摘要： 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. 出版者： Taiwan: 中華民國地球科學學會 出版日期： 2012-12-01 出處： TAO : Terrestrial, atmospheric, and oceanic sciences, 2012-12, Vol.23 (6), p.657-669 資源來源： Chinese Electronic Periodical Services (CEPS) 版權： 2012. This work is licensed under https://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License. 識別號： ISSN: 1017-0839 識別號： ISSN: 2223-8964 識別號： ISSN: 2311-7680 識別號： EISSN: 2311-7680 識別號： DOI: 10.3319/TAO.2012.07.06.01(TT)
