Ⅰ. INTRODUCTIONResearches on lead isotopes of oceanic basalts and ore lead indicate that the value of mantle has undergone considerable increase since the Archean or Proterozoic, which means that uranium got enriched...Ⅰ. INTRODUCTIONResearches on lead isotopes of oceanic basalts and ore lead indicate that the value of mantle has undergone considerable increase since the Archean or Proterozoic, which means that uranium got enriched in the crust-mantle system in comparison with lead and that lead or uranium mass is in disequilibrium. Some researchers think that lead as a sulphophile element went down into the core resulting展开更多
The Pb-Sr-Nd isotopic data of Cenozoic volcanic rocks from the continent of China show that there exist three main end members of the mantle, which are the enriched mantle of Wudalianchi in Northeast China, the deplet...The Pb-Sr-Nd isotopic data of Cenozoic volcanic rocks from the continent of China show that there exist three main end members of the mantle, which are the enriched mantle of Wudalianchi in Northeast China, the depleted mantle in South China and the recycling mantle of Yunnan in southwestern China. A11 the data can well fit a curved surface of three-component mixing in Pb-Sr-Nd isotopic space. Seven major end members in the global mantle can be identified. Based on the intersection line between two curved surfaces of three-component mixing in the continent of China and the ocean, the Pb-Sr-Nd isotopic ratios in the primatire mantle can be calculated. In order to explain the genesis of seven end members of the mantle, four-and three-system recycling models were used. The theoretical results are well comparative with the isotopic distribution observed in global Cenozoic volcahics, and can provide useful constraints on the process of the geochemical evolution in the crust-mantle system.展开更多
文摘Ⅰ. INTRODUCTIONResearches on lead isotopes of oceanic basalts and ore lead indicate that the value of mantle has undergone considerable increase since the Archean or Proterozoic, which means that uranium got enriched in the crust-mantle system in comparison with lead and that lead or uranium mass is in disequilibrium. Some researchers think that lead as a sulphophile element went down into the core resulting
基金Project supported by the National Natural Science Foundstion of China.
文摘The Pb-Sr-Nd isotopic data of Cenozoic volcanic rocks from the continent of China show that there exist three main end members of the mantle, which are the enriched mantle of Wudalianchi in Northeast China, the depleted mantle in South China and the recycling mantle of Yunnan in southwestern China. A11 the data can well fit a curved surface of three-component mixing in Pb-Sr-Nd isotopic space. Seven major end members in the global mantle can be identified. Based on the intersection line between two curved surfaces of three-component mixing in the continent of China and the ocean, the Pb-Sr-Nd isotopic ratios in the primatire mantle can be calculated. In order to explain the genesis of seven end members of the mantle, four-and three-system recycling models were used. The theoretical results are well comparative with the isotopic distribution observed in global Cenozoic volcahics, and can provide useful constraints on the process of the geochemical evolution in the crust-mantle system.
