Manganese-rich brown layers in Arctic Ocean sediments: Composition, formation mechanisms, and diagenetic overprint

März, Christian; Stratmann, A.; Matthießen, Jens; Meinhardt, Ann-Katrin; Eckert, Sebastian; Schnetger, Bernhard; Vogt, Christoph; Stein, Rüdiger; Brumsack, Hans‐Jürgen

doi:10.1016/j.gca.2011.09.046

Cited by 103 publications

(62 citation statements)

References 103 publications

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“…1). Nine multicorer tubes (MUC), eight gravity cores (GC), and four box-shaped gravity cores ("Kastenlot", KL) were sampled for pore waters using rhizone samplers (~0.1 μm average pore size), with a vacuum being applied using 12 mL plastic syringes with wooden stoppers (Seeberg-Elverfeldt et al, 2005;März et al, 2011). Sampling resolution ranged from 1 cm (in MUCs, directly above and below the sediment-water interface) to 25 cm (in GCs and KLs).…”

Section: Methodsmentioning

confidence: 99%

Silica diagenesis and benthic fluxes in the Arctic Ocean

et al. 2015

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Section: Methodsmentioning

confidence: 99%

Silica diagenesis and benthic fluxes in the Arctic Ocean

et al. 2015

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“…However, Mn may be more complicated. März et al (2011) find evidence from Mn profiles along the southern Mendeleev Ridge that suggest diagenetic remobilization of Mn at depth and diffusion toward shallow sediments. The relatively deep depths of metal oxide reduction, nevertheless, are consistent with a relatively low input of POM to the seafloor and completely contrast with most sites where high CH 4 concentrations exist in shallow sediment.…”

Section: Other Chemistrymentioning

confidence: 85%

“…Here, Mn and Fe concentrations reach maxima at 1.3 and 0.5 mbsf, respectively, and decrease below. This is likely due to Mn and Fe produced during dissimilatory oxide reduction, but where both metals precipitate below into carbonate (Mn and Fe) or sulfide phases (Fe; Jørgensen et al, 1990;März et al, 2011). This is common at locations with modest POC input, and the Lomonosov Ridge site appears to receive higher organic carbon burial over time than all the other locations examined.…”

Section: Other Chemistrymentioning

confidence: 93%

Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations

et al. 2017

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Abstract. Continental slopes north of the East Siberian Sea potentially hold large amounts of methane (CH 4 ) in sediments as gas hydrate and free gas. Although release of this CH 4 to the ocean and atmosphere has become a topic of discussion, the region remains sparingly explored. Here we present pore water chemistry results from 32 sediment cores taken during Leg 2 of the 2014 joint Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions (SWERUS-C3) expedition. The cores come from depth transects across the slope and rise extending between the Mendeleev and the Lomonosov ridges, north of Wrangel Island and the New Siberian Islands, respectively. Upward CH 4 flux towards the seafloor, as inferred from profiles of dissolved sulfate (SO 2− 4 ), alkalinity, and the δ 13 C of dissolved inorganic carbon (DIC), is negligible at all stations east of 143 • E longitude. In the upper 8 m of these cores, downward SO 2− 4 flux never exceeds 6.2 mol m −2 kyr −1 , the upward alkalinity flux never exceeds 6.8 mol m −2 kyr −1 , and δ 13 C composition of DIC (δ 13 C-DIC) only moderately decreases with depth (−3.6 ‰ m −1 on average). Moreover, upon addition of Zn acetate to pore water samples, ZnS did not precipitate, indicating a lack of dissolved H 2 S. Phosphate, ammonium, and metal profiles reveal that metal oxide reduction by organic carbon dominates the geochemical environment and supports very low organic carbon turnover rates. A single core on the Lomonosov Ridge differs, as diffusive fluxes for SO 2− 4 and alkalinity were 13.9 and 11.3 mol m −2 kyr −1 , respectively, the δ 13 C-DIC gradient was 5.6 ‰ m −1 , and Mn 2+ reduction terminated within 1.3 m of the seafloor. These are among the first pore water results generated from this vast climatically sensitive region, and they imply that abundant CH 4 , including gas hydrates, do not characterize the East Siberian Sea slope or rise along the investigated depth transects. This contradicts previous modeling and discussions, which due to the lack of data are almost entirely based on assumption.

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“…The cores recovered a typical section of the deep water basin of the Arctic Ocean, which is represented by the alterna tion of sediments formed during glacial and intergla cial periods [24,33]. This is expressed in the distinctive enrichment of the sediments, which were accumu lated during relatively warm interglacial periods and became rich in biogenic carbonates (foraminifers) and, respectively, in Ca, Mg, Sr, Mn, and many trace elements in ice rafted material and their depletion in organic carbon.…”

Section: Lithostratigraphy and Composition Of The Sedimentsmentioning

confidence: 99%

“…This is expressed in the distinctive enrichment of the sediments, which were accumu lated during relatively warm interglacial periods and became rich in biogenic carbonates (foraminifers) and, respectively, in Ca, Mg, Sr, Mn, and many trace elements in ice rafted material and their depletion in organic carbon. These deposits are usually brown and strongly bioturbated, unlike the intervening gray or yellow gray sediments [24,34]. In addition, the sedi ments accumulated during relatively warm periods contain horizons enriched in detrital carbonates, which, according to many researchers [24,28,33], is related to the iceberg transfer of detrital material from the Canadian archipelago.…”

Section: Lithostratigraphy and Composition Of The Sedimentsmentioning

confidence: 99%

Possible conditions and the formation time of the Chukchi Plateau pockmarks

et al. 2014

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The study of the bottom sediments accumulated during the last 60-65 ka in the pockmark craters of the Chukchi Plateau in the Arctic Ocean showed that their composition and lithostratigraphy in general are similar to those of the background areas. A specific feature is the presence of sedimentary interlayers and horizons with signs of gravitational stirring, carbonate mineralization, and accumulation under H 2 S contam ination conditions. The micropaleontological remains found in the pockmark sediments accumulated during the glacial periods are represented by redeposited species from Paleozoic, Mesozoic, and Cenozoic deposits, which are locally exposed in the pockmark walls. It was concluded that the pockmarks were formed under the influence of pulsed fluid flows. The present day topography of the pockmarks was formed at the last stage of active defluidization (35-20 ka ago).

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Manganese-rich brown layers in Arctic Ocean sediments: Composition, formation mechanisms, and diagenetic overprint

Cited by 103 publications

References 103 publications

Silica diagenesis and benthic fluxes in the Arctic Ocean

Silica diagenesis and benthic fluxes in the Arctic Ocean

Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations

Possible conditions and the formation time of the Chukchi Plateau pockmarks

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