TY - JOUR
T1 - Tectonic affinities of the accreted basalts in southern Taiwan
AU - Chen, Hsin Yu
AU - Yang, Huai Jen
AU - Liu, Yung Hsin
AU - Huang, Kuo Fang
AU - Takazawa, Eiichi
N1 - Funding Information:
We thank Tung-Hsin Su, Yu-Chin Huang, Shih-Wei Wang, and Kung-Suan Ho for assistance with sample collection and preparation, Chia-Ju Chieh and Li-Yun Huang for chemical and isotopic analyses, and Yuki Yoshida and Yoshihiro Enya for XRF analysis. We also appreciate the insightful discussion with Tung-Hsin Su, Miyabi Sakashita and Kuo-An Tung. Comments from anonymous reviewers strengthened the discussion and improved the presentation of this paper. HJY acknowledges the long-term grant support from the Ministry of Science and Technology (MOST) of Taiwan. This research was supported by MOST grants 103103103, 104104104, and 105105105.
Funding Information:
We thank Tung-Hsin Su, Yu-Chin Huang, Shih-Wei Wang, and Kung-Suan Ho for assistance with sample collection and preparation, Chia-Ju Chieh and Li-Yun Huang for chemical and isotopic analyses, and Yuki Yoshida and Yoshihiro Enya for XRF analysis. We also appreciate the insightful discussion with Tung-Hsin Su, Miyabi Sakashita and Kuo-An Tung. Comments from anonymous reviewers strengthened the discussion and improved the presentation of this paper. HJY acknowledges the long-term grant support from the Ministry of Science and Technology (MOST) of Taiwan. This research was supported by MOST grants 103 103 103 , 104 104 104 , and 105 105 105 . Appendix A
PY - 2018/6/1
Y1 - 2018/6/1
N2 - Tectonic affinities of accreted basalts provide constraints on mass transport in convergent boundaries, improving our understandings on the evolution of regional geology. In this study, nineteen accreted basalts from the southernmost tip of Taiwan Island, which is on the convergent boundary between the Eurasian and Philippine Sea Plates, were analyzed for element concentrations as well as Sr, Nd, Hf, and Pb isotope ratios to investigate their tectonic affinities. All the samples contain > 3% LOI, reflecting post-magmatic alteration. LOI and Nb variation diagrams together with comparisons to oceanic basalt compositions indicated that the concentrations of most major elements and Rb, Sr, and Ba were modified by post-magmatic processes to varying extents, while P2O5, REE and HFSE remained immobile. Although some samples show Pb loss, most samples have Pb concentrations not affected by post-magmatic processes. Isotope ratios of Pb, Nd and Hf, generally reflect the mantle source characteristics. The εNd–εHf relationship and trace element abundance ratios indicated that the LREE-depleted samples were mostly scraped off the subducting South China Sea floor, reflecting the volumetric dominance of N-MORB on ocean floors. The overriding Philippine Sea Plate contributed both N-MORB and E-MORB to the accretionary prism. The tectonic affinities of the LREE-enriched samples, however, could not be unambiguously determined for the large geochemical variability of OIB from both subducting and overlying slabs. Based on our results, it is proposed that the tectonic affinity of the basalts in an accretionary prism can indicate the subduction polarity of the associated convergent boundary, providing a constraint for regional geology evolution.
AB - Tectonic affinities of accreted basalts provide constraints on mass transport in convergent boundaries, improving our understandings on the evolution of regional geology. In this study, nineteen accreted basalts from the southernmost tip of Taiwan Island, which is on the convergent boundary between the Eurasian and Philippine Sea Plates, were analyzed for element concentrations as well as Sr, Nd, Hf, and Pb isotope ratios to investigate their tectonic affinities. All the samples contain > 3% LOI, reflecting post-magmatic alteration. LOI and Nb variation diagrams together with comparisons to oceanic basalt compositions indicated that the concentrations of most major elements and Rb, Sr, and Ba were modified by post-magmatic processes to varying extents, while P2O5, REE and HFSE remained immobile. Although some samples show Pb loss, most samples have Pb concentrations not affected by post-magmatic processes. Isotope ratios of Pb, Nd and Hf, generally reflect the mantle source characteristics. The εNd–εHf relationship and trace element abundance ratios indicated that the LREE-depleted samples were mostly scraped off the subducting South China Sea floor, reflecting the volumetric dominance of N-MORB on ocean floors. The overriding Philippine Sea Plate contributed both N-MORB and E-MORB to the accretionary prism. The tectonic affinities of the LREE-enriched samples, however, could not be unambiguously determined for the large geochemical variability of OIB from both subducting and overlying slabs. Based on our results, it is proposed that the tectonic affinity of the basalts in an accretionary prism can indicate the subduction polarity of the associated convergent boundary, providing a constraint for regional geology evolution.
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U2 - 10.1016/j.jseaes.2018.02.015
DO - 10.1016/j.jseaes.2018.02.015
M3 - Article
AN - SCOPUS:85043454430
VL - 158
SP - 253
EP - 265
JO - Journal of Asian Earth Sciences
JF - Journal of Asian Earth Sciences
SN - 1367-9120
ER -