Metal accumulation rates in northwest Atlantic pelagic sediments

Thomson, J.; Carpenter, M.S.N.; Colley, Sarah; Wilson, T.R.S.; Elderfield, Henry; Kennedy, H.A.

doi:10.1016/0016-7037(84)90376-4

Cited by 117 publications

(20 citation statements)

References 45 publications

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“…The organisms extracting phosphate from oxic seawater usually show a negative Ce anomaly (Wright et al, 1987) and may result from the presence of calcareous and siliceous organisms, phillipsites and smectite (Goldberg et al, 1963;Piper, 1974a, b;Desprairies and Bonnot-Courtois, 1980;Tlig and Steinberg, 1982), whereas Fe oxide-rich oxic sediments, such as red clay, have a positive Ce anomaly (Piper, 1974b;Thomson et al, 1984). Conversely, in suboxic seawater, Ce containing sediments are mobilized and Ce is released into the water column, which resulted in a less negative to positive Ce anomaly in seawater (De Baar, 1991).…”

Section: Cerium Anomaly and Paleo-redox Conditionsmentioning

confidence: 99%

Geochemistry of Neoproterozoic limestones of the Shahabad Formation, Bhima Basin, Karnataka, southern India

et al. 2011

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Major, trace and rare earth element (REE) geochemistry of carbonate rocks of the Neoproterozoic Shahabad Formation, southern India were studied in order to investigate the depositional environment and source for the REEs. The PAAS (Post Archaean Australian Shale) normalized REE + Y pattern of Shahabad limestones have consistent seawater-like pattern i.e., i) LREE depletion (average (Nd/Yb) SN = 0.64 ± 0.08), ii) negative Ce anomaly, iii) positive Gd anomaly (average Gd SN /Gd * = 1.05 ± 0.16), iv) superchondritic Y/Ho ratio (average Y/Ho = 38.13 ± 21.35). The depletion of LREE and enrichment of HREE are clearly indicated by the (La/ Yb) SN , (Dy/Yb) SN and (Nd/Yb) SN ratios, which suggest the retention of seawater characteristics in these limestones. The negative Ce anomaly reflects the incorporation of REE directly from seawater or from the pore water under oxic condition, and also reveals the mixing of two-component systems with terrigenous clay (detrital) in the marine sediments. The terrigenous input in these limestones is confirmed by positive correlation of ΣREE with Al 2 O 3 , negative correlation of ΣREE with CaO and differences in Y/Ho ratios. V, Cr, and Sc, are positively correlated with Ti, and strong positive correlation of ΣREE with Fe 2 O 3 , Ni, Cr, Sc, and Y also indicate the presence of terrigenous materials in the Shahabad limestones.

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Section: Cerium Anomaly and Paleo-redox Conditionsmentioning

confidence: 99%

Geochemistry of Neoproterozoic limestones of the Shahabad Formation, Bhima Basin, Karnataka, southern India

et al. 2011

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“…Ce anomaly is mimicking the seawater REEs pattern [17]. The organisms extracting phosphate from oxic seawater show a negative Ce anomaly [19], whereas Fe oxide-rich oxic sediments, such as red clay, have a positive Ce anomaly [20].…”

Section: Ree Patternsmentioning

confidence: 79%

Determination of rare earth, major and trace elements in authigenic fraction of Andaman Sea (Northeastern Indian Ocean) sediments by Inductively Coupled Plasma-Mass Spectrometry

Alagarsamy

You

Nath

et al. 2010

Microchemical Journal

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Downcore variation of rare-earth elements (REEs) in the authigenic Fe-Mn oxides of a sediment core (covering a record of last ~40 kyr) from the Andaman Sea, a part of Indian Ocean show distinctive positive Ce and Eu anomalies. These positive Ce anomalies (Ce*=1.1~1.8) are ascribed to be due to oxidation of deep sea sediments. The large positive Eu anomalies (i.e., Eu* >1.8 to 3.2) occur within a time span near the glacial/interglacial transition (~7,000-14,000 yr BP) which could be due to the past hydrothermal activity or to the effects arising from sea level changes. During glacial times, the Andaman Sea was almost completely isolated due to low sea level, leading to a reduction in sediment supply from the Ayeyarwady river. The variations of metal abundances (i.e., Ca, Al, Mn, and Fe) in the authigenic fraction provided independent information to evaluate the water column physicochemical changes during the glacial/interglacial transition period. The studied sediment core record changes in riverine inputs and reflect depositional changes related to sea level fluctuations and climatic events over the past 40 kyr in the Andaman Sea.

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“…The lower MnO content and other metals like Cu, Co and Ni in the samples does not support the hydrogenous origin for Ramagiri schist belt BIF as well. During the precipitation of hydrogenous materials enrichment of various metals takes place (Piper 1974;Thomson et al 1984). The relationship between RREE and the sum of Co ?…”

Section: Comparison With Other Bifmentioning

confidence: 99%

Geochemistry of Late Archaean shaly BIF formed by oxic exogenic processes: an example from Ramagiri schist belt, Dharwar Craton, India

Mishra

2015

Chin. J. Geochem.

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The central block of the auriferous Ramagiri schist belt, in the Eastern Dharwar Craton, India consists of bimodal volcanics (mafic-felsic), shaly BIF and metasedimentary rocks. Geochemical studies of the associated shaly BIF have indicated the enrichment of the major and trace elements such as SiO alkali and alkaline earth elements indicates that the clastic component of the shaly BIF had their contribution from the contemporaneous bimodal volcanics. The concave chondrite normalized REE patterns share ubiquitously anomalous positive cerium anomaly, absence of positive europium anomaly and the overall HREE enrichment. The REE patterns resemble those from the modern day sea water, except for positive Ce anomaly. The data suggests that arc related bimodal volcanism had been the plausible source of Fe, silica, REE and other trace elements. The coherent behaviour of Fe, Ti, Mn and P with the REEs indicates that they got incorporated from Fe-TiMn bearing primary minerals and secondary products like clays. The variability of REE patterns in the BIF formation samples probably results from the differences in scavenging efficiency. The BIF bears signatures of mixing of the contemporaneous clastic and chemical processes, as well as the changes accompanying diagenesis and metamorphism. The precipitation of Fe did not stop during the sedimentation in an island arc related tectonic setting. The BIF strongly lacks the signatures from hydrothermal input. The presence of positive cerium anomalies and the absence of positive europium anomalies in the shaly banded ironformations imply that iron oxidation during BIF deposition took place in shallow waters rather than at depth, at oxicanoxic boundary.

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Metal accumulation rates in northwest Atlantic pelagic sediments

Cited by 117 publications

References 45 publications

Geochemistry of Neoproterozoic limestones of the Shahabad Formation, Bhima Basin, Karnataka, southern India

Geochemistry of Neoproterozoic limestones of the Shahabad Formation, Bhima Basin, Karnataka, southern India

Determination of rare earth, major and trace elements in authigenic fraction of Andaman Sea (Northeastern Indian Ocean) sediments by Inductively Coupled Plasma-Mass Spectrometry

Geochemistry of Late Archaean shaly BIF formed by oxic exogenic processes: an example from Ramagiri schist belt, Dharwar Craton, India

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