Toya ash - A widespread late quaternary time-marker in northern Japan.

Machida, Hiroshi; Arai, Fusao; Miyauchi, Takashi; Okumura, Koji

doi:10.4116/jaqua.26.2_129

Cited by 50 publications

(34 citation statements)

References 4 publications

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“…They found the Toya and On‐PmI tephras in the Upper part of the Onikobe Formation in the eastern region of the basin. The Toya tephra is dated 90–100 ka BP (Machida et al ., 1987), and the On‐PmI tephra 80 ka BP (Machida et al ., 1985). A thickness of 1 m separates the two tephras, which implies that 1 m of sediment represents 10–20 ka of deposition.…”

Section: Geological Settingsupporting

confidence: 84%

Towards establishing criteria for identifying trigger mechanisms for soft‐sediment deformation: a case study of Late Pleistocene lacustrine sands and clays, Onikobe and Nakayamadaira Basins, northeastern Japan

Jones¹,

Omoto²

2000

Sedimentology

142

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Five main deformation units, discrete sheets of deformed sediments that lie between a significant thickness of undeformed sediment, were selected for study within Late Pleistocene lacustrine sands and clays in the Onikobe and Nakayamadaira Basins, northeastern Japan. The deformed units show evidence of deformation by a variety of mechanisms including fluidization, liquefaction, brittle failure and cohesive flow. Driving forces are thought to be primarily reverse density gradient systems, but also include gravitational body force, shear stress and unequal loading. The main trigger mechanisms are firstly earthquakes, secondly overloading from volcanic sands and thirdly, to a lesser extent, subaqueous currents. Consideration is given to criteria that allow the trigger mechanism to be identified. This study shows that the following criteria can be used to identify a seismic triggering agent: (i) setting; (ii) the extent of the deformation units; (iii) absence of evidence relating to other potential trigger mechanisms; and (iv) evidence relating to other potential trigger mechanisms is present but can be seen elsewhere in the stratigraphic section associated with undeformed sediment. Conversely, the following criteria, while they are important in interpreting the driving force and deformation mechanism, have no relevance to the trigger mechanism: (i) sediment composition; (ii) deformation structures being restricted to a single stratigraphic interval (<1 m thick) (not necessarily correlatable over large areas); and (iii) similarity to structures in the literature.

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Section: Geological Settingsupporting

confidence: 84%

Towards establishing criteria for identifying trigger mechanisms for soft‐sediment deformation: a case study of Late Pleistocene lacustrine sands and clays, Onikobe and Nakayamadaira Basins, northeastern Japan

Jones¹,

Omoto²

2000

Sedimentology

142

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“…In the final phase of volcanic activity, pyroclastic flows accompanied widespread air-fall products. The air-fall products are widely identified as a horizon in terrace deposits in northern Japan and used as a "marker horizon" for stratigraphic correlation of the early stage in the late Pleistocene (Machida et al, 1987). Though it is evident that the eruption age is later than marine oxygen isotopic stage (OIS) 5e (Machida et al, 1987), additional research is still necessary for final age determinations of the activity.…”

Section: Sampling Sitesmentioning

confidence: 99%

Single grains dating of volcanic quartz from pyroclastic flows using Red TL

Ganzawa

Furukawa

Hashimoto

et al. 2005

Radiation Measurements

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“…An ϳ 40-cm-thick widespread tephra, Toya, is intercalated with the silty sandstone in the lower part (Machida et al 1987) and the other widespread tephra, Aso-4, is intercalated with the silty sandstone in the middle part of the Katanishi Formation (Shiraishi et al 1992). The age and oxygen isotope substage attributions of B-Og, Aso-1, and Toya have been estimated as 448 Ϯ 20 ka (substage 12.2), 255 Ϯ 20 ka (substage 8.2), and 112 Ϯ 5 ka (substage 5.4), respectively, by .…”

Section: Geologic Settingmentioning

confidence: 99%

Sedimentary Successions Formed by Fifth-Order Glacio-Eustatic Cycles in the Middle to Upper Quaternary Formations of the Oga Peninsula, Northeast Japan

Shirai¹,

Tada²

2000

Journal of Sedimentary Research

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The northern coast of the Oga Peninsula is a type locality for Quaternary sedimentary exposures on the Sea of Japan side of northeast Japan. Middle to late Pleistocene shallow marine to nonmarine sediments are continuously exposed on sea cliffs along the Anden Coast. These sediments have been mapped and classified into nine sedimentary facies, based on grain size, sedimentary structures, intensity of bioturbation, and associated fossils. The depositional environments and paleo-water depths of each facies have been estimated, based on comparison with the present sub-bottom sedimentary features observed in coastal systems around the Oga Peninsula. On the basis of sedimentary facies analysis, variations in the depositional depth through time have been reconstructed and correlated with the SPEC-MAP ␦ 18 O curve, using four marker tephras as time controls. The two curves generally agree between approximately 80 and 450 ka, suggesting that the sedimentary cycles at the Anden Coast faithfully record 5th-and 6th-order glacio-eustatic sea-level changes. Peak-to-peak comparison between the reconstructed depositional depth curve and the ␦ 18 O curve reveals that (1) unconformities are formed during the late eustatic sea-level falls and/or the following lowstands, (2) transgressive lag deposits are mainly formed below wave base, (3) deepening-upward successions, which sometimes occur below the ravinement surfaces, are formed in the inner part of estuary or barrier-island environments where wave action was minor, (4) shoaling-upward successions formed during eustatic sea-level falls are deposited under the influence of intense wave action in a strand plain-coastal plain system, and (5) the characteristic combination of thinner deepening-upward successions and thicker shoaling-upward successions reflects the asymmetric pattern of glacio-eustatic sea-level changes and/or lower sediment supply during transgression.

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Toya ash - A widespread late quaternary time-marker in northern Japan.

Cited by 50 publications

References 4 publications

Towards establishing criteria for identifying trigger mechanisms for soft‐sediment deformation: a case study of Late Pleistocene lacustrine sands and clays, Onikobe and Nakayamadaira Basins, northeastern Japan

Towards establishing criteria for identifying trigger mechanisms for soft‐sediment deformation: a case study of Late Pleistocene lacustrine sands and clays, Onikobe and Nakayamadaira Basins, northeastern Japan

Single grains dating of volcanic quartz from pyroclastic flows using Red TL

Sedimentary Successions Formed by Fifth-Order Glacio-Eustatic Cycles in the Middle to Upper Quaternary Formations of the Oga Peninsula, Northeast Japan

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