Mantle heterogeneity beneath Changbaishan volcanic province: evidence from geochemical study on trace elements and isotopes

作者：Sui J L^*; Fan Q C; Liu J Q; Guo Z F

来源：Acta Petrologica Sinica, 2007, 23(6): 1512-1520.

• changbaishan volcanic province
• mantle heterogeneity
• fractionation of Nb/Ta

The complexity of continental volcanism is a global phenomenon, which has confused the geologists for a long time. The Changbaishan Volcanic Province ( CVP), located at the active margin of the eastern Asia Plate with large scale volcanic and tectonic activity, provides a natural laboratory for exploring continental volcanisms and their mantle sources. Tianchi Volcanic field (TV) and Longgang Volcanic field ( LV) are two important parts of the CVP. Comparison on petrology and geochemistry indicates that volcanic rocks from the TV and the LV came from different mantle sources, the LV came from primary mantle source, while the TV came from hybrid mantle sources of primary mantle and enriched mantle. Distance between LV and TVP is only about 40km, so the mantle source of CVP has small scale heterogeneity. Volcanic rocks of TV have strong negative Ta abnormity and significant fractionation of Nb/Ta ( Nb/Ta = 10 similar to 50, some basalts even over 100). This fact, combined with the Sr, Nd and Pb isotopic data, indicates that the TV mantle source experienced reactions between melts from partial melting of the subducted slab and minor minerals, such as rutile, while LV has no geochemical signals of such contamination.

• 出版日期2007-6
• 单位中国科学院地质与地球物理研究所; 中国地震局; 中国科学院地质与地球物理研究所兰州油气资源研究中心