The knowledge of core material of polymetallic nodules is of great importance for clarification of the distribution and origin of nodules in ocean. Based on dissection of about 178 pieces of samples of polymetallic nodules obtained from the East Pacific Basin by investigation ship “HAIYANG 4”of MGMR among which 53 pieces are basaltnuclei in composition, accounting for 298%, this paper comprehensively studied and analysed the features of these basaltunclei of nodules, including lithology , petrochemsitry ,mineral constituents, traceelement geochemistry and isotope chronostratigraphy,etc. The authors come to a conclusion that the basaltnuclei of nodules belong to ocean island tholeiite or alkalibasalt. There are of calcalkaline series and alkali series, which include olivinetholeiite, and alkali basalt, and they were mainly formed in the Tertiary. In the light of studies of the origin of basaltnuclei of nodules, and analysis of the relationship between the basaltnuclei and the distribution of ploymetallic nodules, the authors pointed out that basaltnuclei of nodules are derived from seamount basalt in the study area. It is found that seamount basalt mainly effected and controlled the formation and distribution of polymetallic nodules, which provied enormous nuclei.
Geological Journal of China Universities