Tectonic, sedimentary, and volcanic evolution of a back-arc basin in the East Sea (Sea of Japan)

• Published in: Marine geology 2014-06, Vol.352, p.70-88
• Main Authors: Yoon, S.H., Sohn, Y.K., Chough, S.K.
• Format: Article
• Language: English
• Subjects: back-arc basin; continental rifting; East Sea; pull-apart; tectonics; Ulleung Basin
• ISSN: 0025-3227; 1872-6151
• DOI: 10.1016/j.margeo.2014.03.004

This paper focuses on the tectonic, sedimentary, and volcanic evolution of a unique back-arc basin (Ulleung Basin) in the southwestern part of the East Sea (Sea of Japan). The basin consists of thick extended continental (or transitional) crust and an overlying sedimentary succession (4–8km thick), with interlayered volcanic flows and sills, defining a number of seismic units of variable reflection characteristics. The northern margin is bounded by faulted continental blocks (South Korea Plateau) with isolated basement lows and sub-basins with intruded and extruded volcanics, whereas the southern margin is underlain by deep-seated basement with a thick (>8km thick) sedimentary succession. The western margin is bounded by a series of strike-slip and normal faults produced by NNW–SSE-directed dextral movements. These structural features suggest a south–southeastward drift of the southwestern Japanese Arc away from the South Korea Plateau during the Early to Middle Miocene, involving large-scale right-lateral strike-slip deformation along the western margin, akin to pull-apart basin formation. During the back-arc opening, the thinned continental crust was largely modified by intrusive volcanics under tensional stress regime. The volcanics also extruded across the axis of extension as well as along the boundary faults on the west. In the Middle to Late Miocene, major faults in the southern and western margins were inverted, forming partial closure of the basin especially in the southern part, although the plateau in the northern margin experienced continuous subsidence. The Ulleung Basin thus provides an example of an immature back-arc basin which experienced a rather brief episode of rifting and extension followed by closure due to tectonic inversion. •It focuses on the tectonic, sedimentary, and volcanic evolution of a back-arc basin.•The basin formed by right-lateral tensional stress in the Early Miocene.•The thinned continental crust was largely modified by intrusive volcanics.•The basin was partly closed due to the tectonic inversion in the Middle Miocene.•The basin provides an example of an immature back-arc basin.