[S-CG56] ICDP Oman Drilling Project: Oman to Oceanic Lithosphere to Island Arc Formation and Beyond

[SCG56-18] Comparison of olivine crystal-fabrics between Oman ophiolite peridotites and Supra-subduction zone peridoitites

*Katsuyoshi Michibayashi¹ (1.Department of Earth and Planetary Sciences, Graduate School of Environmental Studies, Nagoya University)

Keywords:mantle, peridotite, Oman

The origin of Oman ophiolite is still in debate between the mid-ocean ridge model and the supra-subduction zone model. For the last two decades, we have collected peridotite samples from both ophiolites and the ocean floor and have shown how to quantify CPOs in Vp-Flinn diagram (Michibayashi et al., 2016 EPSL), since olivine crystallographic preferred orientations (CPOs) are key factors to identify the nature of the uppermost lithospheric mantle. In this study, we show similarities and differences of olivine CPOs between the Oman ophiolite peridotites and the others such as Yakuno ophiolites and IBM trench peridotites. The Oman ophiolite peridotites are unique to have axial[100] (AG type) along with typical (010)[100] (A type) and {0kl}[100] (D type) olivine fabrics, whereas the trench peridotites are locally characterized by (001)[100] (E type) and (010)[001] (B type) olivine fabrics.