古俯冲带 meaning in English
palaeo-subduction zone
Examples
- The southern hainan mafic dykes are strongly enriched in lile with high nb / ta ratios , indicating a magma source reconstructed by silicic - melt through partial melting of ancient subducted slides . however , the northern hainan mafic dykes with chondritic nb / ta ratio should be derived from the fiuid - metasomatized mantle related to ancient subduction zone
琼南基性岩脉强烈富k _ 2o等lile和具有较高nb ta比值，其地幔源区应受到了古俯冲板片部分熔融形成的硅质熔体的改造；而琼中基性岩脉的nb ta比值接近于球粒陨石和morb值，应为古俯冲带含水流体交代的地幔源区的产物。 - The pges abundance patterns of residual mantle rock with a peleo - subduction background is characterized by pd , pt depletion and ir , ru relatively enrichment , while the basalt and basic dyke by the processing of partial melt in the same background take an opposite feature of pd , pt enrichment and ir , ru depletion . the existence of fluid in the subduction zone increases the degree of partial melt on the one hand , and on the other , activates the activity of pd , pt compare to ir , ru , and thus reduces the pd ir and pt ru in residual mantle rock . the pges patterns for basalt and basic dyke from two carboniferous volcano zones to south qoltag and north turpan - hami basin , xinjing uigur autonomous region , take a shape of gentle positive inclined curve with lower pt and pd differentiation and lower pges . all these features are obviously different from that of basic dyke and basalt from typical ophiolite and therefore the author believe that their fluid - rich paleo - subduction zone environment can be ruled out
古俯冲带背景下的残余地幔岩的pges配分以pd , pt明显亏损和ir , ru相对富集为特征，而部分熔融产物的玄武岩和基性岩脉则呈现相反的ir , ru明显亏损和pd , pt相对富集特征。俯冲带中流体的参与一方面增加了部分熔融程度，有利于pd , pt从原始地幔进入熔融相另一方面，流体的作用使得pd , pt相对于ir , ru迁移活动性效率提高，造成地幔岩中