Age and geochemical features of dredged basalts from offshore SW Taiwan: the coincidence of intra-plate magmatism with the spreading South China Sea

Kuo Lung Wang*, Yi Ming Lo, Sun Lin Chung, Ching Hua Lo, Shu Kun Hsu, Huai Jen Yang, Ryuichi Shinjo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)

Abstract

This study reports age and geochemical analyses of basaltic rocks dredged from volcanic seamounts offshore SW Taiwan. 40Ar/39Ar dating results of these rocks show them to be of the early Miocene age of ~22 - 21 Ma. They are evolved alkali basalts that show OIB-type geochemical features similar to post-spreading seamount basalts (14 - 3.5 Ma) in the South China Sea (SCS) and Miocene intraplate basalts on the Penghu Islands (16 - 8 Ma) and NW Taiwan (23 - 9 Ma). Their Sr-Nd-Pb isotope data plot within the range of the SCS seamount basalts that show an EM2-like component in the mantle source. The age and overall geochemical characteristics of the dredged basalts are comparable to those of the Kungkuan basalts, NW Taiwan and Baolai basalts, SW Taiwan, suggesting an extensive alkali basaltic volcanism along the southeastern Eurasian continental margin during the early Miocene that resulted from regional lithospheric extension in association with seafloor spreading in the South China Sea.

Original languageEnglish
Pages (from-to)657-669
Number of pages13
JournalTerrestrial, Atmospheric and Oceanic Sciences
Volume23
Issue number6
DOIs
Publication statusPublished - Dec 2012
Externally publishedYes

Keywords

  • Dredged basalts
  • Eurasian continental margin
  • Geochemistry
  • Miocene
  • South China Sea spreading
  • Taiwan

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