A reassessment of Nd-isotopes and clay minerals as tracers of the Holocene Pacific water flux through Bering Strait

AbstractTwo soil profile sequences on paragneiss debris in the Val di Rabbi (Northern Italy) along an altitude gradient ranging from 1200 to 2400 m a.s.l. were studied to evaluate the effect of aspect on the weathering of clay minerals. All the soils had a coarse structure, a sandy texture and a low pH. Greater weathering intensities of clay-sized phyllosilicates (greater content of smectites) were observed in soils on the north-facing slope. On the south-facing slope, smectite was found only in the surface horizon of the soil profile at the highest altitude. Hot citrate treatment of north-facing soils revealed the presence of low-charged 2:1 clay minerals, the expansion of which was hindered in the untreated state by interlayered polymers. However, the hot citrate treatment encountered some problems with the samples of the south-facing soils: as confirmed by Fourier transform infrared spectroscopy, the hot citrate treatment was unable to remove all interlayer Al polymers. The 2:1 phyllosilicates were not expanded by ethylene glycol solvation in several samples, although thermogravimetric analyses indicated the presence of clay minerals with interlayer H2O. At the same time, the collapse of clay minerals to 1.0 nm following K-saturation was evident. Theoretically, this should indicate that 2:1 phyllosilicates had no evident substitution of trioctahedral cations (Mg2+, Fe2+) by dioctahedral cations (Al3+ and Fe3+). X-ray diffraction analysis of the d060 region and determination of the layer charge of clay minerals by the long-chain (C18) alkylammonium ion, however, did not confirm this. A transformation from trioctahedral to dioctahedral species was observed and low-charge clay minerals (ξ ~0.30) were identified in the surface horizons of the south-facing sites. In the south-facing soils, the podzolization process was less pronounced because of a lower water flux through the soil and probably less complexing organic molecules that would remove the interlayer polymers. Besides the eluviation process, clay minerals underwent a process of ionic substitutions in the octahedral sheet that led to the reduction of the layer charge. This process was more obvious in the north-facing sites.

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

The Holocene ◽

10.1177/0959683617744265 ◽

2017 ◽

Vol 28 (5) ◽

pp. 814-826 ◽

Cited By ~ 2

Author(s):

Boo-Keun Khim ◽

Mi Jung Lee ◽

Hyen Goo Cho ◽

Kwangkyu Park

Keyword(s):

Surface Water ◽

Sediment Transport ◽

Sea Level ◽

Water Productivity ◽

Sediment Cores ◽

Bering Strait ◽

Biogenic Opal ◽

The Holocene ◽

Bering Strait Throughflow ◽

Chukchi Shelf

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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Spatial and temporal distributions of clay minerals in mud deposits on the inner shelf of the East China Sea: Implications for paleoenvironmental changes in the Holocene

Quaternary International ◽

10.1016/j.quaint.2014.07.016 ◽

2014 ◽

Vol 349 ◽

pp. 270-279 ◽

Cited By ~ 35

Author(s):

Shengfa Liu ◽

Xuefa Shi ◽

Xisheng Fang ◽

Yanguang Dou ◽

Yanguang Liu ◽

...

Keyword(s):

Clay Minerals ◽

East China Sea ◽

East China ◽

The East China Sea ◽

Inner Shelf ◽

The Holocene ◽

China Sea ◽

Paleoenvironmental Changes ◽

Spatial And Temporal Distributions

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Holocene dynamics in the Bering Strait inflow to the Arctic and the Beaufort Gyre circulation based on sedimentary records from the Chukchi Sea

10.5194/cp-2017-58 ◽

2017 ◽

Cited By ~ 1

Author(s):

Masanobu Yamamoto ◽

Seung-Il Nam ◽

Leonid Polyak ◽

Daisuke Kobayashi ◽

Kenta Suzuki ◽

...

Keyword(s):

Sea Ice ◽

Chukchi Sea ◽

Arctic Sea Ice ◽

The Arctic ◽

Circulation System ◽

Bering Strait ◽

The Holocene ◽

Middle Holocene ◽

Beaufort Gyre

Abstract. The Beaufort Gyre (BG) and the Bering Strait inflow (BSI) are important elements of the Arctic Ocean circulation system and major controls on the distribution of Arctic sea ice. We report records of the quartz/feldspar and chlorite/illite ratios in three sediment cores from the northern Chukchi Sea providing insights into the long-term dynamics of the BG circulation and the BSI during the Holocene. The quartz/feldspar ratio, a proxy of the BG strength, gradually decreased during the Holocene, suggesting a long-term decline in the BG strength, consistent with orbitally-controlled decrease in summer insolation. We suppose that the BG rotation weakened as a result of increasing stability of sea-ice cover at the margins of the Canada Basin, driven by decreasing insolation. Millennial to multi-centennial variability in the quartz/feldspar ratio (the BG circulation) is consistent with fluctuations in solar irradiance, suggesting that solar activity affected the BG strength on these timescales. The BSI approximated by the chlorite/illite record shows intensified flow from the Bering Sea to the Arctic during the middle Holocene, which is attributed primarily to the effect of an overall weaker Aleutian Low. The middle Holocene intensification of the BSI was associated with decrease in sea ice concentrations and increase in marine production, as indicated by biomarker concentrations, suggesting an influence of the BSI on sea ice distribution and biological production in the Chukchi Sea.

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On soil genesis in temperate humid climate. VIII. The formation of a "udalfic" eutrochrepi.

Netherlands Journal of Agricultural Science ◽

10.18174/njas.v18i3.17344 ◽

1970 ◽

Vol 18 (3) ◽

pp. 207-214 ◽

Cited By ~ 1

Author(s):

J. Van Schuylenborgh ◽

S. Slager ◽

A.G. Jongmans

Keyword(s):

Biological Activity ◽

Clay Minerals ◽

Redox Processes ◽

Humid Climate ◽

Soil Genesis ◽

Fe Oxide ◽

The Holocene ◽

Differential Movement ◽

The Difference ◽

Soil Forming Processes

The active soil-forming processes occurring in a Holocene alluvial deposit were: the formation, along voids, of illuvial cutans consisting of clay minerals, Fe oxide and fine matric components (matriferriargillans), differential movement of clay minerals, kaolinite being most mobile; partial transformation of smectites into kandites; disturbance of cutans by biological activity resulting in the formation of papules; redox processes leading to the formation of micro-segregation of Fe oxide. The difference in character and location of matriferriargillans and ferriargillans is discussed. The former are thought to have been synthesized in the Holocene period and the latter in Pleistocene times. The soil is classifiable as a dystric eutrochrept, but as plasma movement generally occurs only in "dystric" (decalcified) material, the soil could be classified as a "udalfic" eutrochrept. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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The use of clay minerals and microfossils in palaeoenvironmental reconstructions: The Holocene littoral strand of Las Nuevas (Doñana National Park) SW Spain

Clay Minerals ◽

10.1180/0009855023710020 ◽

2002 ◽

Vol 37 (1) ◽

pp. 93-103 ◽

Cited By ~ 10

Author(s):

M. I. Carretero ◽

F. Ruiz ◽

A. Rodríguez-Ramírez ◽

L. Cáceres ◽

J. Rodríguez Vidal ◽

...

Keyword(s):

Clay Minerals ◽

National Park ◽

Clay Mineralogy ◽

Crystallinity Index ◽

Second Step ◽

Doñana National Park ◽

The Holocene ◽

Coastal Species ◽

Juvenile Stages ◽

Shallow Lagoon

AbstractThree steps have been established during the Holocene formation of the bar-built estuary of Las Nuevas (Doñana National Park, Spain), on the basis of the clay mineralogy variations and the palaeontological record. The first step is characterized by the presence of ostracodes and homogeneous quantities of clay minerals (17–20% illite, 25–29% smectites), values of smectite (0.64–0.70) and illite (0.60–0.70) crystallinity indexes, and the ratio of AlVI/(FeVI + MgVI) in illite (0.46–0.47). This zone is interpreted as a very shallow lagoon with euryhaline conditions. The presence of roots, the progressive disappearance of foraminifers and an increase in the smectite content (up to 35%) define the second step. A salt-marsh environment with low-energy hydrodynamic conditions is deduced for this zone. The third step is characterized by an increase in illite content (up to 35%), and a decrease of the smectite content (up to 21%). The smectite crystallinity index decreased to 0.38, whereas the illite ratio AlVI/(FeVI + MgVI) decreased to 0.36. In this zone, the ostracode assemblage contains numerous juvenile stages of coastal species coinciding with lumachelle accumulations of the estuarine bivalves, abundant foraminifers and the presence of charophytes. This zone represents a strong marine input, probably caused by storms.

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Pacific Water Pathways through the Arctic Ocean

10.5194/egusphere-egu2020-15898 ◽

2020 ◽

Author(s):

Paul A. Dodd ◽

Tore Hattermann ◽

Michael Karcher ◽

Frank Kauker ◽

Colin Stedmon

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Large Scale ◽

The Arctic ◽

Fram Strait ◽

Bering Strait ◽

Wind Fields ◽

Pacific Water ◽

Back Trajectories ◽

The Arctic Ocean

The volume, characteristics and sources of freshwater circulating in the Arctic Ocean vary in time and are expected to change under a declining sea ice cover, influencing the physical environment and Arctic ecosystem. Relatively fresh (S = 32) Pacific Water, which enters the Arctic Ocean via the Bering Strait makes up a significant part of the liquid freshwater exiting the Arctic Ocean through Fram Strait. If transported to the Nordic Seas and North Atlantic via the East- and West Greenland Currents freshwater from the Pacific could have an effect on convection and dense water formation in those regions.More than 30 repeated sections of nutrient measurements have been collected across Fram Strait between 1980 and 2019. The fraction of Pacific Water along these repeated sections can be estimated from the ratio of nitrate to phosphate. The time-series of repeated Fram Strait sections indicates that the fraction of Pacific Water passing out of the Arctic Ocean has changed significantly over the last 30 years. Pacific water fractions remained high from 1980 to 1998, but in 1999 Pacific water almost disappeared from Fram Strait, reappearing from 2011 to 2012, when there was a peak in freshwater export though Fram Strait.Several hypotheses suggest how variations in the large-scale atmospheric circulation over the Arctic Ocean may influence the transport and pathways of Pacific Water. We show how anomalies in reanalysis wind fields are associated with the reappearance of Pacific Water in Fram Strait in recent years. Repeated sections across Fram Strait are compared with sea ice back-trajectories in the Polar Pathfinder 4 product and a simulated Pacific Water tracer in the NAOSIM numerical model to investigate likely Pacific water pathways through the Arctic Ocean and upstream drivers of changes observed in Fram Strait.

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Spatial and temporal distributions of clay minerals in mud deposits on the inner shelf of the East China Sea: Implications for paleoenvironmental changes in the Holocene

10.5194/egusphere-egu2020-8782 ◽

2020 ◽

Author(s):

Shengfa Liu ◽

Xuefa Shi ◽

Xisheng Fang ◽

Yanguang Dou ◽

Yanguang Liu ◽

...

Keyword(s):

Sea Level ◽

Clay Minerals ◽

East China Sea ◽

Clay Mineral ◽

East China ◽

The East China Sea ◽

Inner Shelf ◽

Research Project ◽

The Holocene ◽

Fine Sediments

We present a paleoclimatic reconstruction for the Holocene by clay mineral analyses of sediments from core MZ02 retrieved from the mud area of the inner continental shelf of the East China Sea (ECS). The clay minerals mainly consist of illite (66%-79%) and chlorite (12%-19%), with minor kaolinite (7%-13%) and smectite (0-6%). Provenance analysis suggests that the illite-dominated clay minerals were derived mainly from the detrital outputs of the Changjiang, Minjiang, and small rivers from Taiwan Island. Our study indicates that the sea level rise since the last glacial, the strength of the Taiwan Warm Current (TWC) and Chinese Coastal Current (CCC) have controlled the dispersal and deposition of clay minerals on the ECS, that in turn determined the clay mineral compositions in the core sediments. During 13,000-9500 BP, due to the lower sea level and shorter distance between these three estuaries and core MZ02, fine sediments on the inner shelf of the ECS were primarily supplied by mixed provenances from the Changjiang, Taiwanese, and Minjiang rivers. During the early Holocene (9500-6200 BP), stronger sediment reworking and erosion at the shelf edge was responsible for the increased lateral transport of fine sediments in the ECS, which lead to a dominance of the sediment source from the Changjiang, while the Taiwanese and Minjiang rivers only provided minor components of detrital sediment to the shelf. Increased strength of TWC might have played an important role in the sediment dispersal and deposition on the inner shelf of the ECS during 6200-2400 BP, with a dominance of more than 60% sediments transported from Taiwanese rivers. Furthermore, our study implies that the Asian monsoon and the weakening of TWC were linked to the abrupt increase of Changjiang and Minjiang derived terrigenous detritus materials since 2400 BP.&#160;AcknowledgmentsThis work was supported by National Nature Science Foundation of China (No.41106063), Science and Technology Basic Special Program of China (No.2008FY220300), Marine Public Welfare Research Project of China (No.200805063), China Postdoctoral Science Foundation (No.20100481304) and Coastal Investigation and Research Project of China (No. 908-01-CJ12).

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Holocene dynamics in the Bering Strait inflow to the Arctic and the Beaufort Gyre circulation based on sedimentary records from the Chukchi Sea

Climate of the Past ◽

10.5194/cp-13-1111-2017 ◽

2017 ◽

Vol 13 (9) ◽

pp. 1111-1127 ◽

Cited By ~ 12

Author(s):

Masanobu Yamamoto ◽

Seung-Il Nam ◽

Leonid Polyak ◽

Daisuke Kobayashi ◽

Kenta Suzuki ◽

...

Keyword(s):

Solar Activity ◽

Sea Ice ◽

Chukchi Sea ◽

Arctic Sea Ice ◽

The Arctic ◽

Circulation System ◽

Bering Strait ◽

The Holocene ◽

Beaufort Gyre

Abstract. The Beaufort Gyre (BG) and the Bering Strait inflow (BSI) are important elements of the Arctic Ocean circulation system and major controls on the distribution of Arctic sea ice. We report records of the quartz ∕ feldspar and chlorite ∕ illite ratios in three sediment cores from the northern Chukchi Sea, providing insights into the long-term dynamics of the BG circulation and the BSI during the Holocene. The quartz ∕ feldspar ratio, interpreted as a proxy of the BG strength, gradually decreased during the Holocene, suggesting a long-term decline in the BG strength, consistent with an orbitally controlled decrease in summer insolation. We propose that the BG rotation weakened as a result of the increasing stability of sea-ice cover at the margins of the Canada Basin, driven by decreasing insolation. Millennial to multi-centennial variability in the quartz ∕ feldspar ratio (the BG circulation) is consistent with fluctuations in solar irradiance, suggesting that solar activity affected the BG strength on these timescales. The BSI approximation by the chlorite ∕ illite record, despite a considerable geographic variability, consistently shows intensified flow from the Bering Sea to the Arctic during the middle Holocene, which is attributed primarily to the effect of higher atmospheric pressure over the Aleutian Basin. The intensified BSI was associated with decrease in sea-ice concentrations and increase in marine production, as indicated by biomarker concentrations, suggesting a major influence of the BSI on sea-ice and biological conditions in the Chukchi Sea. Multi-century to millennial fluctuations, presumably controlled by solar activity, were also identified in a proxy-based BSI record characterized by the highest age resolution.

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