial anisotropy, which rules out a dominant role of active mantle upwelling in promoting the rift development and favors passive rifting with decompression melting as main processes. Downwelling slab relics in the upper mantle bounding the rift zone are revealed based on observed high-velocity anomalies and negative radial anisotropy, which may contribute to the ultra-high pressure rock exhumations and rift initiation. Our observations thus indicate that the Woodlark rift follows a passive model and is mainly driven by slab pull from the northward subduction of the Solomon plate.


Geosciences and Geological and Petroleum Engineering


National Science Foundation, Grant 1919789

Keywords and Phrases

decompression melting; radial anisotropy; slab downwelling; slab-pull; ultra-high pressure rock; Woodlark rift

International Standard Serial Number (ISSN)

1944-8007; 0094-8276

Document Type

Article - Journal

Document Version

Final Version

File Type





© 2023 Wiley; American Geophysical Union, All rights reserved.

Publication Date

16 Mar 2022