Reliable extraction of a deepwater trace metal isotope signal from Fe–Mn oxyhydroxide coatings of marine sediments

Gutjahr, Marcus; Frank, Martin; Stirling, Claudine H.; Klemm, Veronika; Flierdt, Tina van de; Halliday, Alex N.

doi:10.1016/j.chemgeo.2007.03.021

Cited by 211 publications

(221 citation statements)

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“…3bed). The Sr isotope results displayed in Table 1 are higher than present-day seawater ( 87 Sr/ 86 Sr seawater w 0.70917) (Henderson et al, 1994) and indicate that the aluminosilicate fraction in the sediment was also partially attacked, a feature that has been observed previously (Gutjahr et al, 2007). Nevertheless the REE patterns shown in Fig.…”

Section: Extracted Leachate Major and Trace Element Compositionmentioning

confidence: 48%

“…Following centrifugation and triple rinses in deionised water (Milli-Q system), the FeeMn oxyhydroxides were dissolved by leaching the samples for one hour in a shaker in a 0.05 M hydroxylamine hydrochloride (HH) e 15% distilled acetic acid. In contrast to the method described in Gutjahr et al (2007), neither Na-EDTA nor NaOH were added to the reductive leaching solution and the samples were only leached for one hour as opposed to three hours, which led to significantly reduced Nd yields compared with this earlier study. Na-EDTA was not added to the reductive leaching solution since only Nd and Sr were extracted for purification and isotopic analyses, and partial readsorption of leached REEs is not a major issue compared with other more particle-reactive elements such as Th.…”

Section: Methodsmentioning

confidence: 53%

“…The bottom water 3 Nd is incorporated into sedimentary authigenic FeeMn oxyhydroxides after deposition, and in deep open ocean settings this Nd isotopic signature can be reliably extracted (e.g. Bayon et al, 2002;Piotrowski et al, 2005;Gutjahr et al, 2007). A major deglacial shift of 3e43 Nd units towards more radiogenic signatures of bottom waters in deep NE and NW Atlantic core sites was interpreted as increased presence of Southern Source Water during the LGM and the deglaciation (Gutjahr et al, 2008;Yu et al, 2008;Roberts et al, 2010).…”

Section: Water-mass Tagging By Nd Isotopesmentioning

confidence: 99%

“…In total 22 individual samples with a depositional age between 45 ka BP and 35 ka BP were analysed to obtain the Nd isotope composition of past deep water from authigenic FeeMn oxyhydroxides. Additionally the extracted major and trace element concentrations were measured and the leached Sr isotope compositions were determined for the evaluation of the seawater origin of the extracted signal following the extraction scheme described in Gutjahr et al (2007) with minor modifications, as briefly outlined below.…”

Section: Methodsmentioning

confidence: 99%

“…The aim of our study is to evaluate provenance and mixing proportions of water masses in the deep western North Atlantic during MIS 3 using the authigenic FeeMn oxyhydroxide-derived Nd isotope composition of past deepwater recorded in marine sediments (Palmer and Elderfield, 1985;Rutberg et al, 2000;Bayon et al, 2002;Piotrowski et al, 2005;Gutjahr et al, 2007Gutjahr et al, , 2008Klevenz et al, 2008;Roberts et al, 2010). The isotopic composition of Nd in seawater is primarily set by riverine continental runoff (Frank, 2002;Goldstein and Hemming, 2003), exchange with shelf sediments at the ocean's boundaries (Lacan and Jeandel, 2005a), dust input and possibly submarine groundwater discharge (Johannesson and Burdige, 2007 (Jeandel et al, 1995;Tachikawa et al, 2003).…”

Section: Water-mass Tagging By Nd Isotopesmentioning

confidence: 99%

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Changes in North Atlantic Deep Water strength and bottom water masses during Marine Isotope Stage 3 (45–35kaBP)

Gutjahr

Hoogakker

McCave

2010

Quaternary Science Reviews

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a b s t r a c tThe strength of the North Atlantic Meridional Overturning Circulation during climatically highly variable Marine Isotope Stage (MIS) 3 has attracted much attention in recent years. Here we present highresolution Nd isotope compositions of past seawater derived from authigenic FeeMn oxyhydroxides recovered from drift sediments on the Blake Ridge in the deep western North Atlantic (ODP Leg 172, Site 1060, 3481 m water depth). The data cover the period from 45 to 35 ka BP, tracing circulation changes during major Heinrich iceberg discharge event 4 (H4, w40e39 ka BP). The Nd isotope record suggests that there was no northern-source water (NSW) mass like modern NADW at the deeper part of Blake Ridge at any time between 45 and 35 ka. This is fundamentally different from the hydrographic situation during the Holocene where NADW extends below 4500 m at this location. The 3 Nd of past deep water recorded in the Blake Ridge sediments was least radiogenic during Dansgaard/Oeschger (D/O) Interstadial (IS) 8 (3 Nd ¼ À11.3) and most radiogenic immediately preceding IS 9 (3 Nd ¼ À9.8). More radiogenic compositions were also recorded during H4 (À10.2 3 Nd À9.9). The Nd isotope variability in MIS 3 matches that of a physical bottom current strength reconstruction from the same location. Neither record follows the pattern of Northern Hemisphere D/O climatic cycles. In our record, reduced mixing with northern source waters started in stadial 12 and lasted until after H4 in stadial 9, followed by a rapid increase in NSW contribution thereafter. This major change in the Nd isotope record predates the iceberg discharge event Heinrich 4 by more than 3 ka indicating a shallowing of the water mass boundary between Glacial North Atlantic Intermediate Water and Southern Source Water beneath. This early change in bottom water properties at the deep Blake Ridge suggests that North Atlantic deep water advection may already have decreased several thousand years before the actual iceberg discharge event and associated freshening of the surface waters in the North Atlantic. The change can thus not be attributed to climatic events in the North Atlantic but may be related to changes in flux of deep water from the South.

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Section: Extracted Leachate Major and Trace Element Compositionmentioning

confidence: 48%

Section: Methodsmentioning

confidence: 53%