Surface water productivity and sediment transport by Bering Strait throughflow in the Chukchi Shelf (the western Arctic Ocean) during the Holocene

Diverse paleoceanographic proxies from three sediment cores (GC12ex, JPC35, and JPC30) collected from the Chukchi Shelf north of the Bering Strait elucidate the Holocene paleoceanographic changes (surface water productivity and sediment transport) caused by the Bering Strait throughflow from the Bering Sea into the Chukchi Sea. Lithology of three sediment cores identified the same three units. Based on comparison and correlation to adjacent age-dated cores as well as AMS 14C dates of core GC12ex, the boundary between Unit 1 and Unit 2a is dated about 8500 cal. yr BP, and the boundary between Unit 2a and Unit 2b is also dated about 4500 cal. yr BP. Consistent down-core profiles of the geochemical and isotopic properties among the three cores differentiate the paleoceanographic conditions corresponding to lithologic units. Based on the biogenic opal, total organic carbon, and δ13C values, Unit 1 is characterized by low surface water marine productivity under relatively shallow water with weak transport of Bering Strait throughflow. Unit 2a shows a mixture of terrestrial and marine contributions, indicating the onset of increased marine surface water productivity after the main flooding (~11,500 cal. yr BP) of the Bering Strait by the Holocene sea-level rise. Unit 2b exhibits stable and enhanced marine biogenic opal production similar to the present-day oceanographic conditions. Such paleoceanographic changes were confirmed by the clay minerals (smectite, illite, kaolinite, and chlorite) and detrital isotopes (εNd and 87Sr/86Sr). Thus, the Bering Strait throughflow played an important role on surface water productivity and sediment deposition in the Chukchi Shelf in response to Holocene sea-level rise after the opening of the Bering Strait.

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Dinocysts as a Tool for Palaeoenvironmental Reconstruction in Vitória Bay, Brazil

Radiocarbon ◽

10.1017/rdc.2020.4 ◽

2020 ◽

Vol 62 (2) ◽

pp. 289-311

Author(s):

Alex da Silva de Freitas ◽

Javier Helenes Escamilla ◽

Cintia Ferreira Barreto ◽

Alex Cardoso Bastos ◽

Estefan Monteiro da Fonseca ◽

...

Keyword(s):

Sea Level ◽

Saline Water ◽

Sediment Cores ◽

Isotopic Analysis ◽

Southeastern Brazil ◽

Geochemical Data ◽

Estuarine System ◽

Marine Transgression ◽

The Holocene ◽

Energy Environment

ABSTRACTMicropaleontological and geochemical data were applied to sediments from southeastern Brazil to study the hydrodynamics associated with the Holocene sea level rise. Sediment cores were taken around Vitória Bay, examined for dinoflagellate cysts and subjected to isotopic analysis. The cyst assemblage mainly dominated by autotrophic species most notably O. centrocarpum, L. machaerophorum and T. vancampoae. The influence of the marine transgression and subsequent regression observed during the Holocene along the coast of Brazil could have initially favored the establishment of an oligotrophic and higher energy environment. The inflow of continental water from tributaries combined with a higher inflow of saline water into the estuarine system could have favored the establishment and subsequent deposition of the dinocysts.

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Coupled wind-forced controls of the Bering–Chukchi shelf circulation and the Bering Strait throughflow: Ekman transport, continental shelf waves, and variations of the Pacific–Arctic sea surface height gradient

Progress In Oceanography ◽

10.1016/j.pocean.2014.04.006 ◽

2014 ◽

Vol 125 ◽

pp. 40-61 ◽

Cited By ~ 91

Author(s):

Seth L. Danielson ◽

Thomas J. Weingartner ◽

Katherine S. Hedstrom ◽

Knut Aagaard ◽

Rebecca Woodgate ◽

...

Keyword(s):

Sea Surface ◽

Ekman Transport ◽

Bering Strait ◽

Shelf Circulation ◽

The Pacific ◽

Arctic Sea ◽

Bering Strait Throughflow ◽

Shelf Waves ◽

Continental Shelf Waves ◽

Chukchi Shelf

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An Integrated Latest Quaternary (Stage 3 to Present) Paleoclimatic and Paleoceanographic Record from Offshore Northern New Zealand

Quaternary Research ◽

10.1006/qres.1995.1073 ◽

1995 ◽

Vol 44 (2) ◽

pp. 283-293 ◽

Cited By ~ 64

Author(s):

Ian C. Wright ◽

Matt S. McGlone ◽

Campbell S. Nelson ◽

Brad J. Pillans

Keyword(s):

New Zealand ◽

Sea Level ◽

Vegetation History ◽

Sediment Cores ◽

Subsurface Water ◽

Deep Sea Sediment ◽

The Holocene ◽

The North ◽

Paleoclimatic Changes ◽

Stage 4

AbstractPaleoceanographic and onshore paleoclimatic changes during the last 59,000 yr are established from three deep-sea sediment cores off northeast New Zealand using an integrated log of sediment texture, CaCO3 content, palynology, and planktonic and benthic foraminiferal δ18O and δ13C data, together with dated silicic tephras. These records from the isotopic stage 4-3 boundary to the present record northern New Zealand vegetation history, changes in a subsidiary equatorward flow of Circumpolar Deep Water, and sea-surface temperatures (SSTs) for subtropical water (STW) between latitudes 36°42′ and 35°51′S. Relative to the Holocene, isotopically derived SSTs record average changes of +2°C, -2°C, and -2°C for the 59,000-43,000, 43,000-24,000, and 24,000-12,000 yr time slices, respectively. The apparent +2°C warming for the 59,000-43,000 yr period is interpreted to reflect changes in the dominant depth habitat of Globigerina bulloides in response to upwelling. A -2°C cooling of SSTs during isotope stage 2 is interpreted, in part, to reflect upwelling of cool subsurface water resulting from strong and persistent westerly airflow across New Zealand, with the concomitant enhanced surface-water production of CaCO3. Onshore, vegetation consistent with these changes are recorded, with full conifer-hardwood forest prior to 43,000 yr, followed by a change to vegetation implying cooler and drier conditions between 43,000 and 12,000 yr, and a subsequent return to full forest during the Holocene. The sequence of biopelagic and hemipelagic sedimentation observed within these cores reflect oscillation of sea level about a threshold eustatic level that controls the transport of terrigenous detritus offshore. Local variations and interplay of the regional oceanography and morphology and tectonism of the continental shelf will dictate that, relative to present sea level, this threshold eustatic sea level will vary in depth, and hence age, along a continental margin. Data from the New Zealand region reveal an extremely steep meridional thermal gradient across the southern and central New Zealand region during the last glaciation with minor cooling of STW to the north, apart from localized nearshore upwelling zones, but pronounced cooling of subantarctic water to the south of the subtropical convergence zone.

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Timing and Mechanisms of the Formation of the Dark Layers in the Sea of Japan During the Last 40 kyr

Frontiers in Earth Science ◽

10.3389/feart.2021.647495 ◽

2021 ◽

Vol 9 ◽

Author(s):

S. Gorbarenko ◽

X. Shi ◽

A. Bosin ◽

Y. Liu ◽

A. Artemova ◽

...

Keyword(s):

Surface Water ◽

Sea Level ◽

Sea Of Japan ◽

Asian Monsoon ◽

East Asian Monsoon ◽

East Asian ◽

The Sea Of Japan ◽

The Holocene ◽

Water Stratification ◽

Global Sea Level

The marginal location of the Sea of Japan and its constrained water exchange with the western Pacific make this sea a subtle subject for the investigation of orbital and suborbital climate changes. However, the response of this unique basin to the climate and sea level changes at the end of the last glaciation and deglaciation and during the Holocene is not fully understood. We provided detailed reconstructions of the dark layers including the timing and mechanisms responsible for their formation, during the last 40°kyr, based on the multiproxy correlation of three cores from the northern and central parts of the sea with well-dated δ18O records of the Greenland ice and China cave stalagmites. High resolution color photo lightness, the conventional color parameters L* and b*, AMS 14C data, chlorin and carbonate calcium content and pollen climate parameters allowed the correlation of the DLs of these cores with Greenland interstadials (GI), Heinrich stadials (HS) and summer East Asian monsoon intensity. DLs 9, 8, 7, and 6, formed after Heinrich stadials 4 (38.5–39.5°ka), were triggered by GIs 8, 7, 6 and 5, coeval with the intensification of the East Asian summer monsoon and the increase of surface water stratification and productivity. The long-lasting GI 8, accompanied by significant climate warming, led to the formation of the more intense DL 9. The accumulation of DL five was forced by a rapid global sea level fall, coeval with cold HS 3, due to the decrease of saline Tsushima Current water input into the sea, increased surface water stratification and a drop in deep water ventilation. DL four was probably launched by GI 3 and summer East Asian monsoon intensification. Further falls in global sea level during the last glacial maximum led to the formation of DLs 3 and 2 during the periods 27.0–24.2°ka and 23.5–17.0°ka, respectively. DL 1 was associated with significant summer East Asian monsoon intensification and environmental warming at the onset of the Holocene.

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Assessing controls on organic matter enrichments in hemipelagic homogenous marls of the Cretaceous Vocontian Basin (France): an unexpected variability observed from multiple organic-rich levels

BSGF - Earth Sciences Bulletin ◽

10.1051/bsgf/2022001 ◽

2022 ◽

Author(s):

Alexis Caillaud ◽

Melesio Quijada ◽

Stephan R. Hlohowskyj ◽

Anthony Chappaz ◽

Viviane Bout-Roumazeilles ◽

...

Keyword(s):

Organic Matter ◽

Surface Water ◽

Sea Level ◽

Water Productivity ◽

The Other ◽

Redox Conditions ◽

Accumulation Rates ◽

High Productivity ◽

Anoxic Events ◽

Parameter Approach

The Marnes Bleues Formation from the Vocontian Basin (Southeastern France) shows many organic rich levels, some concomitant to oceanic anoxic events OAE1a and OAE1b. These organic-rich levels are scattered through a thick homogeneous succession of marls, poor in organic matter (OM). Through a multi-parameter approach, the organic-rich levels from the Aptian-Albian were characterized. Our results show that all OM-rich levels exhibit variable characteristics, such as OM nature (marine vs. continental), sedimentation and accumulation rates, redox conditions, surface-water productivity and relative sea level, but they all show low to modest enrichments in OM. Furthermore, all the levels share in common the fact that they formed under conditions of normal to low productivity and oxic to suboxic conditions. Thus, our results strongly suggest that, in the absence of high productivity and anoxic bottom conditions, the other factors reputed to favor OM accumulation only led to sporadic and low enrichments in organic contents. It is as if such factors could only enhance OM accumulation but could not induce it alone. What was true for the Vocontian Basin may be extended to other settings, regardless of their time of deposition or location.

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Terrestrial and aquatic palynomorphs in Holocene sediments from the Chukchi–Alaskan margin, western Arctic Ocean: Implications for the history of marine circulation and climatic environments

The Holocene ◽

10.1177/0959683616678459 ◽

2016 ◽

Vol 27 (7) ◽

pp. 976-986 ◽

Cited By ~ 2

Author(s):

So-Young Kim ◽

Leonid Polyak ◽

Irina Delusina

Keyword(s):

Late Holocene ◽

Vegetation History ◽

Climatic Factors ◽

Chukchi Sea ◽

Sediment Cores ◽

Depositional Environments ◽

Chukchi Peninsula ◽

Bering Strait ◽

The Holocene ◽

Paleoclimatic Changes

Two sediment cores from the Chukchi Sea margin north of Alaska were analyzed for palynological composition including terrestrial and aquatic palynomorphs. Based on 13 radiocarbon ages, the investigated sedimentary record represents most of the Holocene with a century to multidecadal age resolution. Three palynological zones were discriminated based on the abundance of major palynomorph groups (terrestrial and freshwater palynomorphs and dinoflagellate cysts) and composition of spore and pollen assemblages. They are interpreted in terms of depositional and paleoclimatic changes including predominance of redeposition by meltwater or sea ice in the early-Holocene, a strong input of contemporaneous material related to Pacific water advection culminating after ca. 6000 yr BP, and more subtle changes in the late-Holocene. It is concluded that depositional environments, such as current transportation and mixing, have an overall major control on palynomorph distribution. The climatic factors may have also played an important role in palynomorph abundance and composition, especially in the middle- to late-Holocene, when circulation changes were less dramatic than during the flooding of the Bering Strait and the shallow Chukchi Sea shelf. Comprehending these linkages requires a better knowledge of the Holocene vegetation history in the coastal areas of Alaska and Chukchi Peninsula.

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CORRELATION OF THE BLACK, MARMARA AND AEGEAN SEAS DURING THE HOLOCENE

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.21610/conferencearticle_58b4315c686d6 ◽

2017 ◽

Author(s):

Nikolay Esin ◽

Vladimir Ocherednik ◽

Vladimir Ocherednik

Keyword(s):

Mathematical Model ◽

Sea Level ◽

Black Sea ◽

Aegean Sea ◽

The Black Sea ◽

Sea Level Changes ◽

The Holocene

A mathematical model describing the change in the Black Sea level depending on the Aegean Sea level changes is presented in the article. Calculations have shown that the level of the Black Sea has been repeating the course of the Aegean Sea level for the last at least 6,000 years. And the level of the Black Sea above the Aegean Sea level in the tens of centimeters for this period of time.

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