Correlation of the Eocene subduction complex in Kyushu-Ryukyu Arc.

通过沉积变形面分析，研究了九州-琉球弧始新世俯冲杂岩构造-沉积演化的横向变化。环境，以及微化石的年龄。九州的Hyuga群。中始新世晚期至渐新世早期，可以重建为一个典型的俯冲杂岩，它由一个充分发育的增积棱柱、海沟斜坡沉积和弧前盆地层序组成。各单元均为同生异位相。俯冲杂岩的发育可能表明了一个正交的俯冲过程。中始新世晚期Aamami-Oshima的Wano组和冲绳岛的Kayo组分别代表堆积在斜坡-内扇-中扇和大型水道阶地中的深海扇序列。这两个建造都显示出复杂的褶皱构造，但排除了任何增量变形。九州和琉球弧前构造格局的差异可能反映了始新世菲律宾海板块沿原琉球弧聚合角的区域性变化。

Lateral change of tectono-sedimentary evolution of the Eocene subduction complexes of Kyuushu and Ryukyu Arc were examined from the analysis of sedimentary and deformation faceis. environments, and ages in terms of microfossils.The Hyuga group in Kyushu. late Middle Eocene to Early Oligoceneages, can be reconstructed as a typical subduction complex, that consists of a fully grown accretionary prism developed by both underplanting and offscraping processes, a trench slope deposits, and a forearc basin sequence. All of the units are of the contemporaneous hetrotopic facies. Development of the subduction complex may indicate a orthogonal sub-duction process. The wano Formation in Amami-Oshima and the Kayo Formation in Okinawa Island, late Middle Eocene age, represent deep-sea fan sequences accumulated in a slope- inner to middle fans, and in a large scale channel terrace, respectively. Both of the formations show a complicated fold structures, but exclude any accretionary deformations. They can be attributed to a consumption forearc, because of presence of the Creraceous basement beneath the forearc basins.The difference in framework of forearc between Kyushu and Ryu may suggest the regional variety of convergent angle of the subducting Philippine Sea Plate along the proto-Ryu arc of Eocene time.