Terrane analysis of Mesozoic complexes in East Asia

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According to the exchange program between Nanjing University and Nagoya University, we have carried out a special cooperative work on the geological structure of the Asian continent. This work suggests that one of the key-terranes in East Asia is the Nadanhada terrane of northeast China, and the other is a terrane in the Qinling Belt. On the basis of these investigations, we continued our studies in this project on (1) the Nadanhada terrane, and on (2) the western part of the Qinling Belt. (A) S. Mizutani, J. A. Shao and Q. Yang have performed the geological and micropaleontological investigations of the Triassic-Jurassic radiolarian rocks of the Nadanhada terrane, and disclosed that i) the radiolarians are commonly found in a formation straddling on the boundary between Triassic and Jurassic age, ii) the radiolarian assemblages belonging to the Triassic and the Jurassic are very similar to each other between China and Japan, and iii) in spite of these similarities, the lithological nature of the host-rock from which the fossils have been extracted is somewhat different ; the rock is bedded chert in Japan, whereas it is siliceous shale in China. (B) S. Mizutani, T. Ishikawa, I. Hattori and H. Nagai together with the Chinese geologists (Q. L. Zhang and Z. F. Sun) visited the western part of the Qinling Belt. The Triassic Feng-Hui terrane composed of epiclastic complex is recognized there ; in addition, a Devonian coarseclastic stratigraphic terrane may well be distinguished. Presence of these terranes implies that the Qinling Belt itself is an elongated collage zone developed in a suture between North China Block and South China Block.