Two kinds of basalts with different chemical compositions were obtained in the Sanshui Basin,they share the same eruption period. Although they have significant differences in major and trace element concentrations,th...Two kinds of basalts with different chemical compositions were obtained in the Sanshui Basin,they share the same eruption period. Although they have significant differences in major and trace element concentrations,their isotopic ratios suggest a similar magma source. Based on mineral geochemical analysis,orthopyroxene with reaction rim and zoned clinopyroxene are observed in Zidong(ZD)basalts,but not found in Wangjiegang(WJG) basalts. Linear scanning of these minerals suggests compositional variation between within-plate tholeiite and within-plate alkali-basalt. Presence of a doublelayer magma chamber under the Sanshui Basin,and occurrence of magma mixing between upper and lower chambers is proposed. This magma mixing leads to different chemical composition and mineral constitution of two kinds of basalts,as well as reaction rim and compositional variation of minerals in ZD basalts.展开更多
基金financial supported by the National Natural Science Foundation of China (Nos. 41276047, 41030853, 41572207, 41440041)the Special and Frontier Foundation for the Twelve Five Plan of the China Ocean Mineral Resources Research and Development Association (No. DY125-22-QY-21)
文摘Two kinds of basalts with different chemical compositions were obtained in the Sanshui Basin,they share the same eruption period. Although they have significant differences in major and trace element concentrations,their isotopic ratios suggest a similar magma source. Based on mineral geochemical analysis,orthopyroxene with reaction rim and zoned clinopyroxene are observed in Zidong(ZD)basalts,but not found in Wangjiegang(WJG) basalts. Linear scanning of these minerals suggests compositional variation between within-plate tholeiite and within-plate alkali-basalt. Presence of a doublelayer magma chamber under the Sanshui Basin,and occurrence of magma mixing between upper and lower chambers is proposed. This magma mixing leads to different chemical composition and mineral constitution of two kinds of basalts,as well as reaction rim and compositional variation of minerals in ZD basalts.
