Mantle Potential Temperature Estimates of Basalt from the East Taiwan Ophiolite

• Published in: TAO : Terrestrial, atmospheric, and oceanic sciences Vol. 27; no. 6; pp. 853 - 863
• Main Authors: Shellnutt, J. Gregory, Hsieh, Robert B.-J.
• Format: Journal Article
• Language: English
• Published: Taiwan 中華民國地球科學學會 01.12.2016; Chinese Geoscience Union (Taiwan); Springer
• Subjects: Basalt; Composition; Estimates; Lava; Mantle; Mantle plumes; Mid-ocean ridges; Oceans; Ophiolites; Pliocene; Potential temperature; Rock; Rocks; Subduction; Subduction zones; Temperature effects; Taiwan; South China Sea; Mantle potential temperature; Ophiolite; Taiwan
• DOI: 10.3319/TAO.2016.05.24.01(TT)
• ISSN: 1017-0839

The East Taiwan Ophiolite (ETO) is a fragment of the eastern-most South China Sea that was accreted to the Eurasian margin during the Pliocene and is a member of the Western Pacific and Cordilleran belt ophiolite group. Ophiolites from the Western Pacific and Cordilleran belt are typically subduction-related (i.e., supra-subduction or volcanic-arc) but the ETO is compositionally, isotopically and mineralogically similar to subduction-unrelated ophiolites. The primary melt compositions of ETO basaltic rocks were calculated and range from high-Mg basalt to picrite (i.e., MgO = 10 to 14 wt%). The mantle potential temperature (T_P) estimates are within the range of ambient mantle (1300 - 1400°C) and other mid-ocean ridge ophiolites (i.e., Macquarie Island and Masirah) indicating that it is consistent with a mid-ocean ridge setting. Mantle potential temperature estimates for rocks from a mantle-plume-type ophiolite (i.e., 1620 - 1630°C) are anomalously high whereas rocks from supra-subduction zone ophiolites show a wider range that extends from ambient (i.e., Troodos and Semail) T_P to very high (i.e., Betts Cove and Bay of Islands) T_P.