Olivine is one of the earliest crystallized minerals in the process of magma crystallization evolution. Its chemical composition is not only controlled by the parent magma composition, but also influenced by the crystallization differentiation of magma, part melting degree, temperature, pressure, magmatic mixing, the reaction between olivine and residual magma. The basic understanding is that the main composition of olivine is mainly related to the source area, fractional crystallization and magma evolution degree, which is important evidence to figure out whether the basalt is from original magma or not. According to the value of Fo we can rebuild the magma is rich in Mg or Fe. Few previous researchers believed that olivine was related to the tectonic environment. Based on the study of main elements of olivine in global mid-ocean ridge basalt（MORB）, ocean island basalt（OIB）and island arc basalt（IAB）, we find that olivine can be used to discriminate the tectonic background, especially the OIB has much difference with MORB and IAB in many elements. MORB and OIB can be distinguished by Ni, P, Fo, K, Mn, and OIB and IAB also can be distinguished in some cases, however, it is difficult to distinguish the olivine in MORB and IAB, which needs further study. Global data research shows that Ni-rich of olivine in OIB is a very important phenomenon, this paper believes that MORB and IAB derive from the depleted upper mantle, so value of Fo is high; OIB derives from the enriched lower mantle, and Fe-Ni core may have significant effect on its chemistry composition, which leads to olivine is poor in Fo and rich in Ni in OIB.
Li Yuqiong Du Xueliang Jin Weijun Du Jun Zhang Qi Wang Jinrong Ma Zhen. A comparative study of olivine in mid-ocean ridge basalt（MORB）,ocean island basalt （OIB） and island arc basalt （IAB）[J]. Chinese Journal of Geology, 2018, 53(4): 1228-1239.