关键词: 大火成岩省, 地幔柱, 苦橄岩, 岩石圈, 核-幔边界, 热点

Abstract:

It has long been debated around the mantle plume since Morgan(1971)proposed mantle plume that was used to explain the trail of volcanoes. Large igneous provinces(LIPs)are characterized by large volume of magmas during short interval, which is generally considered to be related to mantle plume. The main reason is that the hypothesis of mantle plume is supported by many geologic evidences:(1)large volume mantle-derived magmas;(2)>500 m uplift before magmatism;(3)high-temperature picrites or komatiites;(4)hotspot trail leading LIPs;(5)melting of mantle without volatiles or decompressing;(6)high ³He/⁴He ratio. However, not all LIPs are consistent with the all above predictions. Alternately, some of the above predictions can also be reached by other models, such as edge-drive convection, large scale of delamination of lithosphere, rift-related decompression melt and meteorite impact. It is noted that, until now, no models are consistent with the geologic evidences from LIPs. Comparably, many evidences from LIPs account for the prediction of plume model.

Key words: large igneous province, mantle plume, picrites, lithosphere, core-mantle boundary, hotspot