Cenozoic basin-forming processes along the northeastern margin of Eurasia: Constraints determined from geophysical studies offshore of Hokkaido, Japan

Formation and deformation processes of the late Paleogene sedimentary basins related to a strike-slip fault system in southern central Hokkaido are described by a combination of paleomagnetic study and numerical analysis. After correction of the Miocene counter-clockwise rotation associated with back-arc opening of the Japan Sea, paleomagnetic declination data obtained from surface outcrops in the Umaoi and Yubari areas show significant easterly deflections. Although complicated differential rotation is anticipated as a result of recent thrust movements, clockwise rotation in the study areas is closely linked with development of the Paleogene Minami-naganuma Basin as a pull-apart depression along the north-south fault system. Numerical modeling suggests that 30 km of strike-slip is required to restore the distribution and volume of the Minami-naganuma Basin. The relative slip rate on the long-standing fault system is about 10 mm/yr, which corresponds to global-scale plate motion. It has inevitably caused regional rearrangement of the eastern Eurasian margin. A rotation field simulated by simplified dextral motion using dislocation modeling basically accords with the paleomagnetic data around the pullapart basin.

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“…Recently, coeval north‐trending dextral motion was also reported in the northwestern area offshore of Hokkaido (Fig. 1) (Itoh et al. 2009).…”

Section: Introductionmentioning

confidence: 53%

Formation and deformation processes of late Paleogene sedimentary basins in southern central Hokkaido, Japan: Paleomagnetic and numerical modeling approach

2010

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“…Depocenters are aligned on the transcurrent fault system in conjunction with stepover portions of fault trace. From north to south, Itoh et al (2009), Tamaki et al (2010), and Itoh and Tsuru (2005) described synchronously developed pull-apart basins in the Ishikari-Teshio Belt. Among them, the Minaminaganuma basin, which is buried by the late Oligocene Minaminaganuma Formation (Kurita and Yokoi 2000) that is intercalated with numerous volcaniclastic layers (T2 and T3 zones in Figure 6), is the largest depression (Figure 7; southern basin in Minaminaganuma stage with maximum thickness of 2,000 m).…”

Section: Description Of Pull-apart Basinsmentioning

confidence: 99%

“…As for the northern part of the Ishikari-Teshio Belt, the timing of the remarkable contraction seems to have been later than that of the southern sector. Itoh et al (2009) showed that an offshore basin on the eastern margin of the Japan Sea accelerated the subsidence rate during the Quaternary, and a half-graben morphology developed. This is an indication of the emergence of the foreland basin setting (Allen and Allen 2005).…”

Section: Neogene Setting Sedimentary Environment During Opening Of Thmentioning

confidence: 99%

Mechanism of long-standing Cenozoic basin formation in central Hokkaido: an integrated basin study on an oblique convergent margin

Itoh

Takano

Kusumoto

et al. 2014

Prog Earth Planet Sci

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The basin-forming process along a convergent margin off the eastern coast of Eurasia was pursued on the basis of geological, geochemical, and geophysical approaches. Central Hokkaido has been a site of vigorous tectonic events throughout the Cenozoic reflecting the long-standing subduction of oceanic plates in the region. Geochemical modeling provided an estimate of the eroded Paleogene unit in the study area. Data on the considerable thickness of the missing unit implied continued subsidence of the forearc region and its subsequent exhumation under the emergence of a compressive regime synchronous with the back-arc opening stage. Spatially large facies variety in the Paleogene system suggests that basin compartmentalization occurred as a result of the trench-parallel component of the plate convergence. Right-lateral motion seems to have been the dominant type in Hokkaido and the forearc of northeast Japan since the Late Cretaceous, except for a left-lateral episode during rapid subsidence of the Izanagi Plate around 110 Ma. Numerical modeling demonstrated that dextral slip on a bunch of longitudinal strike-slip faults restored the Neogenedepocenters in central Hokkaido, together with an east-west compressive regime related to an arc-arc collision.

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“…It seems, however, that the configuration of the basin is best explained on the basis of the formation of pull-apart sags along a right-stepping dextral fault system. In the southern part of the Ishikari-Teshio Belt, Oka (1986) stated that the N-S dextral shearing, which was a regional deformation trend since the late Paleogene (Weaver et al, 2003;Itoh et al, 2009;Tamaki et al, 2010), lingered until the middle Miocene in central Hokkaido. We propose that the en echelon late Neogene troughs in Northern Hokkaido were probably developed as pull-apart basins in a transcurrent fault regime.…”

Section: Late Neogene Tectonic Regime In Northern Hokkaidomentioning

confidence: 99%

“…Kawakami et al, 1999;Kawakami & Kawamura, 2003). As for the northern part of the Ishikari-Teshio Belt, Itoh et al (2009) presented a chronicle of an offshore (eastern margin of the Japan Sea) basin that commenced as a Paleogene pull-apart sag on a dextral N-S fault system and transformed to a foreland basin under the emergence of an E-W compressive regime reflecting arc-arc collision since the late Neogene.…”

Section: Introductionmentioning

confidence: 99%

Magnetic properties of siliceous marine sediments in Northern Hokkaido, Japan: a quantitative tectono‐sedimentological study of basins along an active margin

2013

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The formation processes of the late Neogene sedimentary basins in Northern Hokkaido have been investigated on the basis of rock magnetism, structural geology and numerical modelling. Untilted site-mean directions of remanent magnetization of the Wakkanai Formation, obtained from oriented core samples in Horonobe, suggest remarkable counterclockwise block rotation (ca. 70°) since the late Neogene. Uniform microscopic fabric of the siliceous sediments was inferred from the alignment of the principal axes of the anisotropy of magnetic susceptibility (AMS). After correction for tectonic rotation, the maximum axis of AMS, which reflects the sedimentary fabric of the dominant paramagnetic minerals, is in an E-W direction, which is concordant with the influx direction of diatomaceous particles into the N-S elongate sedimentary basins. The difference in the bulk initial magnetic susceptibility of the siliceous sediments of the Wakkanai Formation between the depocenter of the basin and its peripheral part implies that terrigenous non-magnetic fraction has been sorted out during transportation of the detrital grains as gravity flows. As for the development mechanism of the N-S elongate late Neogene basins in Northern Hokkaido, their depocenter arrangement and subsidence pattern indicates dextral motions upon a longitudinal fault zone along the Eurasian convergent margin. Dislocation modelling was adopted to explain vertical displacement and rotational motion around the study area and successfully restored the deformation pattern based on the assumption of dextral slip at a left-stepping part of a strand of the transcurrent fault.

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Cenozoic basin-forming processes along the northeastern margin of Eurasia: Constraints determined from geophysical studies offshore of Hokkaido, Japan

Cited by 6 publications

References 28 publications

Formation and deformation processes of late Paleogene sedimentary basins in southern central Hokkaido, Japan: Paleomagnetic and numerical modeling approach

Formation and deformation processes of late Paleogene sedimentary basins in southern central Hokkaido, Japan: Paleomagnetic and numerical modeling approach

Mechanism of long-standing Cenozoic basin formation in central Hokkaido: an integrated basin study on an oblique convergent margin

Magnetic properties of siliceous marine sediments in Northern Hokkaido, Japan: a quantitative tectono‐sedimentological study of basins along an active margin

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