Nappe-bounding thrust faults in the Paleozoic-Mesozoic accretionary
orogen in the Inner Zone of southwestern Japan

Akira Ishiwatari*, Tatsuki Tsujimori*, Yasutaka Hayasaka**,
Takashi Sugimoto** and Hiroaki Ishiga***

*Department of Earth Sciences, Faculty of Science, Kanazawa University
**Dept. of Earth and Planetary Sci., Fac. of Sci., Hiroshima University
***Department of Geoscience, Shimane University


This article was published in the Journal of the Geological Society of Japan, Vol. 105, No. 2, pp. III-IV (1999).

[English Top Page]


Fig. 1. Localities of thrust outcrops in SW JapanFig. 1. Nappe structure of the Inner Zone of southwestern Japan. From structural top to bottom; Ok: Oki terrane (Paleozoic and older gneisses. Western extension of the Hida terrane). Oe: Oeyama ophiolite (early Paleozoic or older), Rn: Sangun-Renge nappe (middle Paleozoic high-P schist), Ak: Akiyoshi nappe (Permo-Carboniferous pillow lava, chert, limestone and clastic rocks), Ma(YK): Maizuru nappe with late Paleozoic or older Yakuno ophiolite (Yk) and its Permo-Triassic sedimentary cover, UT: Ultra-Tamba nappe (Permian chert and clastic rocks), Sg: Sangun-Suo nappe (Early Mesozoic high-P schist after Late Paleozoic-Early Mesozoic chert and clastic rocks), M-T: Mino-Tamba nappes (Jurassic clastic rocks with chert, limestone and pillow lava of Carboniferous to Triassic ages). Photographed outcrops are indicated in figure numbers.

Fig. 2. Wakasa outcrop B/W photo.Fig. 2. Thrust fault between pelitic schist of Renge nappe and the overlying serpentinized peridotite of the Oeyama ophiolite (Wakasa area, 1 km northwest of Shitani, Hatto Town, Tottori Prefecture).


Fig. 3. Niimi outcrop photoFig. 4. Niimi geologic map

Fig. 3. (left) Thrust fault between limestone of Akiyoshi nappe and the overlying serpentinite of Oeyama ophiolite (see Fig. 4 for locality).

Fig. 4. (right) Thrust fault between Akiyoshi nappe and the overlying Oeyama ophiolite. The outcrop shown in Fig. 3 is indicated by a red circle (Kawamoto Dam, Niimi City. Okayama Prefecture. After Hayasaka et al. 1995).

Fig. 5. Oya outcrop photo

 

Fig. 5. (left) Thrust fault between basaltic rocks of Yakuno ophiolite and the overlying serpentinite of Oeyama ophiolite (Fig. 6).

Fig. 6. (right) Thrust fault between Oeyama ophiolite and Yakuno ophiolite. The outcrop shown in Fig. 5 is indicated by a red circle (2 km N of Ikada, Oya Town, Hyogo Pref. After Ishiwatari and Hayasaka, 1992)

Fig. 7. Wada outcrop photoFig. 7. Thrust fault between clastic rocks of Ultra-Tamba nappe and the overlying serpentinite of Yakuno ophiolite (Wada, Takahama Town, Fukui Pref.)


Fig. 8. Obama outcrop photoFig. 9. Aogaki outcrop photo

Fig. 8. (left) Thrust fault between muddy melange (diamictite) of upper Tamba nappe and the overlying sandstone of Ultra-Tamba nappe (Katae-hana, Obama City, Fukui Pref.).

Fig. 9. (right) Thrust fault between mudstone of upper Tamba nappe and the overlying sandstone of Ultra-Tamba nappe (0.5 km south of Anaura Pass, Aogaki Town, Hyogo Pref.).


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1999/04/05 established 2001/11/24 English version 2001/11/24 renewed