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现有资料表明,早期大陆形成于上地幔的下陷作用,并在27—30亿年间迅速增长。Nd同位素研究结果证明,代表早期大陆增长的英云闪长岩主要起源于古老亏损地幔。然而微量元素及氧同位素资料却表明这种英云闪长岩应起源于富集型源层。若在地球早期的去气作用期间(≥44亿年)地幔分异成亏损地幔库(DMR)和富集地幔库(EMR),那么上述矛盾便可得到解释。EMR块体可循环进入地幔,EMR—DMR混合物可做为形成太古宙玄武岩的源层,这种玄武岩在沉降过程中由于深海蚀变、交代作用,或通过其它地幔作用过程。使不相容元素富集,然后遭受湿条件下的部分熔融产生英云闪长岩岩浆。在英云闪长岩产生前不到150Ma时间里富集作用便已发生。高原玄武岩堆积在封闭洼地里并随着冷却作用的进行地热进入榴辉岩稳定区玄武岩高原上形成离密度的榴辉岩根,并在27—30亿年前把玄武岩拉回地幔,导致英云长岩快速形成,从而也导致大陆迅速增长。
Available data show that the Early Continental formed in the upper mantle of the subsidence and rapid growth in 27-30 billion years. Nd isotope studies have shown that the diorites, which represent the early continental growth, originated mainly from the ancient depleted mantle. However, the trace elements and oxygen isotope data show that this type of diorite should originate from the enriched source. The above contradiction can be explained if the mantle differentiates between the depleted mantle (DMR) and the enriched mantle (EMR) during the early deglaciation (≥44 billion years) of the earth. EMR blocks can circulate into the mantle, and the EMR-DMR mixture can be used as a source for the formation of Archean basalts that have been replaced by deep-sea alteration, metasomatism or other mantle processes during the subsidence. Enriched in incompatible elements, and then subjected to partial melting under wet conditions to produce magmatic diorites. Enrichment has taken place in less than 150 Ma prior to the occurrence of the British-type diorites. Plateau basalts accumulate in the enclosed depressions and geothermal heat moves into the basaltic plateaus of the eclogite stability zone to form eclogite eclogites at an intact depression and pull basalts back into the mantle from 27 to 30 billion years ago, Rapid rock formation, which also led to the rapid growth of the mainland.