Ocean island basalts (OIB) are one kind of ocean basalts, which are distributed far away from subduction zone in the form of islands. Its typical geochemical characteristics are as follows: (1) Sr, Nd, Pb and Hf isotopes are enriched in radiogenic isotope composition relative to normal MORB (EM1, EM2 and HIMU end elements can be distinguished); (2) In terms of trace element composition, compared with HREE, LILE and LREE are enriched, HFSE is not depleted or even enriched, and Pb is depleted. The typical origin of oceanic island basalt is Hawaii. The traditional model believes that ocean island basalt is the product of hot spot action, and then speculates that its source area is the mantle plume from the core mantle boundary, but so far it has not been verified in geochemistry. In addition to Hawaii, there are many ocean island basalts (including Iceland) with the above geochemical characteristics in the ocean, but there is a great debate about whether their mantle source region is the deep lower mantle or the shallow upper mantle. Geochemical studies of oceanic island basalts provide important constraints for understanding the formation and evolution of the mantle, its internal structure and chemical geodynamics. The isotopic composition changes of oceanic island basalts can be described by a limited number of mantle end elements, such as EM1, EM2 and HIMU. However, the coupling relationship between these end elements and major and trace elements is not unique, leading to problems in using these end elements to interpret the nature of the mantle source region. Ocean island basalt is generally regarded as the product of intraplate magmatism, but more and more studies have found that it contains information about the circulation of crustal materials, indicating that it is also the product of plate subduction. Crustal materials enter the deep mantle through subduction and delamination, which plays an important role in the formation of mantle heterogeneity; However, how these materials are extracted by partial melting, such as the existence of olivine poor rocks in the mantle source area of ocean island basalt, is still a hot topic of debate. It has become the focus of debate whether the source area of the oceanic island basalt mantle is the lower mantle primitive material or the geochemical relatively enriched mantle metasomatic rock produced by recycling crustal materials of different components into the upper mantle.
