Sedimentary cycles and environments in the middle-late Pleistocene Shimosa Group, Boso Peninsula, central Japan.

Tokuhashi, Shuichi; Kondo, Yasuo

doi:10.5575/geosoc.95.933

Cited by 36 publications

(11 citation statements)

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“…450-80 ka), an upper sequence of the Kazusa Group which had filled the Middle Pleistocene paleo-Tokyo Bay in response to glacioeustatic sea level changes. Several previous chronostratigraphic frameworks for the Shimosa Group have reconstructed its depositional environments in relation to the ages of the formations (Tokuhashi and Kondo, 1989;Ito and O'Hara, 1994;Nishikawa and Ito, 2000).…”

Section: Age Of the Backslope Of The Sandstone Hillmentioning

confidence: 99%

Long-term denudation rates of actively uplifting hillcrests in the Boso Peninsula, Japan, estimated from depth profiling of in situ-produced cosmogenic 10Be and 26Al

et al. 2006

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Section: Age Of the Backslope Of The Sandstone Hillmentioning

confidence: 99%

Long-term denudation rates of actively uplifting hillcrests in the Boso Peninsula, Japan, estimated from depth profiling of in situ-produced cosmogenic 10Be and 26Al

et al. 2006

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“…Since Clifton and Thompson's (1978) original description of M. segregatis, the trace fossil has been recognized in a number of other Cambrian to Pleistocene successions: Caledonides, Norwegian (Knaust, 2004); Upper Jurassic of Milne Land, Greenland (Heinberg, 1974;Fürsich, 1984); Bluesky Formation, Alberta (MacEachern and Pemberton, 1992); Cadotte Member, Alberta (MacEachern and Pemberton, 1992;Saunders et al, 1994); Dunvegan Formation, Alberta (Gingras et al, 1998); Bearpaw-Horseshoe Canyon Formation transition, Alberta ( Fig. 1; Saunders, 1989;Saunders, et al, 1990;Pemberton and Saunders, 2003); Shimosa Group, Japan (Tokuhashi and Kondo, 1989); Narita Formation, Japan (Kikuchi, 1972); Shimosa and Kazusa Groups, Japan (Nara, 1994); and the Kujukurihama Coast, Japan (Nara and Seike, 2004). More recently, Savrda and Uddin (2005) described large Macaronichnus in the Eutew Formation, which exhibit distinctive mineralogical segregation.…”

Section: Introductionmentioning

confidence: 95%

“…Clifton and Thompson (1978) examined the activities of Ophelia limacina, which is interpreted to reject heavy mineral grains, micas, and aggregates of clays through the concentration of these grains within the organism's ventral groove. The isopod Excirolana chiltoni japonica also has been employed to explain the formation of Macaronichnus segregatis (Kikuchi, 1972;Tokuhashi and Kondo, 1989;Yokokawa and Masuda, 1991). However, experimental observations by Nara (1994) illustrated that a felsic grain selective worm, rather than E. chiltoni, likely constructed M. segregatis.…”

Section: Introductionmentioning

confidence: 97%

Analysis of Mineral Segregation inEuzonus mucronataBurrow Structures: One Possible Method Used in the Construction of AncientMacaronichnus segregates

Dafoe

Gingras

Pemberton

2008

Ichnos

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Mineralogical segregation of sand grains distinguishes the trace fossil Macaronichnus segregatis, which is composed of a felsic burrow infill with a mafic-and mica-rich burrow mantle. This study focuses on determining the mechanism by which M. segregatis trace-makers segregated mineral grains during deposit feeding. A modern opheliid polychaete, Euzonus mucronata, from Pachena Bay, Vancouver Island (Canada), was examined to explain the activities of their ancient counterparts. Microscopic videotaping of deposit feeding allowed for collection of data on ingestion and excretion through visual grain counts of felsic, mafic, and shell components. Normalization of these grain counts to the composition of the host sediment illustrates preferential ingestion of felsic grains over mafic. Shell fragments were generally avoided and visually mantled the burrows, obscuring the paucity of mafic grains in burrow infills. The avoidance of shell fragments is potentially a function of the large grain size, angular shape, surface texture, and/or associated low nutritive value. The preferential ingestion of felsic grains is attributed to en masse feeding in felsic-rich locales identified through sediment probing. This form of mineral segregation likely reflects the specific nature of the sediment and worm population. Accordingly, en mass deposit feeding in selected felsic-rich localities is one possible mechanism used in the construction of Macaronichnus segregatis and M. segregatis-like structures.

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“…The first correlation of onland, unconformity-bounded, shallow-water sedimentary sequences with the oceanic oxygen isotope scale was that of Kamp (1978; Pleistocene of eastern North Island, New Zealand). Sedimentological studies of cyclothems (unconformity-bounded sequences) from California (Clifton et al, 1988), Japan (Tokuhashi and Kondo, 1989), and New Zealand (Abbott et al, 1989;Haywick et al, 1992) followed .…”

Section: Application Of Sequence Interpretation To Pliocene-pleistocementioning

confidence: 99%

Sedimentary cyclicity in the marine Pliocene-Pleistocene of the Wanganui basin (New Zealand): Sequence stratigraphic motifs characteristic of the past 2.5 m.y.

Saul

Naish

Abbott

et al. 1999

Geological Society of America Bulletin

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Earth's climatic history since 2.5 Ma has been controlled by Milankovitch variations in the planetary orbit, comprising alternate periods of glaciation and interglaciation with a dominant frequency of 41 000 yr. Concomitantly, eustatic sea level has fluctuated 70 to 130 m, causing rapid transgressions and regressions of the shoreline across the world's continental shelves. The resulting sedimentary record is cyclothemic, each cyclothem corresponding to a single climate and sea-level cycle. The Wanganui basin, New Zealand, contains a 2-km-thick, almost complete, composite record since isotope stage 100 (ca. 2.5 Ma) in the form of 47 superposed cyclothems of shelf origin. Each cyclothem corresponds to an unconformity-bound stratigraphic sequence, and typically contains a transgressive systems tract, sometimes a mid-cycle shell bed, a highstand systems tract, and sometimes a regressive systems tract. No advantage accrues from using transgressive-regressive units rather than cyclothems and/or sequences in description of the succession. Six basic sequence motifs represent deposition in locations between the shoreline and offshore shelf, i.e., the Hawera, Birdgrove, Turakina, Seafield, Castlecliff, and Rangitikei motifs. A seventh, the Nukumaru motif (which includes dominant coquina limestone), represents deposition in shallow-water areas of reduced terrigenous sediment on the flank of the basin. The sequence motifs represented in any section change systematically in sympathy with basin-scale changes in subsidence and sediment supply. In contrast with the 41000 year length of individual glacio-eustatic sequences, these basin-wide tectonic cycles have a periodicity of many hundreds of thousands to a few million years, i.e., that of third-or fourth-order sequences of the Exxon type. This, coupled with the restriction of strongly cyclothemic sediments to geological periods of known glacio-eustasy (Permian-Carboniferous, Pliocene-Pleistocene), suggests that tectonic subsidence cycles rather than glacio-eustasy are the driving forces behind the development of the third-and fourth-order unconformity-bound sequences that are reported to occur throughout the stratigraphic record.

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Sedimentary cycles and environments in the middle-late Pleistocene Shimosa Group, Boso Peninsula, central Japan.

Cited by 36 publications

References 0 publications

Long-term denudation rates of actively uplifting hillcrests in the Boso Peninsula, Japan, estimated from depth profiling of in situ-produced cosmogenic 10Be and 26Al

Long-term denudation rates of actively uplifting hillcrests in the Boso Peninsula, Japan, estimated from depth profiling of in situ-produced cosmogenic 10Be and 26Al

Analysis of Mineral Segregation inEuzonus mucronataBurrow Structures: One Possible Method Used in the Construction of AncientMacaronichnus segregates

Sedimentary cyclicity in the marine Pliocene-Pleistocene of the Wanganui basin (New Zealand): Sequence stratigraphic motifs characteristic of the past 2.5 m.y.

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