scholarly journals Taxonomy of the fossil marine diatom resting spore morpho-genera <i>Xanthioisthmus</i> Suto gen. nov. and <i>Quadrocistella</i> Suto gen. nov. in the North Pacific and Norwegian Sea

2006 ◽  
Vol 25 (1) ◽  
pp. 3-22 ◽  
Author(s):  
Itsuki Suto
Keyword(s):  
North Pacific ◽  
Marine Diatom ◽  
Northwest Pacific ◽  
New Genera ◽  
Norwegian Sea ◽  
The North ◽  
Resting Spore ◽  
Resting Spores ◽  
Diatom Genus ◽  
The North Pacific

Abstract. The morphology and taxonomy of the fossil diatom resting spore morpho-genera Xanthioisthmus Suto gen. nov. and Quadrocistella Suto gen. nov. are described. The two new genera are probably fossil resting spores of the marine diatom genus Chaetoceros. They were studied by examining samples from DSDP Sites 436, 438 (northwest Pacific) and 338 (Norwegian Sea), and the Newport Beach Section (California). The genus Xanthioisthmus is characterized by an elongate valve composed of two flat circles joined together by a hyaline broad isthmus and includes five species: X. biscoctiformis (Forti) Suto comb. nov., X. specticularis (Hanna) Suto comb. nov., X. panduraeformis (Pantocsek) Suto comb. nov., X. praemaculata sp. nov. and X. maculata (Hanna) Suto comb. nov. The genus Quadrocistella differs from Xanthioisthmus by its elongate and rectangular valve and bears five new species: Q. rectagonuma sp. nov., Q. tubera sp. nov., Q. paliesa sp. nov., Q. montana sp. nov. and Q. palmesa sp. nov.

scholarly journals Strengthened Relationship between Tropical West Pacific and Midsummer Precipitation over Northeast China after the Mid-1990s

2020 ◽  
Vol 33 (16) ◽  
pp. 6833-6848
Author(s):  
Tingting Han ◽  
Minghua Zhang ◽  
Botao Zhou ◽  
Xin Hao ◽  
Shangfeng Li
Keyword(s):  
North Pacific ◽  
Northeast China ◽  
Aleutian Islands ◽  
Northwest Pacific ◽  
West Pacific ◽  
The North ◽  
Circulation Anomalies ◽  
The Relationship ◽  
The North Pacific ◽  
Central North Pacific

AbstractThe relationship between the tropical west Pacific (TWP) and East Asian summer monsoon/precipitation has been documented in previous studies. However, the stability for the signals of midsummer precipitation in the TWP sea surface temperature (SST_TWP), which is important for climate variation, has drawn little attention. This study identifies a strengthened relationship between the leading empirical orthogonal function mode (EOF1) of midsummer precipitation over Northeast China (NEC) and the SST_TWP after the mid-1990s. The EOF1 mode shows a significant positive correlation with the SST_TWP for 1996–2016, whereas the relationship is statistically insignificant for 1961–90. Further results indicate that the North Pacific multidecadal oscillation (NPMO) shifts to a positive phase after the 1990s. In the positive NPMO phase, the anomalous circulation over the northeast Pacific expands westward over the central North Pacific–Aleutian Islands region. Concurrently, the SST_TWP-associated wavelike pattern propagates northeastward from the west Pacific to the northwest Pacific and farther to the North Pacific, facilitating the poleward expansion and intensification of the SST_TWP-related circulation anomalies over the North Pacific. Therefore, the SST_TWP has an enhanced influence on NEC precipitation through the modulation of the circulation anomalies over the central North Pacific–Aleutian Islands region after the mid-1990s. Additionally, the tropical anticyclone/cyclone associated with the SST_TWP expands westward to South China, exerting an intensified impact on meridional wind anomalies along eastern China and on moisture transport over NEC. These conditions jointly contribute to the strengthened relationship between the SST_TWP and the EOF1 mode of NEC midsummer precipitation after the mid-1990s.

Methods and Applications of Cenozoic Marine Diatom Biostratigraphy

2007 ◽  
Vol 13 ◽  
pp. 61-83 ◽  
Author(s):  
Reed P. Scherer ◽  
Andrey Yu. Gladenkov ◽  
John A. Barron
Keyword(s):  
North Pacific ◽  
Marine Diatom ◽  
Diatom Assemblages ◽  
Ocean Drilling ◽  
The North ◽  
Planktonic Diatom ◽  
Low Latitudes ◽  
The Antarctic ◽  
The North Pacific ◽  
Early Paleogene

Diatoms provide the chief Cenozoic biostratigraphic tool in marine sediments beneath high primary productivity zones, especially where calcareous fossils are rare or poorly preserved. Diatom biostratigraphy, which is based on originations and extinctions of unique taxa, is especially useful in circum-Antarctic, equatorial Pacific, and high latitude North Pacific marine successions, which are available largely from ocean drilling. Oligocene to Holocene diatom biostratigraphic zonations are correlated with the geopaleomagnetic timescale, resulting in age control of million-year to as little as hundred-thousand year resolution. Paleocene and Eocene zonations are less well developed and have lower chronostratigraphic control, but are more widely applicable, because planktonic diatom assemblages of the globally warm early Paleogene were less provincial. We review the principals and methods of biostratigraphy and the application of diatoms to age control in stratigraphic successions worldwide. Distinct biostratigraphic zonations defined for the low latitudes, the North Pacific and the Antarctic, are reviewed, and Atlantic records and Antarctic coastal records are discussed. New biostratigraphic tools are introduced, including multidimensional graphic correlation of published diatom ranges.

A revised inoceramid biozonation for the Upper Cretaceous based on high-resolution carbon isotope stratigraphy in northwestern Hokkaido, Japan

2013 ◽  
Vol 63 (2) ◽  
pp. 239-263 ◽  
Author(s):  
Tatsuya Hayakawa ◽  
Hiromichi Hirano
Keyword(s):  
High Resolution ◽  
Carbon Isotope ◽  
North Pacific ◽  
Upper Cretaceous ◽  
Northwest Pacific ◽  
Terrestrial Organic Matter ◽  
Carbon Isotope Stratigraphy ◽  
The North ◽  
Isotope Stratigraphy ◽  
The North Pacific

Abstract Hayakawa, T., Hirano, H. 2013. A revised inoceramid biozonation for the Upper Cretaceous based on high-resolution carbon isotope stratigraphy in northwestern Hokkaido, Japan. Acta Geologica Polonica, 63 (2), 239-263. Warszawa. Biostratigraphic correlations of inoceramid bivalves between the North Pacific and Euramerican provinces have been difficult because the inoceramid biostratigraphy of the Japanese strata has been based on endemic species of the northwest Pacific. In this study, carbon stable isotope fluctuations of terrestrial organic matter are assembled for the Upper Cretaceous Yezo Group in the Haboro and Obira areas, Hokkaido, Japan, in order to revise the chronology of the inoceramid biozonation in Japan. The carbon isotope curves are correlated with those of marine carbonates in English and German sections with the aid of age-diagnostic taxa. According to the correlations of the carbon isotope curves, 11 isotope events are recognised in the sections studied. As a result of these correlations, the chronology of the inoceramid biozones of the Northwest Pacific has been considerably revised. The revised inoceramid biozones suggest that the timing of the origination and extinction of the inoceramids in the North Pacific biotic province is different from the stage/substage boundaries defined by inoceramids, as used in Europe and North America.

Enhanced storm activities triggered the North Pacific deep convection during the Younger Dryas event

2020 ◽  
Author(s):  
Xiaopei lin ◽  
Cunjie Zhang
Keyword(s):  
North Pacific ◽  
Deep Convection ◽  
Younger Dryas ◽  
Meridional Overturning Circulation ◽  
Northwest Pacific ◽  
Turbulent Heat ◽  
Surface Salinity ◽  
The North ◽  
Younger Dryas Event ◽  
The North Pacific

&lt;p&gt;The occurrence of deep convection could redistribute ocean heat and materials, and induce robust climate and biogeochemical changes. The convection in the North Pacific is quite shallow now (typically 300-m), but paleo records and model simulations suggest that it might reach 2000-3000 m during stadials in the last deglaciation, such as the Heinrich event 1 (H1: ~17.5-15 ka) and Younger Dryas event (YD: ~12.8-11.5 ka). The deep convection during H1 has been explained by increased North Pacific surface salinity due to evaporation and precipitation changes, but this explanation conflicts with many paleo records for YD. Here we collected published paleo records in the northwest Pacific and carried out simulations for the YD period. We show that due to the weakened Atlantic Meridional Overturning Circulation (MOC) during YD, the oceanic Meridional Heat Transport (MHT) weakened. According to the Bjerknes compensation, the atmospheric MHT strengthened. Because atmospheric MHT mainly occurs through baroclinic eddies in extratropics, storm activities strengthened. The strengthened wintertime storm activities induced more oceanic turbulent heat loss and triggered deep convections in the North Pacific, and further contributed to a seesaw pattern of MOC strengths between the North Pacific and North Atlantic. Our result not only provides a new explanation for the North Pacific deep convection during YD but also suggest that synoptic-scale atmospheric variations are capable of influencing low-frequency paleoclimate changes.&lt;/p&gt;

scholarly journals Revision of Metaconchoecia (Ostracoda: Halocyprididae) and the designation of two new tribes Conchoeciini and Metaconchoeciini

Zootaxa ◽  
2011 ◽  
Vol 2857 (1) ◽  
pp. 1 ◽  
Author(s):  
VLADIMIR G. CHAVTUR ◽  
MARTIN V. ANGEL
Keyword(s):  
New Species ◽  
North Pacific ◽  
Type Species ◽  
New Genera ◽  
The North ◽  
New Tribe ◽  
The North Pacific ◽  
A New Species ◽  
Size Data ◽  
Pelagic Ostracoda

A new tribe of pelagic Ostracoda (Halocyprididae), the Metaconchoeciini, is established to encompass all the species formerly classified in the genus Metaconchoecia. All the remaining genera in the subfamily Conchoecinae are, therefore, assigned to another new tribe, the Conchoeciini. The original genus Metaconchoecia is subdivided into ten genera. Metaconchoecia is retained and nine new genera established namely: Austrinoecia, Clausoecia, Deeveyoecia, Juryoecia, Kyrtoecia, Muelleroecia, Nasoecia, Rotundoecia and Vityazoecia. Keys to these new genera and their component species are provided. Tables summarize the characters that most readily distinguish between the most closely related taxa. Appendices summarize the taxonomic characters and detailed size data for the majority of species that occur in the Atlantic and the North Pacific. A new species, Vityazoecia distoglandula, is described, which is designated as the type species of its genus.

Was deep water formed in the North Pacific during the Late Quaternary? Cadmium evidence from the Northwest Pacific

1994 ◽  
Vol 124 (1-4) ◽  
pp. 185-194 ◽  
Author(s):  
N. Ohkouchi ◽  
H. Kawahata ◽  
M. Murayama ◽  
M. Okada ◽  
T. Nakamura ◽  
...  
Keyword(s):  
Deep Water ◽  
North Pacific ◽  
Late Quaternary ◽  
Northwest Pacific ◽  
The North ◽  
The North Pacific
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