At present, MORB is the most detailed basanitoid, can be divided into two categories,N-MORB and E-MORB. It is generally considered that both N-MORB and OIB are independent end-members from depleted and enriched mantle-derived rocks, while E-MORB is the result of mixing N-MORB with OIB. The main causes of E-MORB enrichment are not because of the ridge depth, the ridge expansion rate, the partial melting degree and pressure of the source region, The results show that the E-MORB has the complex cause. The influence of pressure and partial melting degree on basalt composition is much less than that of mantle heterogeneity.It is speculated that the E-MORB may have two main forms of formation: One is partially melted by a slightly enriched mantle; another is formed by mixing N-MORB with OIB. The frequency histogram of trace elements in basalts shows that N-MORB basically maintains the
characteristics from the depleted mantle source region. The trace elements histograph in basalts shows that N-MORB basically maintains the characteristics from the depleted mantle source area, but OIB is more or less affected by the addition of foreign material or mixed with N-MORB; E-MORB is the product of N-MORB affected by OIB. OIB and E-MORB, only the impact and the degree of mixing is different. It seems to have no essential difference. OIB enrichment LILE, may inherit the characteristics from the source area. OIB enrichment LILE,may have inherited from the source area characteristics, including deeply enriched mantle,circulating ancient oceanic crust, recirculating continental crust, continental lithosphere mantle, LVZ melt layer or early metasomatic veins etc; may also have the impact of the addition of foreign material, including in varying degrees of mixing with N-MORB. The distribution of 87Sr/86Sr and 143Nd/144Nd isotopic frequencies of the three basal basalts is consistent with the previous conclusion, but the 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb isotopic frequency
distributions show that OIB has more complex characteristics.
An Yi Yang Jing Chen Wanfeng Wang Jinrong Zhang Qi Pan Zhenjie Jiao Shoutao . The revelation of big data：Differences between N?MORB，E-MORB and OIB and their possible causes[J]. Chinese Journal of Geology, 2017, 52(3): 727-742.