East Asia plate tectonics since 15 Ma: Constraints from the Taiwan region

Jean Claude Sibuet, Shu Kun Hsu, Xavier Le Pichon, Jean Pierre Le Formal, Donald Reed, Greg Moore, Char Shine Liu

Research output: Contribution to journalArticlepeer-review

159 Scopus citations

Abstract

15 Ma ago, a major plate reorganization occurred in East Asia. Seafloor spreading ceased in the South China Sea, Japan Sea, Taiwan Sea, Sulu Sea, and Shikoku and Parece Vela basins. Simultaneously, shear motions also ceased along the Taiwan-Sinzi zone, the Gagua ridge and the Luzon-Ryukyu transform plate boundary. The complex system of thirteen plates suddenly evolved in a simple three-plate system (EU, PH and PA). Beneath the Manila accretionary prism and in the Huatung basin, we have determined magnetic lineation patterns as well as spreading rates deduced from the identification of magnetic lineations. These two patterns are rotated by 15°. They were formed by seafloor spreading before 15 Ma and belonged to the same ocean named the Taiwan Sea. Half-spreading rate in the Taiwan Sea was 2 cm/year from chron 23 to 20 (51 to 43 Ma) and 1 cm/year from chron 20 (43 Ma) to 5b (15 Ma). Five-plate kinematic reconstructions spanning from 15 Ma to Present show implications concerning the geodynamic evolution of East Asia. Amongst them, the 1000-km-long linear Gagua ridge was a major plate boundary which accommodated the northwestward shear motion of the PH Sea plate; the formation of Taiwan was driven by two simple lithospheric motions: (i) the subduction of the PH Sea plate beneath Eurasia with a relative westward motion of the western end (A) of the Ryukyu subduction zone; (ii) the subduction of Eurasia beneath the Philippine Sea plate with a relative southwestward motion of the northern end (B) of the Manila subduction zone. The Luzon arc only formed south of B. The collision of the Luzon are with Eurasia occured between A and B. East of A, the Luzon arc probably accreted against the Ryukyu forearc.

Original languageEnglish
Pages (from-to)103-134
Number of pages32
JournalTectonophysics
Volume344
Issue number1-2
DOIs
StatePublished - 2002

Keywords

  • 15 Ma
  • East Asia
  • Plate tectonics
  • Taiwan

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