Reconstruction of chert-clastic sequence of the Ashio Terrane in the Kuzu area, central Japan.

Kamata, Yoshihito

doi:10.5575/geosoc.103.343

Cited by 19 publications

(23 citation statements)

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“…The vegetation in both watersheds is composed of Japanese cedar and cypress plantations. Bedrock in the sandstone-shale watershed is alternating beds of sandstone and shale; the chert watershed is underlain with bedded chert (Fujimoto, 1961;Kamata, 1997). Both areas have some volcanic deposits, including pumice and ash, on hillslopes, with a maximum thickness of 1Ð5 m.…”

Section: Site Descriptionmentioning

confidence: 99%

Coupling of runoff processes and sediment transport in mountainous watersheds underlain by different sedimentary rocks

Hattanji

Onda

2004

Hydrological Processes

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Abstract:Runoff and sediment transport were observed in two mountainous watersheds with different lithologies. One watershed is underlain by chert and the other by sandstone and shale. The chert watershed consists of bedrock cliffs and shallow regolith (0-2 m), whereas the sandstone-shale watershed is covered with a deeper regolith (1-5 m). In the sandstone-shale watershed, a large spring located in the channel head contributed to storm runoff. Tensiometric response in regolith above the spring showed negative pressure head throughout storm runoff, thus implying that the subsurface flow in bedrock predominated even during storm runoff. In the chert watershed, the runoff coefficient was larger than in the sandstone-shale watershed. Tensiometric response in regolith showed positive pressure head during storm runoff, indicating generation of rapid subsurface stormflow. Concentration of subsurface flow from side slopes increased peak streamflow in the downstream direction. In these two watersheds, different subsurface flowpaths, including bedrock fractures, facilitated different modes of sediment transport. Groundwater outflow at the spring caused seepage erosion in the sandstone-shale watershed, whereas peak streamflow transported bedload supplied by rockfall in the chert watershed.

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Section: Site Descriptionmentioning

confidence: 99%

Coupling of runoff processes and sediment transport in mountainous watersheds underlain by different sedimentary rocks

Hattanji

Onda

2004

Hydrological Processes

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“…The chert area is underlain by Triassic bedded chert, and the sandstone area is underlain by alternating beds of Jurassic sandstone and shale. Both bedrock types have a strike in the N-S direction and an almost vertical dip (Aono, 1985;Kamata, 1997). The elevation (180-340 m), annual rainfall (~1400 mm), and average monthly temperature (2-25°C) are similar for the two areas.…”

Section: Geomorphic and Geologic Settings Of The Study Areasmentioning

confidence: 93%

Hydrogeomorphic Effects of Basin Lithology on Development of Channel Steps in First-Order Basins of the Ashio Mountains, Japan

et al. 2012

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This study focuses on lithological contrasts of headmost channel morphology of two mountainous areas underlain by chert or sandstone. The areas have contrasting runoff processes: subsurface storm flow predominates in the chert area, whereas groundwater flow recharges stable stream flow in the sandstone area. Manual field measurements from 84 sections of first-order streams revealed that channel steps develop along 26% of all sections in the chert area, while only along one section (3%) in the sandstone area. High-resolution analysis of long profiles using terrestrial laser scanning detected a weaker pattern of channel steps in a colluvial reach of the sandstone basin. The contrast in runoff processes, as well as grain-size distributions of weathering products between the two areas, influences dissimilar bed-load transport regimes and promotes spatial variations in channel profiles between headwater streams. These contrasting hydro-geomorphic processes affect channel-step morphology, indicating that lithology plays a key role in the formation of channel steps and in variations between headwater streams. [

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“…The occurrences of microfossils such as radiolaria and conodont have been reported in this area since the 1960s (e.g. Hayashi, 1963Hayashi, , 1968Koike et al, 1971;Hayashi and Hasegawa, 1981;Aono, 1985;Kamata, 1996Kamata, , 1997Takayanagi et al, 2001;Ito, 2019Ito, , 2020. et al, 1991; Geological Survey of Japan, AIST, 2018).…”

Section: Geologic Settingmentioning

confidence: 99%

Radiolarian age of Triassic striped chert within the Jurassic accretionary complex of the Ashio terrane in the Ashikaga area, Tochigi Prefecture, central Japan

Ito

2020

Bull. Geol. Surv. Japan

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A striped structure within a single chert bed has been observed in the Tamba-Mino and Ashio terranes, Jurassic accretionary complexes of the Inner Zone of Southwest Japan. This study reports striped chert beds in four sections of the Ashio terrane in Ashikaga and Sano cities of Tochigi Prefecture, namely, Hikoma, Oiwa, Tsukiya and Orihime sections, and their radiolarian ages, except for the Hikoma section. The striped chert comprises streaks and spacing. The streak indicates a thin part of a pin-striped structure within a chert bed and consists mainly of clay minerals. The spacings indicate a thick part between the streaks and is composed mainly of cryptocrystalline quartz. The Oiwa section, which contains numerous striped chert beds, partially corresponds to the middle Carnian-middle Norian (Upper Triassic). The Tsukiya and Orihime sections, which include a few striped chert beds, partially correspond to the middleupper Anisian (Middle Triassic) and upper Norian-lower Rhaetian (Upper Triassic), respectively.

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Reconstruction of chert-clastic sequence of the Ashio Terrane in the Kuzu area, central Japan.

Cited by 19 publications

References 0 publications

Coupling of runoff processes and sediment transport in mountainous watersheds underlain by different sedimentary rocks

Coupling of runoff processes and sediment transport in mountainous watersheds underlain by different sedimentary rocks

Hydrogeomorphic Effects of Basin Lithology on Development of Channel Steps in First-Order Basins of the Ashio Mountains, Japan

Radiolarian age of Triassic striped chert within the Jurassic accretionary complex of the Ashio terrane in the Ashikaga area, Tochigi Prefecture, central Japan

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