Site U1437

Tamura, Yoshihiko; Busby, Cathy J.; Blum, Peter; Guèrin, G.; Andrews, Graham; Barker, Abigail; Berger, Julien; Bongiolo, Everton Marques; Bordiga, Manuela; DeBari, S. M.; Gill, Jim; Hamelin, C.; Jia, Jihui; John, Eleanor H.; Jonas, A.-S.; Jutzeler, Martin; Kars, Myriam; Kita, Zachary A.; Konrad, Kevin; Mahony, Susan H; Martini, Michelangelo; Miyazaki, Takashi; Musgrave, R. J.; Nascimento, Daniel Ferreira do; Nichols, A. R.; Ribeiro, Julia M.; Sato, Tadasu; Schindlbeck, Julie; Schmitt, Axel K.; Straub, Susanne M.; Vautravers, M. J.; Yang, Y. and

doi:10.14379/iodp.proc.350.104.2015

Cited by 13 publications

(71 citation statements)

References 104 publications

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“…Sedimentation rates across Units I through V varied between 98 and 259 m/My, but mostly did not deviate far from a mean of about 165 m/My (Tamura et al, ), so log (SIRM/κ) is also approximately linear with respect to depositional age. Such a relationship suggests a slow pyritization process continuing at a background rate long after early magnetic diagenesis is completed.…”

Section: Discussionmentioning

confidence: 92%

“…Location, core recovery, stratigraphy, age model, and magnetostratigraphy of Site U1437 (from Tamura et al, ). Core recovery columns: black = recovered interval, white = unrecovered interval, gray = drilled without coring.…”

Section: Introductionmentioning

confidence: 99%

“…Calcareous nannofossils and foraminifers define a series of biostratigraphic datums that extend from the seafloor to 867 mbsf, with the oldest datum at 5.28 Ma (Tamura et al, ). Magnetic reversal datums agree closely with biostratigraphic ages and extend the age record to 1,303 mbsf, near the base of the mudstone‐dominated sequence where the oldest polarity datum recognized was the top of Chron C4An (8.77 Ma).…”

Section: Introductionmentioning

confidence: 99%

“…What sets Site U1437 aside from other marine sediment sequences which have been the subject of magnetic diagenesis studies (e.g., Channell & Hawthorne, ; Garming et al, ; Kawamura et al, ; Musgrave et al, ) is the complexity of its pore fluid profile (Figure and supporting information Figure S1). Interstitial water profiles of sulfate and of Li and other cations show local peaks that were interpreted as evidence for local influx of fluid transported laterally along fracture systems or horizons of enhanced permeability (Tamura et al, ). These fluid inputs are either currently active or recent enough to have preserved a diffusion profile.…”

Section: Introductionmentioning

confidence: 99%

“…Methane, which is present in markedly higher concentrations in the interval from 750 to 1,035 mbsf, may have been locally sourced, but the correlation between total organic carbon contents and gas concentrations is poor (Kars et al, ), favoring gas migration. Ethane appeared above detection limits for the first time in the first core below an interpreted fault at the break between the bottom of Hole U1437D and the beginning of coring at the same subbottom depth in Hole U1437E (Musgrave & Kars, ; Tamura et al, ). Contrasting ethane abundance in the hanging and footwalls of this fault are consistent with gas migration.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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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Recognizing magnetostratigraphy in overprinted and altered marine sediments: Challenges and solutions from IODP Site U1437

Musgrave

Kars

2016

Geochem Geophys Geosyst

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Core disturbance, drilling overprints, postdepositional acquisition of remanence, authigenic growth of magnetic iron sulfides, and alteration all contribute challenges to recognizing the primary magnetostratigraphy in marine sediments. We address these issues in a sequence of tuffaceous muds and volcaniclastics at International Ocean Discovery Program Site U1437 and produce the longest continuous magnetic polarity stratigraphy in the history of scientific ocean drilling. Remanence measurements were filtered to remove intervals affected by fluidization, plastic sediment disturbance, and core biscuiting. Drilling overprints are concentrated in the disturbed annulus surrounding intact core material. Bioturbation was limited to a vertical extent of at most 15 cm. Changes in sediment color, stiffness, and magnetic hysteresis all suggest that remanence was locked in within a few meters of the sediment–water interface. We did not observe any systematic offset between magnetostratigraphic and biostratigraphic datums. Authigenic growth of greigite, in response to both initial sulfate reduction in the upper 50 m of the sediment column and to deeper resupply of sulfate, has led to magnetic overprinting. Anomalous polarity artefacts, extending <5 m and occurring within about 20 m below a real polarity transition, appear to be due to a chemical remanence acquired by greigite produced during early diagenesis. Diagenetic magnetic mineral alteration resulted in the progressive loss of fine‐grained magnetite, which enhanced susceptibility to drilling and postdrilling overprints and increased the resistance of these overprints to removal by conventional demagnetization. We recovered the magnetostratigraphic record from many samples with resistant overprints through low‐temperature demagnetization through the Verwey transition.

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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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Site U1437

Cited by 13 publications

References 104 publications

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

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

Recognizing magnetostratigraphy in overprinted and altered marine sediments: Challenges and solutions from IODP Site U1437

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

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