Seismic evidence of two cryptic sutures in Northwestern Australia: Implications for the style of subduction during the Paleoproterozoic assembly of Columbia

• Published in: Earth and planetary science letters 2022-02, Vol.579, p.117342, Article 117342
• Main Authors: Zhao, Liang, Tyler, Ian M., Gorczyk, Weronika, Murdie, Ruth E., Gessner, Klaus, Lu, Yongjun, Smithies, Hugh, Li, Tingzi, Yang, Jianfeng, Zhan, Alex, Wan, Bo, Sun, Baolu, Yuan, Huaiyu
• Format: Article
• Language: English
• Subjects: continental collision; continental lithosphere; craton; passive-source seismic imaging; the Percival Lakes Province; upper mantle dipping reflectors
• ISSN: 0012-821X; 1385-013X
• DOI: 10.1016/j.epsl.2021.117342

•Two cryptic sutures are revealed by Earthquake seismic imaging in NW Australia.•In between a distinct Percival Lakes Province is defined.•The northern suture recorded the amalgamation of the WAC with the NAC.•A dipping upper mantle structure is present beneath the southern suture.•The dipping structure is interpreted to result from a relict subduction at 1.9 Ga. Plate tectonics, including rifting, subduction, and collision processes, was likely to have been different in the past due to the secular cooling of the Earth. The northeastern part of the West Australian Craton (WAC) has a complex Archean and Paleoproterozoic tectonic history; therefore, it provides an opportunity to study how subduction and collision processes evolved during the emergence of plate tectonics, particularly regarding the assembly of Earth's first supercontinent, Columbia. Because the northeastern boundary of the WAC and the southwestern boundary of the North Australian Craton (NAC) are covered by the Phanerozoic Canning Basin, the regional tectonic evolution has remained enigmatic, including how many tectonic elements were assembled and what may have driven rifting and subsequent collision events. Here, we use new passive-source seismic modeling to identify a seismically distinct segment of the lithosphere, the Percival Lakes Province, which lies east of the Pilbara Craton and is separated by two previously unknown southeast-trending lithosphere scale Paleoproterozoic sutures. We interpret that the northeastern suture, separates the Percival Lakes Province from the NAC, records the amalgamation of the WAC with the NAC. The southwestern suture separates the PLP from the reworked northeastern margin of the Pilbara Craton, including the East Pilbara Terrane and the Rudall Province. A significant upper mantle dipping structure was identified in the southwestern suture, and we interpret it to be a relic of subduction that records a previously unknown Paleoproterozoic collision that pre-dated the amalgamation of the WAC and NAC. By comparing our findings with previously documented dipping features, we show that the Paleoproterozoic collisions are seismically distinguishable from their Phanerozoic counterparts.