An ITRAX Geochemical Study of Ferromanganiferous Sediments from the Penrhyn Basin, South Pacific Ocean

Cronan, D. S.; Rothwell, Guy; Croudace, Ian W.

doi:10.1080/1064119x.2010.483001

Cited by 14 publications

(8 citation statements)

References 7 publications

(7 reference statements)

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“…Mn is a good indicator for disturbance in sediments with a relatively shallow oxic layer, such as the Peru Basin. Areas with a different redox-zonation might have different key parameters because a largely oxic system (such as the CCZ where deep-sea polymetallic nodule mining is most likely to start) will be differently impacted (also see Cronan et al, 2010;Rühlemann et al, 2011;Mewes et al, 2014Mewes et al, , 2016Mogollón et al, 2016;Kuhn et al, 2017;Volz et al, in review). We are only able to draw this conclusion about Mn as a key parameter, however, because this small site has been extensively studied over a long period of time.…”

Section: Resultsmentioning

confidence: 99%

“…Mining operations to recover nodules will likely remove or disturb the upper 10-50 cm of sediment and create a sediment plume (Thiel and Schriever, 1990;Oebius et al, 2001;Cronan et al, 2010;Gollner et al, 2017). Ex-situ experiments with sediment cores from the Peru Basin showed that pore water metals, dissolved organic carbon (DOC) and nutrients are released when the sediment is stirred up (Koschinsky et al, 2001b).…”

Section: Introductionmentioning

confidence: 99%

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Biogeochemical Regeneration of a Nodule Mining Disturbance Site: Trace Metals, DOC and Amino Acids in Deep-Sea Sediments and Pore Waters

et al. 2018

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Increasing interest in deep-sea mineral resources, such as polymetallic nodules, calls for environmental research about possible impacts of mineral exploitation on the deep-sea ecosystem. So far, little geochemical comparisons of deep-sea sediments before and after mining induced disturbances have been made, and thus long-term environmental effects of deep-sea mining are unknown. Here we present geochemical data from sediment cores from an experimental disturbance area at 4,100 m water depth in the Peru Basin. The site was revisited in 2015, 26 years after a disturbance experiment mimicking nodule mining was carried out and compared to sites outside the experimental zone which served as a pre-disturbance reference. We investigated if signs of the disturbance are still visible in the solid phase and the pore water after 26 years or if pre-disturbance conditions have been re-established. Additionally, a new disturbance was created during the cruise and sampled 5 weeks later to compare short-and longer-term impacts. The particulate fraction and pore water were analyzed for major and trace elements to study element distribution and processes in the surface sediment. Pore water and bottom water samples were also analyzed for oxygen, nitrate, dissolved organic carbon, and dissolved amino acids, to examine organic matter degradation processes. The study area of about 11 km 2 was found to be naturally more heterogeneous than expected, requiring an analysis of spatial variability before the disturbed and undisturbed sites can be compared. The disturbed sites exhibit various disturbance features: some surface sediments were mixed through, others had the top layer removed and some had additional material deposited on top. Pore water constituents have largely regained pre-disturbance gradients after 26 years. The solid phase, however, shows clear differences between disturbed and undisturbed sites in the top 20 cm so that the impact is still visible in the plowed tracks after 26 years. Especially the upper layer, usually rich in manganese-oxide Paul et al.Biogeochemical Regeneration After Mining Disturbance and associated metals, such as Mo, Ni, Co, and Cu, shows substantial differences in metal distribution. Hence, it can be expected that disturbances from polymetallic nodule mining will have manifold and long-lasting impacts on the geochemistry of the underlying sediment.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Biogeochemical Regeneration of a Nodule Mining Disturbance Site: Trace Metals, DOC and Amino Acids in Deep-Sea Sediments and Pore Waters

et al. 2018

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“…However, a novel application has been in deep marine environmental impact studies. Cronan et al (2010) used a XRF core scanner to assess chemical variability and hence substrate redox conditions along a core transect in the Penrhyn Basin (Central Pacific Ocean). This aimed to determine potential environmental impacts of Mn nodule mining should this take place.…”

Section: Environmental Impact Studiesmentioning

confidence: 99%

Twenty Years of XRF Core Scanning Marine Sediments: What Do Geochemical Proxies Tell Us?

Rothwell

Croudace

2015

Developments in Paleoenvironmental Research

130

128

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XRF core scanners, with their rapid and non-destructive analytical capability, have now been used for two decades in the analysis of marine sediments. Initially they were used to record variations in fundamental parameters such as calcium carbonate stratigraphy and terrigenous sediment delivery, using major element integrals, such as Ca and Fe, to provide detailed insights into oceanographic and climatic processes. In recent years, proxy selection has progressed to routine normalisation and presentation as log-ratios to include 60 elements or ratios to document a wide range of environmental and process changes. We review the development and application of XRF core scanning of marine sediments and discuss the basis of particular proxies, their uses and limitations to assist users in their selection. To date, there has been no systematic overview of elemental proxies and their application in the analysis of marine sediment records.

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“…Combining a continuous high-resolution record with a conversion to concentration using sub-samples analysed by ICP-OES provides a strong advantage over other methods by producing detailed geochemical profiles for the turbidites in Agadir Basin which allow assessment of bed provenance. Core scanner XRF data have been previously used for turbidite correlations, sediment provenance and sediment diagenesis studies ; Thomson et al 2006;Giresse et al 2009;Cronan et al 2010). ITRAX μXRF data has been previously used to aid identification of volcaniclastic and siliciclastic turbidites from Agadir Basin (Frenz et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Use of Calibrated ITRAX XRF Data in Determining Turbidite Geochemistry and Provenance in Agadir Basin, Northwest African Passive Margin

Hunt

Croudace

Maclachlan

2015

Micro-XRF Studies of Sediment Cores

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The Agadir Basin is a mixed siliciclastic-volcaniclastic deepwater turbidite system derived from several sedimentary sources. Estimating the influence of these sources requires detailed geochemical profiles of sediment cores. This is achieved using an ITRAX µXRF core scanner that normally produces elemental profiles in units of counts or count rate. Improved insights are achieved if the ITRAX data are calibrated to produce concentration data. Turbidite geochemistry can then be used to more reliably infer the sources of flows and identify primary sediment sources, which are the Moroccan slope for siliciclastic beds and the western Canary Islands for volcaniclastic turbidites. Cross-plots of the geochemical data discriminate variations between different siliciclastic and volcaniclastic beds. For example, differences between two distinctive volcaniclastic marker beds, named A2 and A14, reflect differences in their respective Canary Island sources and indicate a primitive basaltic source for bed A2 and an evolved source for bed A14. Compositional variations between siliciclastic deposits reflect potential variations in the sediment source that failed or the location of the failure on the Moroccan continental slope.

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An ITRAX Geochemical Study of Ferromanganiferous Sediments from the Penrhyn Basin, South Pacific Ocean

Cited by 14 publications

References 7 publications

Biogeochemical Regeneration of a Nodule Mining Disturbance Site: Trace Metals, DOC and Amino Acids in Deep-Sea Sediments and Pore Waters

Biogeochemical Regeneration of a Nodule Mining Disturbance Site: Trace Metals, DOC and Amino Acids in Deep-Sea Sediments and Pore Waters

Twenty Years of XRF Core Scanning Marine Sediments: What Do Geochemical Proxies Tell Us?

Use of Calibrated ITRAX XRF Data in Determining Turbidite Geochemistry and Provenance in Agadir Basin, Northwest African Passive Margin

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