Holocene Fluctuation of the Warm Tsushima Current and Warm Molluscan Assemblages from Hokkaido, Japan.

Kito, Norio; Noda, Takashi; Minami, Toshitaka

doi:10.4116/jaqua.37.25

Cited by 11 publications

(7 citation statements)

References 2 publications

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“…3). Tsushima Current molluscs with ages ranging from 7200 to 5000 years BP, 4200 to 3200 years BP, 2500 to 2300 years BP, and 1000 to 900 years BP are also present in the coastal area along Hokkaido~43°N (Kito et al 1998;Matsushima 2010). This suggests periodic intensification of the northward inflow of the Tsushima Current.…”

Section: Late Pleistocene To Holocene Tsushima Currentmentioning

confidence: 99%

The Pliocene to recent history of the Kuroshio and Tsushima Currents: a multi-proxy approach

Gallagher

Kitamura

Iryu

et al. 2015

Prog. in Earth and Planet. Sci.

159

121

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The Kuroshio Current is a major western boundary current controlled by the North Pacific Gyre. It brings warm subtropical waters from the Indo-Pacific Warm Pool to Japan exerting a major control on Asian climate. The Tsushima Current is a Kuroshio offshoot transporting warm water into the Japan Sea. Various proxies are used to determine the paleohistory of these currents. Sedimentological proxies such as reefs, bedforms, sediment source and sorting reveal paleocurrent strength and latitude. Proxies such as coral and mollusc assemblages reveal past shelfal current activity. Microfossil assemblages and organic/inorganic geochemical analyses determine paleo-sea surface temperature and salinity histories. Transportation of tropical palynomorphs and migrations of Indo-Pacific species to Japanese waters also reveal paleocurrent activity. The stratigraphic distribution of these proxies suggests the Kuroshio Current reached its present latitude (35°N) by~3 Ma when temperatures were 1 to 2°C lower than present. At this time a weak Tsushima Current broke through Tsushima Strait entering the Japan Sea. Similar oceanic conditions persisted until~2 Ma when crustal stretching deepened the Tsushima Strait allowing inflow during every interglacial. The onset of stronger interglacial/glacial cycles~1 Ma was associated with increased North Pacific Gyre and Kuroshio Current intensity. This triggered Ryukyu Reef expansion when reefs reached their present latitude (~31°N), thereafter the reef front advanced (~31°N) and retreated (~25°N) with each cycle. Foraminiferal proxy data suggests eastward deflection of the Kuroshio Current from its present path at 24°N into the Pacific Ocean due to East Taiwan Channel restriction during the Last Glacial Maximum. Subsequently Kuroshio flow resumed its present trajectory during the Holocene. Ocean modeling and geochemical proxies show that the Kuroshio Current path may have been similar during glacials and interglacials, however the glacial mode of this current remains controversial. Paleohistorical studies form important analogues for current behavior with future climate change, however, there are insufficient studies at present in the region that may be used for this purpose. Modeling of the response of the Kuroshio Current to future global warming reveals that current velocity may increase by up to 0.3 m/sec associated with a northward migration of the Kuroshio Extension.

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Section: Late Pleistocene To Holocene Tsushima Currentmentioning

confidence: 99%

The Pliocene to recent history of the Kuroshio and Tsushima Currents: a multi-proxy approach

Gallagher

Kitamura

Iryu

et al. 2015

Prog. in Earth and Planet. Sci.

159

121

View full text Add to dashboard Cite

show abstract

“…Analysis of marine molluscan assemblage suggests that the Sea of Japan coast was warmest between 8 ka and 6 ka during the Holocene (Kito et al, 1998). This period is nearly coincident with the timing of the peak of July 65°N insolation at 10 ka.…”

Section: Methodsmentioning

confidence: 91%

Eccentricity cycles shown by early Pleistocene planktonic foraminifers of the Omma Formation, Sea of Japan

Kitamura

Kimoto

2007

Global and Planetary Change

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There is a continuous record of planktonic foraminifers for oxygen isotope stages 50 to 26 (ca. 1.5-1.0 Ma) in the early Pleistocene Omma Formation near Kanazawa City, Central Japan, on the Sea of Japan coast. The warm-water species Globigerinoides ruber entered the Sea of Japan with the Tsushima Current during all interglacial periods and went locally extinct in the succeeding glacial periods. This implies that the marine climate of the Sea of Japan varied predominantly with the 41,000-year period of Earth's orbital obliquity. However, the relative abundances of G. ruber in marine isotope stages 47, 43 and 31 are significantly higher than those in other interglacial stages. These stages correspond to periods when eccentricity-modulated precession extremes were aligned with obliquity maxima. The Tsushima Current is a branch of the warm Kuroshio Current which is the strong northwestern component of the subtropical North Pacific Ocean gyre. Our data imply that the early Pleistocene climate in the northwestern Pacific was influenced not only by obliquity cycles but also by eccentricity cycles. This study also supports the climate model regarding eccentricity's role in the origin of low-frequency climate changes before the late Pleistocene ice ages.

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“…The results are consistent with the occurrence of a molluscan assemblage including warm water species such as Meretrix lusoria, Mactra veneriformis, Umbonium moniliferum and others, which occurred in 5.0-4.0 and 2.4-2.3 cal. kyr BP in southern Hokkaido (Akamatsu et al, 1995;Kito et al, 1998).…”

Section: C37 Alkenone Sstmentioning

confidence: 99%

Climatic change and its relationship with human society in northern Japan since the mid-Holocene - Quantitative reconstruction of atmospheric and sea surface temperature -

Kawahata¹,

Hatta²,

Kajita³

et al. 2020

Preprint

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For the prediction for future climate, it is required to enhance our understanding of the Holocene climatic change. By estimating paleo-temperature, we attempted to examine the relationship between climatic changes and human activities in northern Japan. The alkenone SSTs showed a variation of 8.7 °C (14.5 °C to 23.2 °C). Jomon people living around Funka Bay were more dependent on marine products than in Honshu due to cooler climatic conditions. There are two Hypsithermal environments at Funka Bay around 4.6 cal. kyr BP and 1.2 cal. kyr BP. Sea levels for the last 7 kyrs have been controlled mainly by local/regional tectonic vertical movement. Therefore, the highstand never always corresponded to Hypsithermal environments. More than one driving forcing, rather than one, may control climatic/environmental change. The 4.2ka event in northern Japan could be characterized by cooling by a few degrees by the combination of reduced ESAM and El Niño mode. Another notable cooling event occurred in 1.0-0.8 cal. kyr BP due to the La Niña condition and reduced solar activities, which means that the Japanese archipelago never experienced Medieval Warm Event: instead, there was a Medieval Cold Event in Japan. The Okhotsk culture in Hokkaido prospered only under the Hypsithermal condition during the 5 th - 9 th centuries and subsequently it declined and was incorporated into the Satsumon culture under the cooler environmental conditions. For the Yayoi-era (2.9 cal. kyr BP-) and the following periods, our results are consistent with the previous results from Hiroshima Bay, western Japan, that cold periods (6 th - 7 th century BC, 3 rd century BC, 6 th century AD, 10 th -12 h century AD and 16 th century AD) coincided with major shifts in social systems in Japan.

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Holocene Fluctuation of the Warm Tsushima Current and Warm Molluscan Assemblages from Hokkaido, Japan.

Cited by 11 publications

References 2 publications

The Pliocene to recent history of the Kuroshio and Tsushima Currents: a multi-proxy approach

The Pliocene to recent history of the Kuroshio and Tsushima Currents: a multi-proxy approach

Eccentricity cycles shown by early Pleistocene planktonic foraminifers of the Omma Formation, Sea of Japan

Climatic change and its relationship with human society in northern Japan since the mid-Holocene - Quantitative reconstruction of atmospheric and sea surface temperature -

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