Impact of climate change on the magnetic mineral assemblage in marine sediments from Izu rear arc, NW Pacific Ocean, over the last 1 Myr

Kars, Myriam; Musgrave, R. J.; Kodama, Kazuto; Jonas, A.-S.; Bordiga, Manuela; Ruebsam, Wolfgang; Mleneck‐Vautravers, Maryline J.; Bauersachs, Thorsten

doi:10.1016/j.palaeo.2017.05.016

Cited by 19 publications

(28 citation statements)

References 86 publications

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“…This large and rapid geochemical variability is evident in our samples, in the NGR‐based data (Figure ), and in the logging data (Tamura et al, 2015). We discovered orbital periodicities in the total NGR intensity in the uppermost 100 m (not shown), as did Kars et al (). High NGR is associated with glacial stages.…”

Section: Discussionsupporting

confidence: 88%

Tuffaceous Mud is a Volumetrically Important Volcaniclastic Facies of Submarine Arc Volcanism and Record of Climate Change

Gill

Bongiolo

Miyazaki

et al. 2018

Geochem Geophys Geosyst

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The inorganic portion of tuffaceous mud and mudstone in an oceanic island arc can be mostly volcanic in origin. Consequently, a large volume of submarine volcaniclastic material is as extremely fine‐grained as products of subaerial eruptions (<100 µm). Using results of IODP Expedition 350 in the Izu rear arc, we show that such material can accumulate at high rates (12–20 cm/k.y.) within 13 km of the nearest seamount summit and scores of km behind the volcanic front. The geochemistry of bulk, acid‐leached mud, and its discrete vitriclasts, shows that >75% of the mud is volcanic, and that most of it was derived from proximal rear arc volcanic sources. It faithfully preserves integrated igneous geochemical information about arc evolution in much the same way that terrigenous shales track the evolution of continental crust. In addition, their high sedimentation rate enables high resolution study of climate cycles, including the effects of Pleistocene glaciation on the behavior of the Kuroshio Current in the Shikoku Basin south of Japan.

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Section: Discussionsupporting

confidence: 88%

Tuffaceous Mud is a Volumetrically Important Volcaniclastic Facies of Submarine Arc Volcanism and Record of Climate Change

Gill

Bongiolo

Miyazaki

et al. 2018

Geochem Geophys Geosyst

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“…S −0.3T is restricted to values >0.945 through the whole studied sequence (Figure ), which indicates that ferrimagnets dominate the magnetization of all samples. Samples with scattered low values <0.96 occur in the upper 200 mbsf of Unit I, which corresponds to the interval studied in detail by Kars et al (), who inferred the presence of detrital hematite in the continental hemipelagic mud component from the presence of a high‐coercivity fraction. However, neither that study, nor the present work, identified Morin transitions within the upper part of Unit I, which suggests that any hematite present is fine‐grained (Özdemir et al, ) or contributes substantially less to the net magnetization than the ferrimagnetic components.…”

Section: Discussionsupporting

confidence: 72%

“…Detrital magnetic mineral input to the tuffaceous mud that dominates the upper 1,300 mbsf of the studied sequence (Units I, II, and V) is dominated by magnetite, which reflects its volcanic arc source. Magnetotactic bacteria are at most a minor contributor to the magnetic mineral assemblage, although high‐resolution FORC analyses in a detailed study of samples from the upper 100 m of Hole U1437B (Kars et al, ) do display a weak central ridge, suggesting a small biogenic component. RTSIRM results also indicate that surface oxidation of magnetite is limited in the muds, although it may increase (or Ti content may increase) in the volcaniclastic‐dominated units in the deeper part of the sequence.…”

Section: Discussionmentioning

confidence: 99%

Progressive and Punctuated Magnetic Mineral Diagenesis: The Rock Magnetic Record of Multiple Fluid Inputs and Progressive Pyritization in a Volcano‐Bounded Basin, IODP Site U1437, Izu Rear Arc

2019

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International Ocean Discovery Program (IODP) Site U1437 recovered an 1,800‐m‐long sediment sequence in a volcano‐bounded basin on the Izu rear arc. Pore fluid studies revealed a pattern of repeated fluid inputs, fluid diffusion, and methane and ethane accumulations, which represent “fluid anomalies” that disturb the fluid profiles. First‐order reversal curve analysis, magnetic hysteresis, saturation isothermal remanent magnetization, and low‐temperature remanence cycling reveal a detrital input dominated by vortex‐state and multidomain magnetite, which passes through an initial stage of partial magnetite dissolution and greigite authigenesis in the upper few tens of meters. Progressive magnetic mineral diagenesis comprises the continued loss of fine‐grained magnetite and gradual pyritization of greigite and produces a background logarithmic decrease in saturation isothermal remanent magnetization normalized by magnetic susceptibility. This process implies a continuing slow supply of S2− to depths >1,500 m. Thermally driven diagenesis, which would cause extensive loss of greigite at these depths, does not appear to be significant here. Multidomain magnetite grains dominate the magnetic mineralogy in the deepest part of the sequence, but some single‐domain magnetite survives as inclusions in silicates. Fluid anomalies representing sulfate influx drive locally renewed greigite authigenesis, as do methane and ethane accumulations. In some cases, where methane is accompanied by H2S (“sour gas”), fine‐grained greigite is converted to pyrite. We term these multiple episodes of enhanced magnetic mineral alteration “punctuated magnetic mineral diagenesis.” Despite both progressive and punctuated magnetic mineral diagenesis, enough depositional remanence survives to allow recognition of the magnetostratigraphy to 1,320 m below seafloor.

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“…In the North Pacific, rock magnetic studies have shown a link between variability in magnetic properties and glacial‐interglacial cyclicity and explained the variation as a result of an increase in detrital input during glacials (Doh et al, ; Kars et al, ; Yamazaki & Ioka, ). Over glacial‐interglacial climatic cycles, eolian dust originating mostly from the Taklimakan Desert (TK) in China has accumulated in the North Pacific in varying amounts (Serno et al, ; T. L. Zhao et al, ).…”

Section: Introductionmentioning

confidence: 99%

Magnetic Properties of Deep‐Sea Sediments From the North Pacific: A Proxy of Glacial Deep‐Water Ventilation

Shin

Seo

et al. 2018

Geochem Geophys Geosyst

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The magnetic properties of deep‐sea sediments in the North Pacific vary in sync with glacial‐interglacial climatic changes and have thus been considered as a paleoclimate indicator. However, the causes of these variations in magnetic properties, including the concentration, grain size, and mineralogy of magnetic minerals, remain poorly understood. Here we investigate the magnetic properties of deep‐sea sediments recovered from the Shatsky Rise in the North Pacific to investigate the cause of the variability associated with glacial‐interglacial cycles. Compared to the potential sediment provenances, the interglacial‐stage and more than half of the glacial‐stage sediments reveal magnetic mineralogical properties (S ratio and L ratio) of the Gobi and Taklimakan deserts, probably indicating dust from the both sources. During glacials, an abrupt decrease in the concentration of magnetic minerals is associated with increases in the average grain size and in the proportion of hematite relative to magnetite. The changes during glacials are mostly a result of dissolutions of magnetite by exposure to ambient ocean environments after deposition. Both magnetic and geochemical proxies validate that poor ventilation of the glacial deep waters in the North Pacific possibly induced iron‐reducing conditions. With comprehensive compilation with the S‐ratio data in the North Pacific sediments, our result indicates that the poorly ventilated deep waters reached up to water depths of ~2,500 m during glacials.

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Impact of climate change on the magnetic mineral assemblage in marine sediments from Izu rear arc, NW Pacific Ocean, over the last 1 Myr

Cited by 19 publications

References 86 publications

Tuffaceous Mud is a Volumetrically Important Volcaniclastic Facies of Submarine Arc Volcanism and Record of Climate Change

Tuffaceous Mud is a Volumetrically Important Volcaniclastic Facies of Submarine Arc Volcanism and Record of Climate Change

Progressive and Punctuated Magnetic Mineral Diagenesis: The Rock Magnetic Record of Multiple Fluid Inputs and Progressive Pyritization in a Volcano‐Bounded Basin, IODP Site U1437, Izu Rear Arc

Magnetic Properties of Deep‐Sea Sediments From the North Pacific: A Proxy of Glacial Deep‐Water Ventilation

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