论文部分内容阅读
活动陆缘玄武岩(CAB)主要出现在安第斯,早先大多认为CAB大体相当于IAB,在许多判别图中,CAB基本上与IAB在一起,只是LILE富集和HFSE亏损的程度略有差别而已.本文的研究表明,尽管CAB富集LILE,但是,Nb-Ta亏损不是非常明显.在最新的采用大数据方法厘定的判别图中,CAB不同于IAB,不是落在IAB区,而是位于IAB与OIB的过渡区域.CAB中保留了很多OIB的印记,说明板块俯冲时伴随有来自地幔深部的岩浆的加入,故CAB中保留了OIB的印记.我们的研究还发现,在安第斯弧后盆地玄武岩具有OIB的印记,而非MORB的特征.本文按照大数据的思路,讨论了CAB的特征,并与IAB、BAB进行了初步的对比.研究表明,CAB明显不同于IAB,CAB兼具IAB和OIB的特征,但对其深度的认识还有待于今后进一步的研究.“,”The active continental margin arc basalt (CAB) occurred mainly in Andes,it is generally considered that CAB is same as island arc basalt (IAB) roughly and basically they are in flocks in many discrimination diagrams,but the degree of enriched LILE and depleted HFSE is different silightly.In this paper,showing that CAB is enriched in LILE,however it is not very obviously for Nb-Ta depletion.CAB is different from IAB in the latest big data discrimination diagrams,instead plotting in IAB region,CAB plots in the transition region between IAB and OIB.CAB retains lots of OIB traces,indicating that plate subduction is accompanied by the magma from the deep mantle,resulting the OIB traces in CAB.We also find that the back-arc basin basalt of the Andes arc occurs OIB traces,rather than MORB features.According to the idea of big data,this paper discusses the characteristics of CAB and compared with IAB and BAB preliminary,showing that CAB is significantly different from IAB and it has the characteristics of both IAB and OIB,but the deep understanding needs a further study in the future.