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

Kumon, Fujio

doi:10.1007/978-94-009-4720-7_36

Cited by 6 publications

(16 citation statements)

References 14 publications

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“…Member. The process by which the volcanic rocks cover large area of the older basement rocks is known as roofing (Kumon, 1985). The above mentioned roofing process recorded in the Terasoma Formation took place in Coniacian time and corresponds to the Late Mesozoic felsic volcanism in the Inner Zone of Southwest Japan.…”

Section: Roofing Process In the Terasoma Formationmentioning

confidence: 99%

“…By the way, most of the sandstones of the Muro AS ranging in age from Middle Eocene to Early Miocene are richer in monocrystalline quartz than the Otonashigawa AS. The conglomerates of the Muro AS are dominated by both sedimentary and felsic volcanic rock clasts with subordinate amounts of granitic rocks (Kumon, 1983;Kumon et al, 2012). The above observations suggests that the unroofing progressed further entering into Middle Eocene.…”

Section: Unroofing In the Otonashigawa Accretionary Sequencementioning

confidence: 99%

“…3. Recognition of roofing and unroofing from heavy mineral features As stated previously, Kumon (1985) called the event of the covering over the hinterland by huge volcanic products How are the roofing and unroofing processes reflected in sandstone composition? 13 as roofing.…”

Section: Unroofing In the Otonashigawa Accretionary Sequencementioning

confidence: 99%

“…Capacious felsic volcanism covering a large area with thick piles of volcanic products is known as roofing (Kumon, 1985). On the other hand, continuous erosion leading to exposure of rocks buried at depth is known as unroofing (Groves, 1931;Mansfield, 1979).…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, continuous erosion leading to exposure of rocks buried at depth is known as unroofing (Groves, 1931;Mansfield, 1979). Systematic study of modal composition of sandstones in a vertical succession can provide valuable clues to unravel the roofing and unroofing events in the provenance (Mansfield, 1979;Kumon, 1983Kumon, , 1985Kusunoki and Musashino, 1989;Oyaizu and Kiminami, 2004). Such changes in the source area can be substantiated from the nature and chemical composition of the heavy minerals present in the sandstones (Chaundhri, 1972;Obayashi, 1995;Udden and Lundberg, 1998).…”

Section: Introductionmentioning

confidence: 99%

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How are the roofing and unroofing processes reflected in sandstone composition? —A case study in the Shimanto Belt, Kii Peninsula, southwestern Japan—

Bessho

2015

Jour. Sed. Soc. Japan

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1＊Multi-approach studies combining modal, heavy mineral and garnet analyses of sandstones have been carried out on the Late Cretaceous Terasoma Formation and the Palaeogene Otonashigawa Accretionary Sequence (AS) of the Shimanto Belt in the Kii Peninsula, Southwest Japan. Modal compositions of the Terasoma Formation change upward from feldspathic wacke to lithic wacke. Heavy mineral assemblages also change upward from the one rich in zircon and garnet with epidote, titanite and allanite to the one rich in euhedral zircon. The garnets from the Lower Member are mostly almandine, low and intermediate P/T types with minor high P/T type and grandite. In the Middle Member, the proportion of low P/T type increases at the expense of high P/T type and grandite garnets. These trends suggest that Coniacian violent felsic magmatism took place and their products thickly roofed the basement rocks. Modal compositions of the Haroku formation in the Otonashigawa AS change upward from lithic wacke to feldspathic arenite. The heavy mineral assemblages of the lower members are rich in zircon and garnet accompanied by allanite and greenish-brown hornblende. Sandstones of the uppermost member contain abundant epidote, allanite and titanite. The chemical compositions of detrital garnets also show a decreasing trend of the pyrope-rich almandine (intermediate P/T type garnet) and an increasing trend of spessartine-rich almandine (low P/T type garnet) from the lower to upper members. A few grandites were extracted from the uppermost horizon. These data suggest that felsic volcanic products and intermediate to high grade metamorphic rocks are the probable sources of the Otonashigawa AS. Due to the successive erosion, granitic, low P/T metamorphic rocks and calcareous metamorphic rocks were exposed to the surface. Roofing and unroofing processes are especially suggested by changes of the proportion of euhedral zircon, allanite, spessartine-rich almandine garnet (L), high P/T garnet and grandite garnet.

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Section: Roofing Process In the Terasoma Formationmentioning

confidence: 99%

Section: Unroofing In the Otonashigawa Accretionary Sequencementioning

confidence: 99%

Section: Unroofing In the Otonashigawa Accretionary Sequencementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

How are the roofing and unroofing processes reflected in sandstone composition? —A case study in the Shimanto Belt, Kii Peninsula, southwestern Japan—

Bessho

2015

Jour. Sed. Soc. Japan

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Cordilleran‐type orogeny and episodic growth of continents: Insights from the circum‐Pacific continental margins

Tagami

Hasebe

1999

Island Arc

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A new material migration hypothesis for the plate subduction zone orogeny, so‐called ‘the cordilleran‐type orogeny’, is proposed on the basis of geological constraints as well as mechanics of accretionary wedges. The major tectonic processes of the hypothesis comprise: (i) episodic, extensive magmatism along the margin of an overriding plate; (ii) supply of voluminous igneous and eroded materials through forearc to trench, with an increase in the net sediment influx into trench; (iii) accelerated accretion of sediments beneath an overriding older accretionary wedge; and (iv) upward material migration within the wedge and resultant exhumation of high‐P/T metamorphic rocks near the inland margin of the wedge. This hypothesis was validated by the test using available geo‐ and thermo‐chronological data from two classical types of subduction‐related orogens in Southwest Japan and California. The hypothesis, coupled with the thermochronologic point of view, requires the reconsideration of coevality of paired metamorphism. The temporal pairing is to be observed between the beginning of the regional high‐T/P metamorphism and that of the uplift and exhumation of high‐P/T metamorphism, with some time lag needed for material migration. Where the temporal pairing is examined therefore, the formation age of igneous rocks and related high‐T/P metamorphic rocks should be compared to the exhumation age of high‐P/T metamorphic rocks. The episodic, extensive magmatism that triggers the cordilleran‐type orogeny shows a temporal correlation in the mid‐Cretaceous for most circum‐Pacific continental margins. The resultant widespread formation of accretionary complexes is also observed in the western part of the circum‐Pacific margins. The deduced mid‐Cretaceous circum‐Pacific orogeny accompanied a gross increase in the continental crust production rate, and was approximately coeval with the Pangea breakup and the Central Pacific superplume episode, implying the orogeny as a part of the mid‐Cretaceous pulsation of the Earth.

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Evolution of the Shimanto accretionary complex: A fission-track thermochronologic study

Hasebe¹,

Tagami²,

Nishimura³

1993

Geological Society of America Special Papers

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To place thermotectonic constraints on the evolution of the Cretaceous to Neogene Shimanto Belt, we carried out fission-track (FT) analyses of detrital apatite and zircon collected from both sandstone turbidites and blocks in mélanges on the Muroto Peninsula, Shikoku. Eight FT apatite ages show good agreement around 10 Ma, with all data except for one passing the x 2 test. These results, in conjunction with depositional ages of Cretaceous to early Oligocene, demonstrate that the Shimanto Belt was heated hotter than ~125°C (apatite total annealing temperature) and subsequently cooled below ~100°C at -10 Ma. The cooling pattern is attributed to higher thermal gradients and/or uplift caused by rapid subduction of the newly formed Shikoku Basin at -15 Ma. On the other hand, 23 zircon samples show a large range of sample ages from 150 to 17 Ma, with all failing the x 2 test except for one from a mélange. Hence, most parts of the Shimanto Belt have not been heated above the zircon partial annealing zone (ZPAZ; -190 to 260°C), whereas some parts of the mélanges have experienced temperatures above 260°C. FT age spectra of zircon single-grain data show that in the Northern Shimanto Belt (NSB) the youngest peak in each sample is younger than its depositional age, suggesting the maximum temperature was in the ZPAZ. In contrast, all age peaks from the Southern Shimanto Belt (SSB), are consistently older than depositional ages, providing no evidence of heating up to ZPAZ. These contrasting patterns probably reflect systematic differences in the maximum temperature reached during the evolution of the Shimanto Belt. The age-temperature paths estimated for individual tectonic units suggest successive accretion, growth, and uplift of offscraped imbricate packages as well as underplating of mélanges beneath them in an accretionary wedge.

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

Cited by 6 publications

References 14 publications

How are the roofing and unroofing processes reflected in sandstone composition? —A case study in the Shimanto Belt, Kii Peninsula, southwestern Japan—

How are the roofing and unroofing processes reflected in sandstone composition? —A case study in the Shimanto Belt, Kii Peninsula, southwestern Japan—

Cordilleran‐type orogeny and episodic growth of continents: Insights from the circum‐Pacific continental margins

Evolution of the Shimanto accretionary complex: A fission-track thermochronologic study

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