Sediments and micronodules in the northern and central Peru Basin

Stoffers, Peter; Sioulas, A.; Glasby, G. P.; Schmitz, W.; Mangini, Augusto

doi:10.1007/bf01820888

Cited by 21 publications

(6 citation statements)

References 46 publications

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“…The almost constant Ni to Cu ratios recorded for both the nodule and micronodules in the present study suggest that, during dredging, only nodules and micronodules occurring in the surficial sediment layer were collected. Indeed, as Ni is more mobile than Cu, it generally sharply decreases with sediment depth (Stoffers et al 1984). The marked Ce negative anomaly recorded in the chondrite-normalized REE diagram for all Clarion-Clipperton samples, i.e.…”

Section: Discussionmentioning

confidence: 84%

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Major and trace element distributions in manganese nodules and micronodules as well as abyssal clay from the Clarion-Clipperton abyssal plain, Northeast Pacific

Duliu

Alexe²,

Moutte³

et al. 2008

Geo-Mar Lett

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Section: Discussionmentioning

confidence: 84%

“…This can be attributed to the selective enrichment of CaO and P 2 O 3 recorded in the micronodule samples, due to the presence of microorganism tests (Stoffers et al 1984;Dekov et al 2003).…”

Section: Discussionmentioning

confidence: 91%

Major and trace element distributions in manganese nodules and micronodules as well as abyssal clay from the Clarion-Clipperton abyssal plain, Northeast Pacific

Duliu

Alexe²,

Moutte³

et al. 2008

Geo-Mar Lett

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“…This might be due to the generally lower sedimentation rates and to the difficulty in defining a high-resolution stratigraphic framework necessary for paleoclimatic and paleoceanographic investigations. The cruise 11 with RV SONNE to the Peru Basin concentrated on manganese nodules and on general sedimentological aspects [e.g., Halbach et al, 1980;Stoffers et al, 1982Stoffers et al, , 1984. We extend these investigations and focus in detail on paleoceanographic reconstructions using carbonate sediments.…”

Section: Introductionmentioning

confidence: 92%

Carbonate preservation history in the Peru Basin: Paleoceanographic implications

Weber¹,

Wiedicke²,

Riech³

et al. 1995

Paleoceanography

212

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We studied preservation/dissolution cycles and paleoproductivity in eight sediment cores from the Peru Basin south of the highly productive surface waters of the eastern equatorial Pacific. Stratigraphy is based on stable oxygen isotopes and on combined magnetostratigraphy and biostratigraphy. Sediment cores which span the last 8 m.y., were retrieved during cruise 79 with RV SONNE close to the carbonate compensation depth (CCD). In general, sediments show Pacific‐type carbonate cycles. We interpret a pronounced carbonate peak between 6 and 7 Ma as the result of a western and northern extension of the highly productive Peru Current. Decreased carbonate contents from the late Miocene to the late Pliocene might be associated with a slow contraction of the latitudinal extent of the high‐productivity belt north of the study areas. During the Pliocene, carbonate variations showed 400 kyr cycles indicating the growth and decay of ice sheets, which should have been associated with pulsations of the Antarctic ice cap. An abrupt collapse of the carbonate system occurred at 2.4 Ma. Higher frequency variations of the carbonate record indicate the major increase of the northern hemisphere glaciation. During the Quaternary, carbonate fluxes are high during glacials and low during interglacials. Large amplitude variations with long broad minima and maxima, associated with small migrations of the lysocline and the CCD (< 200 m), are indicative of the preservation/dissolution history in the Peru Basin. During the early Pleistocene, climatic forcing by the 41 kyr obliquity cycle is not observed in the carbonate record. During the last 800 kyr, variability in the carbonate record was dominated by the 100 kyr eccentricity cycle. Fluxes of biogenic material (calcium carbonate, organic carbon, opal, and barium) were greatest during glacials, which imply higher productivity and export production of the Peru Current during cold climatic periods. Dissolution was greatest during interglacials as inferred from the relatively poor preservation of planktonic foraminifera and from the low accumulation rate of carbonate. After the Mid‐Brunhes Event (400 ka), we observe a plateaulike shift to enhanced dissolution and to intensified productivity.

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“…These ores as well as the surrounding sediments (e.g., HEATH and DYMOND, 1977;STOFFERS et al, 1984) therefore represent a strong potential for the release of heavy metals in amounts that might be toxic for the deep-sea ecosystem. The investigation of the reactions of heavy metals after physical disturbance of seabed covered by manganese nodules was subject of the GECOMET project (Geochemical-ecological evaluation of experiments for the study of the deep-sea heavy metal cycle) which was part of the German co-operative project ATESEPP (Impacts of potential technical interventions on the deep-sea ecosystem of the southeast Pacific off Peru; see map Fig.…”

Section: Ferromanganese Nodules As Potential Sources For Heavy Metal mentioning

confidence: 99%

Reactions of the Heavy Metal Cycle to Industrial Activities in the Deep Sea: An Ecological Assessment

Koschinsky

Borowski

Halbach

2003

International Review of Hydrobiology

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This article focuses on possible geochemical consequences of potential industrial activities in the deep sea, such as manganese nodule mining, for the heavy metal cycle of the deep sea and possible reactions of the benthic ecosystem. The metal fluxes induced by sediment resuspension are compared with fluvial, atmospheric, and hydrothermal metal fluxes into the ocean. The results of geochemical laboratory experiments and analyses of deep-sea benthic organisms are discussed with respect to their ecological importance in case of a seabed disturbance.A limited short-term increase of heavy metal concentrations in the benthic layer will probably cause only negligible harmful effects on the biota. An essential precondition is that the geochemical milieu remains largely unchanged; especially variations of the redox conditions would result in changes in metal speciation, bioavailability, and toxicity.1. Introduction Ferromanganese Nodules as Potential Sources for Heavy Metal Contamination in Deep-Sea EnvironmentsThe deep-sea basins, e.g., the Peru Basin in the southern Central Pacific and the ClarionClipperton-Fracture Zone in the northern Central Pacific, contain metal-rich manganese nodules of potential economic interest (HALBACH et al., 1988). Intense scientific work was carried out in the seventies and eighties to investigate the geochemistry and metal potential of these deposits (e.g., CRONAN, 1977;CALVERT, 1978;PIPER and WILLIAMSON, 1977;EXON, 1983;DYMOND et al., 1984;GLASBY et al., 1986). However, it was soon recognized that mining of these resources would cause a number of rapid changes of the environmental conditions in large deep-sea areas which naturally can happen only in geological time scales (AMOS, 1977;PADAN, 1990;THIEL et al., 1993). Consequently, the potential effects of deepsea mining became subject of scientific activities which lead, e.g., to the publication of a special issue of Marine Mining (Vol. 3, nos. 1/2, 1981) and to the organization of a Dahlem Workshop (1991) that was dedicated to various aspects of the use and misuse of the seafloor (HSÜ and THIEDE, 1992). Some recent articles give overviews on environmental impact investigations during the past 25 years, such as the American DOMES (Deep-Ocean Mining Environmental Studies) and BIE (Benthic Impact Experiment) studies and the Ger-

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Sediments and micronodules in the northern and central Peru Basin

Cited by 21 publications

References 46 publications

Major and trace element distributions in manganese nodules and micronodules as well as abyssal clay from the Clarion-Clipperton abyssal plain, Northeast Pacific

Major and trace element distributions in manganese nodules and micronodules as well as abyssal clay from the Clarion-Clipperton abyssal plain, Northeast Pacific

Carbonate preservation history in the Peru Basin: Paleoceanographic implications

Reactions of the Heavy Metal Cycle to Industrial Activities in the Deep Sea: An Ecological Assessment

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