Shimanto Supergroup in the southern part of Tokushima Prefecture, SouthwestJapan

Kumon, Fujio

doi:10.5575/geosoc.87.277

Cited by 23 publications

(30 citation statements)

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“…It consists mainly of sheared dark-gray shale (herein the m elange matrix shale) containing sandstone blocks. Other lithologies in the Mugi M elange include oceanic basalt, red and varicolored hemipelagic shales, pelagic chert, and acidic tuff (Kumon, 1981;Kiminami et al, 1992;Onishi and Kimura, 1995;Ikesawa et al, 2005).…”

Section: The Mugi M Elangementioning

confidence: 99%

Complete 40Ar resetting in an ultracataclasite by reactivation of a fossil seismogenic fault along the subducting plate interface in the Mugi Mélange of the Shimanto accretionary complex, southwest Japan

Tonai

Ito

Hashimoto

et al. 2016

Journal of Structural Geology

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Section: The Mugi M Elangementioning

confidence: 99%

Complete 40Ar resetting in an ultracataclasite by reactivation of a fossil seismogenic fault along the subducting plate interface in the Mugi Mélange of the Shimanto accretionary complex, southwest Japan

Tonai

Ito

Hashimoto

et al. 2016

Journal of Structural Geology

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“…The Hiwasa Formation is mainly composed of thick‐bedded turbidite sandstones with conglomerates. Acidic volcanic clasts are predominant in the Hiwasa conglomerates, and they are mostly of rhyolite tuff and lava ( Kumon 1981). Detrital assemblage of the Hiwasa conglomerates is consistent with that of the Hiwasa sandstones.…”

Section: Discussionmentioning

confidence: 99%

Geochemical contrast between the Sanbagawa psammitic schists (Oboke unit) and the Cretaceous Shimanto sandstones in Shikoku, Southwest Japan and its geologic significance

1999

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A systematic geochemical study of sandstones from the Cretaceous Shimanto Supergroup and psammitic schists from the Oboke unit in Shikoku has been carried out in order to clarify the depositional age of the protoliths of the Oboke psammitic schists. The geochemical data, together with chronological and geologic data, led to the following conclusions. (i) It is inferred that Oboke psammitic schists are metamorphically equivalent to sandstones in the Hiwasa Formation of the Shimanto accretionary complex, deposited in a trench area during the Campanian, in eastern Shikoku. (ii) The protolith attained to maximum metamorphic conditions within 20 million years after the deposition. (iii) The accumulation of a large amount of coarse‐grained clastic sediments in the trench area induced offscraping and underplating of the sediments in the subduction zone, forming the Hiwasa Formation and Oboke unit, respectively.

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“…Furthermore, sandstone and conglomerate are well developed. The stratigraphy and detailed description of coarse clastic rocks had already reported by the author (KUMON, 1981(KUMON, , 1983. In this paper, the author will discuss mainly the geologic significance of the upwardincreasing trend of rock fragments in sandstone throughout the Cretaceous sequence.…”

Section: Introductionmentioning

confidence: 99%

“…cf. kayei and Coniacian to Campanian radiolarian fossils (SUYARI et al, 1967;KUMON, 1981). The Hiwasa Formation is estimated to be Campanian to Maestrichtian in age, judging from its great thickness.…”

Section: Geologymentioning

confidence: 99%

Stratigraphic Change of the Coarse Clastic Rocks of the Shimanto Supergroup in Eastern, Shikoku, Southwest Japan

Kumon¹

1985

Formation of Active Ocean Margins

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Abstract. The Shimanto Supergroup of geosynclinal facies which ranges from Cretaceous to early Tertiary in age, is widely distributed in the outermost zone of Southwest Japan. Coeval volcanic and plutonic rocks are extensively distributed in the Inner Zone. The coarse clastic rocks mainly of sandstone occupy about a half of the Shimanto Supergroup, and a stratigraphic change of sandstone and conglomerate composition is recognized in the supergroup. The amount of rock fragments, chiefly acidic to intermediate volcanic rocks, increases upward throughout the Cretaceous sequence. Additionally, acidic tuff layers are frequently intercalated in the Late Cretaceous sequence. Conglomerates in the Late Cretaceous are very dominated by acidic volcanic rock clasts. The geosynclinal sedimentation of the Cretaceous Shimanto Supergroup proceeded with the coeval volcanism which became more active in the Late Cretaceous. The clastic sediments were supplied mainly from the sites of the volcanism. The volcanism corresponds to the Cretaceous volcanic activity in the Inner Zone of Southwest Japan. The Cretaceous Shimanto Supergroup may represent a typical forearc sedimentation in an arc-trench system.

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Shimanto Supergroup in the southern part of Tokushima Prefecture, SouthwestJapan

Cited by 23 publications

References 0 publications

Complete 40Ar resetting in an ultracataclasite by reactivation of a fossil seismogenic fault along the subducting plate interface in the Mugi Mélange of the Shimanto accretionary complex, southwest Japan

Complete 40Ar resetting in an ultracataclasite by reactivation of a fossil seismogenic fault along the subducting plate interface in the Mugi Mélange of the Shimanto accretionary complex, southwest Japan

Geochemical contrast between the Sanbagawa psammitic schists (Oboke unit) and the Cretaceous Shimanto sandstones in Shikoku, Southwest Japan and its geologic significance

Stratigraphic Change of the Coarse Clastic Rocks of the Shimanto Supergroup in Eastern, Shikoku, Southwest Japan

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