Genetic relationship between the Cretaceous high-Sr tonalite (Itoshima mass) and trondhjemite (Fukae mass) in the central part of Saga Prefecture, northwest Kyushu: Implications for magmatic differentiation

純, 矢田; 正明, 大和田

doi:10.5575/geosoc.109.518

Cited by 15 publications

(4 citation statements)

References 9 publications

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“…67 (2), 2016 A Bulletin of the Geological Survey of Japan,vol. 67 (2) et al, 2000) and Ryoke belt (Katsuragi Granitoids; Nishioka, 2008), also in the northern part of the Kyushu District (Izawa et al, 1990;Yada and Owada, 2003;Kamei, 2004). Ba may have the same trend as the Sr plotted, but the figure is somewhat erratic (Fig.…”

Section: Results Of Analyses and Discussion On The North-south Chemicamentioning

confidence: 90%

Geochemical variation of the Late Cretaceous-Paleogene granitoids across the Ehime-Hiroshima-Shimane transect, Japan

Ishihara

Ohno

2016

Bull. Geol. Surv. Japan

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Section: Results Of Analyses and Discussion On The North-south Chemicamentioning

confidence: 90%

Geochemical variation of the Late Cretaceous-Paleogene granitoids across the Ehime-Hiroshima-Shimane transect, Japan

Ishihara

Ohno

2016

Bull. Geol. Surv. Japan

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“…These features of adakites are generally interpreted to indicate a slab melting origin (e.g., Defant and Drummond 1990). However, the possibility of an origin controlled by intracrustal differentiation processes continues to be debated (e.g., Yada and Owada 2003;Kamei et al 2004;Takahashi et al 2005;Takahashi 2008;Tsuchiya 2008;Chiaradia 2015;Chapman et al 2015). HMA magmatism is thought to be associated with partial melting of mantle under relatively low-pressure conditions with hydrated conditions (Tatsumi 1982(Tatsumi , 1995.…”

Section: Adakitic Magma and High-mg Andesitic Magmamentioning

confidence: 99%

Clockwise rotation of SW Japan and timing of Izanagi–Pacific ridge subduction revealed by arc migration

Yamaoka,

Wallis

2023

Prog Earth Planet Sci

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Igneous rocks associated with the Cretaceous to Paleogene volcanic arc in SW Japan show ages that young from west to east in a direction parallel to the Median Tectonic Line suggesting corresponding translation of a heat source traditionally interpreted in terms of oblique subduction of a spreading ridge. However, recent oceanic plate reconstructions suggest ridge subduction may be younger than the main arc activity. Age compilations of 1227 points of felsic to intermediate Cretaceous and Cenozoic igneous rocks from the Japan arc show arc magmatism that can be separated into an early active period 130–60 Ma (stage 1), a subsequent period of quiescence 60–46 Ma (stage 2), which is followed by a resumption of igneous activity from 46 Ma onward (stage 3). In southwest Japan, the orientations of the magmatic arcs of stages 1 and 3 show and angular discordance of about 20°. The lack of active arc magmatism and the occurrence patterns of adakitic and high-Mg andesitic magmas indicate that ridge subduction occurred during stage 2. The arc age distribution pattern of stage 1 is explained by the slab shallowing related to a younging of the subducting slab as the ridge approaches. Furthermore, the obliquity of the arcs formed at stages 1 and 3 is explained by a 20° clockwise rotation of the inner zone of southwest Japan during the ridge-subduction phase. Oceanic plate reconstructions show counterclockwise rotation in the subduction direction after the ridge subduction phase, and coupling of the subducting oceanic plate with the upper plate would support microplate rotation in the inner zone. The new proposed tectonic reconstructions provide a framework to related Paleogene subduction of an active spreading ridge along the east Asia margin not only to the distribution of granitic bodies but also to rift-related basin formation on the eastern margin of the Eurasian continent and to rotation of crustal blocks indicated by paleomagnetic data of Cretaceous terranes.

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“…A few Cretaceous adakitic rocks have been reported in SW Japan such as Tamba (<10 km 2 , Kiji et al . ), Hisori (10 km 2 , Yuhara ), Saga (200 km 2 , Yada & Owada ) and Higo (15 km 2 , Kamei ) as shown in Figure a, although they are expressed as spots due to the limited exposed areas. Based on the K–Ar biotite age and Rb–Sr isochron ages, Takahashi () pointed out that the adakitic magmatism started at around 110 Ma.…”

Section: Geological Setting and Samplesmentioning

confidence: 99%

“…) and adakitic rocks ( K iji et al . ; Y ada & O wada ; K amei ; Y uhara ) are plotted in F igure a.…”

Section: Introductionmentioning

confidence: 99%

Tectonic reconstruction of batholith formation based on the spatiotemporal distribution of Cretaceous–Paleogene granitic rocks in southwestern Japan

et al. 2015

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The spatiotemporal distribution of Cretaceous-Paleogene granitic rocks in southwestern Japan is investigated to understand the origin of the granitic batholith belt and to reconstruct the tectonic setting of emplacement. New U-Pb zircon ages for 92 samples collected from a region measuring 50 km (E-W) by 200 km (N-S) reveals a stepwise northward younging of granitic rocks aged between 95 and 30 Ma with an agedata gap between 60 and 48 Ma. Based on the spatiotemporal distribution of granite ages, we examine two plausible models to explain the pattern of magmatic activity: (i) subduction of a segmented spreading ridge and subsequent slab melting (ridge-subduction model), and (ii) subduction with a temporally variable subduction angle and corresponding spatial distribution of normal arc magmatism (subduction angle model). We optimize the model parameters to fit the observed magmatism in time and space, and compare the best-fit models. As to ridge subduction model, the best-fit solution indicates that the spreading ridge started to subduct at approximately 100 Ma, and involved a 45-km-wide section of the ridge segment, a subduction obliquity of 30°, and a slow migration velocity (∼1.6 cm/y) of the ridge. These values are within the ranges of velocities observed for present-day ridge subduction at the Chile trench. On the other hand, the best-fit solution of subduction angle model indicates that the subduction angle decreases stepwise from 37°at 95 Ma, 32°at 87 Ma, 22°at 72 Ma, to 20°at 65 Ma, shifting magmatic region towards the continental side. These results and comparison, together with constraints on the geometry of the tectonic setting provided by previous studies, suggest that the ridge subduction model better explains the limited duration of magmatism, although both models broadly fit the data and cannot be ruled out.

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Genetic relationship between the Cretaceous high-Sr tonalite (Itoshima mass) and trondhjemite (Fukae mass) in the central part of Saga Prefecture, northwest Kyushu: Implications for magmatic differentiation

Cited by 15 publications

References 9 publications

Geochemical variation of the Late Cretaceous-Paleogene granitoids across the Ehime-Hiroshima-Shimane transect, Japan

Geochemical variation of the Late Cretaceous-Paleogene granitoids across the Ehime-Hiroshima-Shimane transect, Japan

Clockwise rotation of SW Japan and timing of Izanagi–Pacific ridge subduction revealed by arc migration

Tectonic reconstruction of batholith formation based on the spatiotemporal distribution of Cretaceous–Paleogene granitic rocks in southwestern Japan

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