Paleocene Pacific Plate reorganization mirrored in formation of the Suvarov Trough, Manihiki Plateau

Abstract

The Suvarov Trough is a graben structure that deviates from the Danger Islands Troughs within the Manihiki Plateau, a Large Igneous Province (LIP) located in the Central Pacific. New high‐resolution seismic reflection data provide evidence that the graben formed in two phases during the Paleocene (65–45 Ma). In a first phase extension occurred in southwestward direction, pulling apart the northern part of the Suvarov Trough and a parallel trending unnamed trough. In a second phase a change of extensional force direction occurred from southwest to west‐northwest, forming the southern part of the Suvarov Trough that extends onto the High Plateau. The formation of the Suvarov Trough is accompanied by a series of normal fault systems that apparently formed simultaneously. Comparing the seismic results to existing Pacific paleo strain reconstructions, the timing of increased strain and local deformation direction fits well to our findings. We thus suggest that the multiple strike directions of the Suvarov Trough represent an extensional structure that was caused by the major, stepwise Pacific Plate reorganization during the Paleocene.

Building and breaking a large igneous province: An example from the High Arctic

“…The rifting and subsequent seafloor spreading in the Makarov Basin broke apart the HALIP centered over the proto‐Alpha Ridge and left the ARWP isolated from the Alpha Ridge (Figure ). Similar rifting within large igneous plateaus has been reported from the Manihiki Plateau [ Nakanishi et al ., ; Pietsch and Uenzelmann‐Neben , ] and the Kerguelen Plateau [ Rotstein et al , ; Whittaker et al , ]. We speculate that the rotational‐translational movement of the ARWP block was controlled by the F1–F3 fault lineaments (Figure d), which probably continue toward the Chukchi Plateau, Chukchi Basin, Mendeleev Ridge, and East Siberian Shelf.…”

Syn‐Drift Plate Tectonics

“… Extensional tectonics in seismic reflection profiles. (a, b, c, and d) Bathymetric maps of the OJP, SR, HR, and MP and locations of the marine seismic reflection profiles including major extensional structures (Phinney et al., 1999; Pietsch & Uenzelmann‐Neben, 2016; Zhang et al., 2015). (e and f) Seismic reflection profiles (a–a´) from the OJP (Phinney et al., 1999).…”

“…(j and k) Seismic reflection profile (e–e´) from the MP. The cross section cuts the Suvarov Trough, grabens, and normal faults (Pietsch & Uenzelmann‐Neben, 2016).…”

The Manihiki Plateau—a key to missing hotspot tracks?

“…Fault systems occurred, showing deformation of the sequences associated with the LIP formation, particularly in the southern High Plateau and the western and eastern margins, whereas the northern High Plateau remained undisturbed (Pietsch & Uenzelmann-Neben 2015). They show tectonic faulting of the basement after the initial formation period (∼65-45 Ma), probably caused by Pacific Plate reorganization (Pietsch & Uenzelmann-Neben 2016). Since the middle Eocene, tectonism and magmatism of the MP has become quiet until a Neogene magmatic activity occurred, which is discussed in here.…”

“…In contrast, volcanism that is not driven by a point source cannot explain the distribution of diapirs for the following reason: The diapirs are not preferentially distributed within the entire southwestern and western High Plateau, which is an area that was strongly tectonically faulted by break-up processes of the Hikurangi Plateau (Davy et al 2008) and southwestern extension due to the Palaeocene Plate reorganization (Pietsch & Uenzelmann-Neben 2016). The resulting disturbed volcanic basement (Units 3 and 4) promotes potential pathways for ascending magma, preferentially along ancient sills and dykes (Le Corvec et al 2013).…”