Thorium isotope evidence for glacial–interglacial dust storminess and productivity in the North Pacific gyre

Chen, Tianyu; Zheng, Jianfan; Li, Tao; Shi, Xuefa; Robinson, Laura F.; Wang, Maoyu; Li, Gaojun; Ren, Xiaomin; Ji, Junfeng

doi:10.1016/j.gca.2023.01.007

Cited by 5 publications

(3 citation statements)

References 106 publications

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“…For example, the rates of glacial dust deposition are estimated to be two to five times higher than those during interglacial periods on a global scale (Abell et al., 2021; Maher et al., 2010; Winckler et al., 2008). For Asian dust emission and deposition, the fluxes of dust between glacial and interglacial periods exhibit substantial variability, with four‐ to fivefold changes recorded on the Chinese Loess Plateau (Liu et al., 2020) and two‐ to threefold changes observed at the southern margin of the Taklimakan Desert (Fang et al., 2020) and in the North Pacific Ocean (T. Chen et al., 2023). These pronounced orbital variations in the depositional flux of Mg‐rich carbonate dust inevitably yield periodic alterations in the Mg/Ca and Mg/Sr ratios of paleowater and authigenic carbonate in the downwind catchment, as demonstrated by the findings of this study.…”

Section: Discussionmentioning

confidence: 99%

A Hydrochemical Method for Identifying Orbital Imprints of Dust in Paleofluvial Sequences

Yan,

Yang,

Han

et al. 2024

Geophysical Research Letters

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Mineral dust plays an important role in Earth's climate system, yet it is difficult to identify dust imprints in paleofluvial sediments, especially on orbital timescales. Here, we present high‐resolution authigenic carbonate Ca–Mg–Sr compositions in a fluvial sequence under the transport pathway of Asian dust. The Mg/Ca, Sr/Ca, and Mg/Sr ratios exhibit distinct transitions in both secular trends and orbital cycles at ∼8 Ma. Before ∼8 Ma, given similar Mg and Sr partitioning behaviors during carbonate formation, hydroclimate changes yielded strong orbital signals in the Sr/Ca and Mg/Ca ratios but no detectable signals in the Mg/Sr ratios. After ∼8 Ma, given the strengthened input of Mg‐rich dust during cold‒dry periods, the Mg/Sr and Mg/Ca ratios clearly exhibited orbital signals, but the Sr/Ca ratio did not. Such transitions in carbonate composition corroborate the dust‐induced changes in fluvial hydrochemistry, offering an innovative methodology for detecting orbital dust cycles in paleofluvial systems.

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Section: Discussionmentioning

confidence: 99%

A Hydrochemical Method for Identifying Orbital Imprints of Dust in Paleofluvial Sequences

Yan,

Yang,

Han

et al. 2024

Geophysical Research Letters

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“…) was higher during glacials, at least over the last 200 kyr [40][41][42][43] (Supplementary Fig. 6e-g).…”

Section: Mechanism Driving the Nutrient Upwelling In The Subarctic Pa...mentioning

confidence: 94%

Ice sheet and precession controlled subarctic Pacific productivity and upwelling over the last 550,000 years

Yao,

Shi,

Yin

et al. 2024

Nat Commun

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The polar oceans play a vital role in regulating atmospheric CO2 concentrations (pCO2) during the Pleistocene glacial cycles. However, despite being the largest modern reservoir of respired carbon, the impact of the subarctic Pacific remains poorly understood due to limited records. Here, we present high-resolution, 230Th-normalized export productivity records from the subarctic northwestern Pacific covering the last five glacial cycles. Our records display pronounced, glacial-interglacial cyclicity superimposed with precessional-driven variability, with warm interglacial climate and high boreal summer insolation providing favorable conditions to sustain upwelling of nutrient-rich subsurface waters and hence increased export productivity. Our transient model simulations consistently show that ice sheets and to a lesser degree, precession are the main drivers that control the strength and latitudinal position of the westerlies. Enhanced upwelling of nutrient/carbon-rich water caused by the intensification and poleward migration of the northern westerlies during warmer climate intervals would have led to the release of previously sequestered CO2 from the subarctic Pacific to the atmosphere. Our results also highlight the significant role of the subarctic Pacific in modulating pCO2 changes during the Pleistocene climate cycles, especially on precession timescale ( ~ 20 kyr).

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“…During the period of growth that spans millions of years, e.g., [10], hydrogenous crusts absorb dissolved metals from the seawater, and studying REEs and metal isotopes makes it possible to reconstruct water masses [11][12][13][14][15]. In addition, volcanic activities, aeolian input, and cosmogenic matter also have fingerprints in the growth processes of these crusts [16,17], and metal/mineral changes can be correlated with the glacial-interglacial alternations [18][19][20][21][22]. For example, most REEs in hydrothermal crusts are associated with hydrous Fe oxides [23,24], while in hydrogenous crusts, REEs may be influenced by the competition between manganese and ferrous fractions [23,25].…”

Section: Introductionmentioning

confidence: 99%

Sr and Nd Isotopes in Mineral Fractions of Ferromanganese Crusts from the Northernmost Pacific

Mikhailik,

Vishnevskaya,

et al. 2023

JMSE

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A study of the isotopic compositions of neodymium and strontium in four mineral fractions of the hydrogenous ferromanganese crusts of the northernmost Pacific has been carried out for the first time. The relationship of the 87Sr/86Sr ratio and εNd value of the residual fraction in heterochronous layers of the ferromanganese crusts have shown that the sources of detrital matter are from rock weathering by the Yukon River, the Kuskokwim River, the Anadyr River and the rivers of Kamchatka. The amount of aluminosilicate impurity does not affect the isotopic compositions of the chemogenic (loosely bound, Mn oxides or manganese, hydrous Fe oxides or ferrous) fractions. The decreased εNd value in the ferrous fraction seems to be related to the presence of rare earth element (REE) phosphate complexes in seawater. The increase in those complexes is a consequence of melt waters entering the ocean during warming periods. Our data indicate that the carbonate REE complexes are not the dominant form of the REEs in the northernmost Pacific, which leads to the fact that the neodymium isotopic compositions of the manganese and ferrous fractions of hydrogenous ferromanganese crusts are different. A decrease in εNd value in the ferrous fraction may be a marker of a local increase in the surface water bioproductivity. Our data also show that the increase of the REE in the ferrous fraction relative to the manganese fraction does not reflect the participation of hydrothermal matter in the formation of mixed hydrogenous–hydrothermal crusts but is a consequence of an increase in the REE phosphate complexes.

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Thorium isotope evidence for glacial–interglacial dust storminess and productivity in the North Pacific gyre

Cited by 5 publications

References 106 publications

A Hydrochemical Method for Identifying Orbital Imprints of Dust in Paleofluvial Sequences

A Hydrochemical Method for Identifying Orbital Imprints of Dust in Paleofluvial Sequences

Ice sheet and precession controlled subarctic Pacific productivity and upwelling over the last 550,000 years

Sr and Nd Isotopes in Mineral Fractions of Ferromanganese Crusts from the Northernmost Pacific

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