Fig. 3
From: Development of a quartz-based geothermometer for biogenic chert
(a) Field occurrence of the Upper Triassic bedded biogenic chert in the Mino belt in Chubu province, Japan (sample No. 10). Refer to Fig. 3e and Table 1 for locality details. (b) Optical photomicrograph (obtained in plane polarized light) of the Upper Triassic biogenic chert including numerous radiolarian tests (white spots in the picture). Plane polarized light. (c) Backscattered scanning electron image of a bedded metachert sample obtained from the Ryoke belt in Chubu province, Japan. (d) Optical photomicrograph (obtained in cross-polarized light) of a bedded metachert sample composed of crystalline quartz obtained from the Ryoke belt in Chubu province, Japan. (e) Satellite image of the locality around sample No. 10. The image was taken from Google Earth Pro (https://www.google.com/permissions/geoguidelines/?hl=ja). Following the oceanic plate stratigraphy, the chert layers are overlain by siliceous shale and clastic rocks. Ch.: bedded radiolarian chert, Ssh.: siliceous shale, Cl.: clastic rocks, Loc.: locality, Rv: river. (f) Field observation of the alternating layers of sandstone and mudstone beds overlying the radiolarian chert beds. The locality is shown in Fig. 3e.
