Evolution of the lithosphere of the Hawaiian-Emperor seamount chain, Pacific Ocean, as inferred from geophysical data

Geotectonics ◽  
2006 ◽  
Vol 40 (6) ◽  
pp. 467-480 ◽  
Author(s):  
E. V. Verzhbitsky ◽  
M. V. Kononov ◽  
A. F. Byakov ◽  
V. P. Dulub
Keyword(s):  
Pacific Ocean ◽  
Geophysical Data ◽  
Seamount Chain ◽  
Emperor Seamount Chain

Diagenetic manganese and iron cycling and implications for past redox conditions in sediments along the Emperor Seamount Chain, NW Pacific Ocean

2020 ◽  
Author(s):  
Sabine Kasten ◽  
Jessica Volz ◽  
Walter Geibert ◽  
Ingrid Stimac ◽  
Denise Bethke ◽  
...  
Keyword(s):  
Carbon Sequestration ◽  
Pacific Ocean ◽  
Pore Water ◽  
North Pacific ◽  
Oxygen Depletion ◽  
Redox Conditions ◽  
Northwest Pacific ◽  
The North ◽  
Seamount Chain ◽  
Emperor Seamount Chain

<p>The deep water of the North Pacific Ocean is enriched in CO<sub>2</sub> and nutrients as a result of organic matter degradation in the water column and surface sediments. Due to its large volume, the deep North Pacific may have played a fundamental role for the postulated glacial carbon sequestration leading to the observed drawdown of atmospheric CO<sub>2</sub>. As a consequence of increased CO<sub>2</sub> levels in the deep glacial ocean, bottom-water oxygen concentrations must have been correspondingly low compared to current oxygenated conditions (e.g., Anderson et al., 2019). Previous studies on sediments from the NW Pacific Ocean have provided evidence that glacial bottom‑water O<sub>2</sub> concentrations were significantly lower than today, which have induced suboxic surface sediment redox conditions (Jaccard et al., 2009) and have altered the primary sediment composition and properties of glacial deposits (e.g., magnetic susceptibility) due to diagenetic processes (Korff et al., 2016).</p><p>We have investigated seven 10- to 15-m-long sediment cores along a S-N transect at the Emperor Seamount Chain taken during RV SONNE cruise SO264 in order to (1) geochemically characterize the sediments and, (2) reconstruct past sediment redox conditions. The cores were retrieved from water depths between 3.5 and 5.7 km from organic-poor siliciclastic‑carbonaceous sediments in the South to more organic-rich siliciclastic‑siliceous sediments in the North with tephra layers found throughout all cores (Nürnberg et al., 2018).</p><p>Mn<sup>2+</sup> is released into the pore water at all study sites with increasing Mn<sup>2+</sup> concentrations below 20‑30 cm sediment depth. Pore-water Mn<sup>2+</sup> reraches up to 190 µM in siliciclastic‑siliceous sediments most likely associated with high rates of dissimilatory Mn(IV) reduction. The solid‑phase composition of a core taken from the Minnetonka Seamount (47°44’N, 168°40’E) at 4 km water depth shows Mn/Al ratios below 0.0003. These ratios are much lower than the average MORB Mn/Al value of 0.013 (Klein, 2004), which further indicates that Mn has been diagenetically lost from these sediments. As pore-water Fe<sup>2+</sup> concentrations are below detection limit at the Minnetonka Seamount and the depth distribution of solid-phase Fe/Al is mostly constant with ratios close to the average MORB Mn/Al value of 0.59 (Klein, 2004), Fe has probably not been diagenetically redistributed at this site. Pore‑water Fe<sup>2+</sup> concentrations of up to 20 µM are only found at two sites most likely as a result of dissimilatory Fe(III) reduction due to higher fluxes of organic material to the seafloor compared to the other sites.</p><p>References</p><p>Anderson, R.F., et al., 2019. Deep-sea oxygen depletion and ocean carbon sequestration during the last ice age. Global Biogeochem. Cycles 33, 301-317. </p><p>Jaccard, S.L., et al., 2009. Subarctic Pacific evidence for a glacial deepening of the oceanic respired carbon pool. Earth Planet. Sci. Lett. 277, 156‑165. </p><p>Klein, E.M., 2004. Geochemistry of the Igneous Oceanic Crust. In: Holland, H.D., Turekian, K.K. (Eds.), Treatise on Geochemistry, Vol.3. Elsevier, Amsterdam, pp. 433‑463.</p><p>Korff, L., et al., 2016. Cyclic magnetite dissolution in Pleistocene sediments of the abyssal northwest Pacific Ocean: evidence for glacial oxygen depletion and carbon trapping. Paleoceanography 31, 600‑624. </p><p>Nürnberg, D., 2018. RV SONNE Fahrtbericht /Cruise Report SO264, SONNE-EMPEROR, 30.6. – 24.8.2018. </p>

scholarly journals Geochemistry of Surface Sediments From the Emperor Seamount Chain, North Pacific

2021 ◽  
Vol 9 ◽  
Author(s):  
Jie Chen ◽  
Jianjun Zou ◽  
Aimei Zhu ◽  
Xuefa Shi ◽  
Dirk Nürnberg ◽  
...  
Keyword(s):  
Grain Size ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Water Depth ◽  
Surface Sediment ◽  
North Pacific ◽  
The North ◽  
Seamount Chain ◽  
The North Pacific ◽  
Emperor Seamount Chain

Investigating the composition and distribution of pelagic marine sediments is fundamental in the field of marine sedimentology. The spatial distributions of surface sediment are unclear due to limited investigation along the Emperor Seamount Chain of the North Pacific. In this study, a suite of sedimentological and geochemical proxies were analyzed, including the sediment grain size, organic carbon, CaCO3, major and rare earth elements of 50 surface sediment samples from the Emperor Seamount Chain, spanning from ∼33°N to ∼52°N. On the basis of sedimentary components, we divide them into three Zones (I, II, and III) spatially with distinct features. Sediments in Zone I (∼33°N–44°N) and Zone III (49.8°N–53°N) are dominated by clayey silt, and mainly consist of sand and silty sand in Zone II. The mean grain size of the sortable silt shows that the hydrodynamic condition in the study area is significantly stronger than that of the abyssal plain, especially at the water depth of 1,000–2,500 m. The CaCO3 contents in sediments above 4,000 m range from 20 to 84% but decrease sharply to less than 1.5% below 4,000 m, confirming that the water depth of 4,000 m is the carbonate compensation depth of the study area. Strong positive correlations between Al2O3 and Fe2O3, TiO2, MgO, and K2O (R > 0.9) in the bulk sediments indicate pronounced contributions of terrigenous materials from surrounding continent mass to the study area. Furthermore, the eolian dust makes contributions to the composition of bulk sediments as confirmed by rare earth elements. There is no significant correlation between grain size and major and minor elements, which indicates that the sedimentary grain size does not exert important effects on terrigenous components. There is significant negative δCe and positive δEu anomalies at all stations. The negative Ce anomaly mainly exists in carbonate-rich sediments, inheriting the signal of seawater. The positive Eu anomaly indicates widespread volcanism contributions to the study area from active volcanic islands arcs around the North Pacific. The relative contributions of terrestrial, volcanic, and biogenic materials vary with latitude and water depth in the study area.

scholarly journals Report on hydrozoans (Cnidaria), excluding Stylasteridae, from the Emperor Seamounts, western North Pacific Ocean

Zootaxa ◽  
2021 ◽  
Vol 4950 (2) ◽  
pp. 201-247
Author(s):  
DALE R. CALDER ◽  
LES WATLING
Keyword(s):  
Pacific Ocean ◽  
North Pacific ◽  
Western North Pacific ◽  
Cold Water ◽  
North Pacific Ocean ◽  
First Record ◽  
Western North Pacific Ocean ◽  
The North ◽  
Seamount Chain ◽  
The North Pacific

Fourteen species of hydroids, collected during August 2019 by ROV SuBastian of the Schmidt Ocean Institute, are reported from the Emperor Seamount chain in the western North Pacific Ocean. Two others, Candelabrum sp. and Eudendrium sp., were observed only on videos taken by the ROV. From collections and video observations, eight species of hydroids were found at Jingū Seamount, three at Yomei, Nintoku, and Annei seamounts, and one at Koko Seamount and Hess Rise. At Suiko and Godaigo seamounts, hydroids were seen in videos but they could not be identified. Latebrahydra schulzei, an endobiotic associate of the hexactinellid sponge Walteria flemmingii Schulze, 1886 from Annei Seamount and Hess Rise, is described as a new genus and species tentatively attributed to Hydractiniidae L. Agassiz, 1862. Another new species, Hydractinia galeai, is described from Jingū Seamount. Among its distinctive characters is a zooid termed a sellectozooid, likely serving in both food capture and defence. Hydroids examined from Yomei, Nintoku, and Jingū seamounts are elements of a cold-water fauna occurring in the North Pacific Boreal Bathyal province, while those of Annei and Koko seamounts, and Hess Rise, are part of the biota of the Central North Pacific Bathyal province. Hydroids identified as Bouillonia sp., from Nintoku Seamount, represent the first record of this predominantly deep water tubulariid genus in the North Pacific Ocean. Bonneviella superba Nutting, 1915, from Jingū Seamount, is reported for the first time outside the Aleutian Islands. Bonneviella cf. gracilis Fraser, 1939, known elsewhere only from Dease Strait in the western Canadian Arctic, was also collected on Jingū. In addition to hydroids, medusae of Ptychogastria polaris Allman, 1878 were observed on videos from Nintoku, Jingū, Annei, and Koko seamounts at depths between 2423–1422 m. An unidentified siphonophore was observed near bottom at 2282 m on Nintoku Seamount. 

Age of Kōko Seamount, Emperor Seamount chain

1973 ◽  
Vol 17 (2) ◽  
pp. 411-415 ◽  
Author(s):  
David A. Clague ◽  
G. Brent Dalrymple
Keyword(s):  
Seamount Chain ◽  
Emperor Seamount Chain

Crust and upper mantle structure along the flank of Kōko Seamount

1980 ◽  
Vol 70 (4) ◽  
pp. 1161-1169
Author(s):  
K. Furukawa ◽  
J. F. Gettrust ◽  
L. W. Kroenke ◽  
J. F. Campbell
Keyword(s):  
Upper Mantle ◽  
Seismic Refraction ◽  
Crustal Thickness ◽  
Mantle Structure ◽  
Crust And Upper Mantle ◽  
Velocity Gradients ◽  
Upper Mantle Structure ◽  
Hawaiian Ridge ◽  
Seamount Chain ◽  
Emperor Seamount Chain

abstract Inversion of an 80-km-long reversed seismic refraction profile near the northwestern flank of Kōko Seamount indicates that the crust adjacent to the southern end of the Emperor Seamount chain is approximately 9-km thick with no dip in the refracting horizons. These data require positive P-velocity gradients in the crust and upper mantle to fit the observed amplitudes. The crustal refractor P velocities and crustal thickness found are in general agreement with those found previously for the Emperor chain and near the Hawaiian Ridge. It is inferred from our data that the tectonic mechanism which created the Emperor and Hawaiian chains was highly localized.

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