Research ArticleGEOPHYSICS

Intraoceanic subduction spanned the Pacific in the Late Cretaceous–Paleocene

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Science Advances  08 Nov 2017:
Vol. 3, no. 11, eaao2303
DOI: 10.1126/sciadv.aao2303
  • Fig. 1 Bathymetry and topography of the northwest Pacific (GEBCO 2014, www.gebco.net).

    Thin black lines are isochrons from Seton et al. (14), and dense isochrons between chrons 24 and 13 (this study) are based on global magnetic anomaly picks (35). Isochron M0 south of the Kuril (Kur.) Trench is interpreted from the World Digital Magnetic Anomaly Map (2007) (www.wdmam.org). White dashed line highlights the Kuril and Aleutian trenches as reconstructed in Fig. 3. Labeled place names are mentioned in the text. KA, Kronotsky arc; OA, Olutorsky arc; TA, Tokoro arc.

  • Fig. 2 Conventional Late Cretaceous–Eocene reconstructions of the North Pacific realm.

    In these reconstructions, the Pacific-Izanagi ridge persists at the northern edge of the Pacific plate until being subducted at ~55 Ma. The Pacific plate shows northerly motion from ~80 to 47 Ma (toward the Pacific-Izanagi ridge) and northwesterly motion after 47 Ma. Mantle reference frame reconstructions, plate boundaries, and velocities according to Müller et al. (15).

  • Fig. 3 Alternative Late Cretaceous–Eocene reconstructions.

    Our model presented in a paleomagnetic reference frame (32) (left) and a mantle reference frame (13) (right), using newly defined plate boundaries based on geologic, paleomagnetic, and tomographic data; the remaining boundaries are from Seton et al. (14) (Materials and Methods). The retrodeformation of terranes was not attempted, except for a simplified unbending of the KA (dashed present-day outline). Left: Colored stars show mean paleomagnetically determined paleolatitudes for the intraoceanic arcs, with error margins denoted by longitudinal bars (dashed lines include error from results uncorrected for inclination shallowing); reference paleomagnetic sites for each arc are shown as yellow circles. Preserved (present-day) isochrons (14) are shown as thin blue lines, and the reconstructed edge of preserved oceanic crust along the Kuril-Aleutian trench (at present day) is denoted by a dotted black line. The location of the Izanagi-Kronos boundary is unknown, but two possible locations are shown as dashed transforms. Right: Mantle-based reconstruction of our model compared against seismic tomographic data assuming average upper and lower mantle sinking rates (Materials and Methods). Tomographic data shown as positive wavespeed voting maps, where the vote count conveys the number of tomographic models that report a significantly positive wavespeed anomaly (greater than the depth-dependent mean positive value) at a given location (Materials and Methods).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/11/eaao2303/DC1

    table S1. Paleomagnetic data from intraoceanic arcs OA, KA, and TA.

    table S2. Example depth-age associations assuming average slab sinking rates of 2.0 and 1.5 cm/year for the upper and lower mantle, respectively.

    table S3. Global P- and S-wave tomography models used to construct the tomographic vote maps shown in Fig. 3.

    References (3653)

  • Supplementary Materials

    This PDF file includes:

    • table S1. Paleomagnetic data from intraoceanic arcs OA, KA, and TA.
    • table S2. Example depth-age associations assuming average slab sinking rates of 2.0 and 1.5 cm/year for the upper and lower mantle, respectively.
    • table S3. Global P- and S-wave tomography models used to construct the tomographic vote maps shown in Fig. 3.
    • References (36–53)

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