Study on twilled structure-Superimposed deformation in the Shimanto Belt of the Ryukyu Islands-

褶皱构造是指由两个不同方向的断层所围成的块体构造，每个块体的层理或岩性方向分别代表不同的方向，如褶皱布。该构造位于冲绳岛和十敷岛，晚渐新世时形成的北东-南西向的褶皱和断裂系统，与晚第四纪的北西-南东向的断裂叠加，形成了褶皱构造。以嘉代组砂岩中的石英颗粒为应变标志，进行了三维应变分析。但结果并不令人满意，因为没有显示应变场中的叠加变形，而只显示了凝固过程中的破裂变形。

Twilled structure signifies a block structure bounded by faults of two different directions and the orientation of bedding or schistosity of each block represents different direction respectively such as twilled cloth. The structure is discovered in the Okinawa-jima and Tokasiki-jima.The fold and fault system of NE-SW direction had been accomplished in the late oligocene time has been superimposed by the faulting of NW-SE direction in the late quaternary producing the twilled structure. They have also dome and basin structure in each block suggesting a superimposed deformation.Three dimensional strain analysis have been carried out using quartz gains of the sandstones from the Kayo Formation as strain marker. The result is however, not satisfied because the superimposed deformation in the strain field is not revealed but a seak deformation during the soldification is only shown.