Relationships between the major geologic structures and active fault system in the Mino-Tanba Belt, central Japan.

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The distinct strike-swings of the Jurassic accretionary are studied in the Neo Syntaxis area along the Yanagase active fault and its northern extention in the northern Shiga and southern Fukui Prefectures. The strike-swings around there were formed as kink-like (megakink) or chevron folds with N-S trending hinge surface and verticaly-plunging hinge axis. In the northern part, the strike swings are composed of smaller-scale folds with vertical axes, and in the southern part the Yanagase Fault occupies along the hinge surface of the tightly closed strike-swing about 10 km in half-wavelength. Hence, the origin of the Yanagase fault was intimately related to the formation of the sudden strike-change of the strata of the Mino-Tanba BeltThe basement structures, tectonic topographies and fault-rock fabrics along the Rokko Rault system and Mitoke-Tonoda fault in the Tanba Belt, and the Iida-Matsukawa and Sakaitoge-Kamiya fault in the Mino and Ryoke Belt are precisely studied. As the results, it has clarified that these structural elements are very important not only to solve the history of active faulting but also to reveal the physical conditions and displacement sense of faulting.Standardization of illite crystallinity data were checked by using the Crystallinity Index Standard (CIS) sample to evaluate the thermal history of the accretionary complex. The results suggest that the CIS standardization is a fundamental procedure for comparison of the IC data measured by different laboratories.The structural analyses of the Mesozoic Torlesse Terrane in South Island, New Zealand, suggest that the pre-existing accretion-related structures were strongly modified by the Neogene disturbances. The features of the secondary deformations are comparable to those of the Mino-Tanba Belts, suggesting that the strike-swings about the moderately to vertically plunging rotation axes are fundamental structural process of the accretionary sediment-dominated terrane.