K – Goldschmidt Abstracts 2013

doi:10.1180/minmag.2013.077.5.11

Cited by 9 publications

(4 citation statements)

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“…Maslennikov et al, 2009;Deditius et al, 2011). Synchrotron radiation μ-XRF elemental distribution maps for Sb, Fe, Zn, and As in concentrically laminated pyrite 1 (Kilias et al 2013b) has revealed that Fe, Zn, As and Sb show laminae parallel quasi-linear distributions. Zn and Fe partly positively correlate, and As and Sb are also positively correlated in a linear manner parallel to the Fe and Zn distribution with some spots of elevated concentrations.…”

Section: Discussionmentioning

confidence: 99%

Antimony Fixation in Solid Phases at the Hydrothermal Field of Kolumbo Submarine Arc-Volcano (Santorini): Deposition Model and Environmental Implications

Kilias¹,

Gousgouni²,

Godelitsas³

et al. 2017

geosociety

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Section: Discussionmentioning

confidence: 99%

Antimony Fixation in Solid Phases at the Hydrothermal Field of Kolumbo Submarine Arc-Volcano (Santorini): Deposition Model and Environmental Implications

Kilias¹,

Gousgouni²,

Godelitsas³

et al. 2017

geosociety

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“…For AMS 14 C analyses, freeze-dried sediment slices of 2-2.5 cm thickness were washed over a 63 µm mesh-size sieve and dried after washing at 30 • C. At least 1.7 mg of monospecific samples of the planktic foraminifera Neogloboquadrina pachyderma sinistral were picked from the 125-250 µm fraction. This foraminifera is a subsurface-dwelling species that lives in the North Pacific between 50 and 200 m water depth (Kuroyanagi et al, 2002;Bauch et al, 2002). Radiocarbon dating on benthic foraminifera were carried out on mixed benthic, mostly shallow infaunal species (like Uvigerina spp., Elphidium spp, Nonionella spp.…”

Section: Radiocarbon Datingmentioning

confidence: 99%

Laminated sediments in the Bering Sea reveal atmospheric teleconnections to Greenland climate on millennial to decadal timescales during the last deglaciation

et al. 2014

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Abstract. During the last glacial termination, the upper North Pacific Ocean underwent dramatic and rapid changes in oxygenation that lead to the transient intensification of oxygen minimum zones (OMZs), recorded by the widespread occurrence of laminated sediments on circum-Pacific continental margins. We present a new laminated sediment record from the mid-depth (1100 m) northern Bering Sea margin that provides insight into these deglacial OMZ maxima with exceptional, decadal-scale detail. Combined ultrahigh-resolution micro-X-ray-fluorescence (micro-XRF) data and sediment facies analysis of laminae reveal an alternation between predominantly terrigenous and diatom-dominated opal sedimentation. The diatomaceous laminae are interpreted to represent spring/summer productivity events related to the retreating sea ice margin. We identified five laminated sections in the deglacial part of our site. Lamina counts were carried out on these sections and correlated with the Bølling–Allerød and Preboreal phases in the North Greenland Ice Core (NGRIP) oxygen isotope record, indicating an annual deposition of individual lamina couplets (varves). The observed rapid decadal intensifications of anoxia, in particular within the Bølling–Allerød, are tightly coupled to short-term warm events through increases in regional export production. This dependence of laminae formation on warmer temperatures is underlined by a correlation with published Bering Sea sea surface temperature records and δ18O data of planktic foraminifera from the Gulf of Alaska. The rapidity of the observed changes strongly implies a close atmospheric teleconnection between North Pacific and North Atlantic regions. We suggest that concomitant increases in export production and subsequent remineralization of organic matter in the Bering Sea, in combination with oxygen-poor waters entering the Being Sea, drove down oxygen concentrations to values below 0.1 mL L−1 and caused laminae preservation. Calculated benthic–planktic ventilation ages show no significant variations throughout the last deglaciation, indicating that changes in formation rates or differing sources of North Pacific mid-depth waters are not prime candidates for strengthening the OMZ at our site. The age models established by our correlation procedure allow for the determination of calendar age control points for the Bølling–Allerød and the Preboreal that are independent of the initial radiocarbon-based chronology. Resulting surface reservoir ages range within 730–990 yr during the Bølling–Allerød, 800–1100 yr in the Younger Dryas, and 765–775 yr for the Preboreal.

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“…ROV-operated push cores were sampled at intervals of 1 cm for solid-phase analyses. Bulk sediment data and TOC contents have been corrected after Kuhn (2013) for the interference of the pore-water salt matrix with the sediment composition (Volz et al, 2018). The salt-free volume fraction of the pore water, i.e.…”

Section: Sediment Sampling and Solid-phase Analysesmentioning

confidence: 99%

Impact of small-scale disturbances on geochemical conditions, biogeochemical processes and element fluxes in surface sediments of the eastern Clarion-Clipperton Zone, Pacific Ocean

Volz¹,

Haffert²,

Haeckel³

et al. 2019

Preprint

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<p><strong>Abstract.</strong> The thriving interest in harvesting deep-sea mineral resources, such as polymetallic nodules, calls for environmental impact studies, and ultimately, for regulations for environmental protection. Industrial-scale deep-sea mining of polymetallic nodules most likely has severe consequences for the natural environment. However, the effects of mining activities on deep-sea ecosystems, sediment geochemistry and element fluxes are still poorly conceived. Predicting the environmental impact is challenging due to the scarcity of environmental baseline studies as well as the lack of mining trials with industrial mining equipment in the deep sea. Thus, currently we have to rely on small-scale disturbances simulating deep-sea mining activities as a first-order approximation to study the expected impacts on the abyssal environment. Here, we investigate surface sediments in disturbance tracks of seven small-scale benthic impact experiments, which have been performed in four European contract areas for the exploration of polymetallic nodules in the Clarion-Clipperton Zone (CCZ). These small-scale disturbance experiments were performed 1 day to 37 years prior to our sampling program in the German, Polish, Belgian and French contract areas using different disturbance devices. We show that the depth distribution of solid-phase Mn in the upper 20 cm of the sediments in the CCZ provides a reliable tool for the determination of the disturbance depth, which has been proposed in a previous study (Paul et al., 2018). We found that the upper 5&#8211;15 cm of the sediments were removed during various small-scale disturbance experiments in the different exploration contract areas. Transient transport-reaction modelling for the Polish and German contract areas reveals that the removal of the surface sediments is associated with the loss of reactive labile organic carbon. As a result, oxygen consumption rates decrease significantly after the removal of the surface sediments, and consequently, oxygen penetrates up to tenfold deeper into the sediments inhibiting denitrification and Mn(IV) reduction. Our model results show that the post-disturbance geochemical re-equilibration is controlled by diffusion until the reactive labile TOC fraction in the surface sediments is partly re-established and the biogeochemical processes commence. While the re-establishment of bioturbation is essential, the geochemical re-equilibration of the sediments is ultimately controlled by the burial rates of organic matter. Hence, under current depositional conditions, the new geochemical equilibrium in the sediments of the CCZ is reached only on a millennia scale even for these small-scale disturbances simulating deep-sea mining activities.</p>

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K – Goldschmidt Abstracts 2013

Cited by 9 publications

References 0 publications

Antimony Fixation in Solid Phases at the Hydrothermal Field of Kolumbo Submarine Arc-Volcano (Santorini): Deposition Model and Environmental Implications

Antimony Fixation in Solid Phases at the Hydrothermal Field of Kolumbo Submarine Arc-Volcano (Santorini): Deposition Model and Environmental Implications

Laminated sediments in the Bering Sea reveal atmospheric teleconnections to Greenland climate on millennial to decadal timescales during the last deglaciation

Impact of small-scale disturbances on geochemical conditions, biogeochemical processes and element fluxes in surface sediments of the eastern Clarion-Clipperton Zone, Pacific Ocean

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