Changes in Magnetic Parameters After Sequential Iron Phase Extraction of Eastern Mediterranean Sapropel S1 Sediments

Garming, J. F. L.; Lange, Gert J. de; Dekkers, Mark J.; Passier, Hilde F.

doi:10.1023/b:sgeg.0000020837.18450.76

Cited by 5 publications

(3 citation statements)

References 38 publications

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“…M s and M rs undergo similar stratigraphic variations; both increase sharply within oxidized sapropels, where maximum values are typically observed, and then decrease to minima within dissolution fronts beneath sapropels (Figure 4). M rs / M s increases within oxidation fronts from 0.15 to 0.5 (Figure 4), which is indicative of SSD magnetite formation (potentially of biogenic origin) that formed at the tops of sapropels during bottom water reoxygenation (Garming et al., 2004; Kruiver & Passier, 2001; Larrasoaña et al., 2006; Larrasoaña, Roberts, Stoner, et al., 2003; Passier et al., 2001). Within marls, B c and M rs / M s oscillate around values of 10 mT and 0.2, respectively, which is typical of many marine sediments (Figure 4; Garming et al., 2004; Larrasoaña et al., 2007; Passier & Dekkers, 2002; Roberts et al., 2012).…”

Section: Resultsmentioning

confidence: 98%

“…M rs / M s increases within oxidation fronts from 0.15 to 0.5 (Figure 4), which is indicative of SSD magnetite formation (potentially of biogenic origin) that formed at the tops of sapropels during bottom water reoxygenation (Garming et al., 2004; Kruiver & Passier, 2001; Larrasoaña et al., 2006; Larrasoaña, Roberts, Stoner, et al., 2003; Passier et al., 2001). Within marls, B c and M rs / M s oscillate around values of 10 mT and 0.2, respectively, which is typical of many marine sediments (Figure 4; Garming et al., 2004; Larrasoaña et al., 2007; Passier & Dekkers, 2002; Roberts et al., 2012). In contrast, high B c , B cr , and M rs / M s values indicate that high‐coercivity minerals are important in sapropels and dissolution intervals.…”

Section: Resultsmentioning

confidence: 98%

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Low‐Temperature Magnetic Properties of Marine Sediments—Quantifying Magnetofossils, Superparamagnetism, and Maghemitization: Eastern Mediterranean Examples

et al. 2021

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Periodic and marked redox changes in eastern Mediterranean marine sediments drive environmental and diagenetic changes to which magnetic minerals are sensitive. Magnetic property changes, therefore, provide useful indications of paleoceanographic conditions during and after periods of organic‐rich sediment (sapropel) deposition. Magnetic properties of eastern Mediterranean sediments at room temperature have been studied for decades; however, few studies have considered low‐temperature magnetic properties. Here, we investigate the low‐temperature (10–300 K) magnetic properties of different eastern Mediterranean sediment types combined with room temperature (∼300 K) magnetic properties, transmission electron microscopy, and calibrated X‐ray fluorescence elemental data to illustrate the valuable information that can be obtained from low‐temperature magnetic analysis of sediments. Our low‐temperature magnetic results suggest that magnetite magnetofossils and superparamagnetic (SP) particles occur widely in eastern Mediterranean sediments. SP particle contents are highest in diagenetically reduced intervals associated with sapropels. In contrast, magnetite magnetofossils are most abundant in oxidation fronts at the tops of sapropels, where strong redox gradients formed, but are also widespread throughout other sedimentary intervals that have not been subjected to extensive reductive diagenesis. Moreover, the surfaces of magnetite particles are maghemitized (i.e., partially oxidized) in oxidation fronts at the tops of sapropels, and in other oxic sediment intervals. Our results demonstrate the value of LT magnetic measurements for quantifying diverse sedimentary magnetic signals of interest in environmental magnetism when studying paleoceanographic and paleoenvironmental processes.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 98%

Low‐Temperature Magnetic Properties of Marine Sediments—Quantifying Magnetofossils, Superparamagnetism, and Maghemitization: Eastern Mediterranean Examples

et al. 2021

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“…Links between nonsteady state diagenetic conditions and oxygenation of bottom waters are well exemplified by the widespread reductive dissolution of magnetite and authigenic growth of greigite in Eastern Mediterranean sediments that result from degradation of orbitally controlled organic‐rich layers (sapropels) [ van Santvoort et al , 1997; Roberts et al , 1999; Passier et al , 2001; Kruiver and Passier , 2001; Passier and Dekkers , 2002; Larrasoaña et al , 2003b, 2006]. Downward migration of oxygen into sapropels after their formation led to authigenic magnetite formation at paleo‐oxidation fronts [ Passier et al , 2001; Kruiver and Passier , 2001; Passier and Dekkers , 2002; Larrasoaña et al , 2003b, 2006; Garming et al , 2004]. Comparison of magnetic and geochemical data indicates that diagenetic conditions associated with sapropels and the resulting magnetic signature are linked to both an enhanced supply of organic carbon and a simultaneous decrease of bottom water ventilation, with the latter factor determining the eventual magnetic properties [ Larrasoaña et al , 2003b].…”

Section: Recent Developments In Environmental Magnetismmentioning

confidence: 99%

Environmental magnetism: Principles and applications

Liu

Roberts

Larrasoaña

et al. 2012

Reviews of Geophysics

565

405

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In environmental magnetism, rock and mineral magnetic techniques are used to investigate the formation, transportation, deposition, and postdepositional alterations of magnetic minerals under the influences of a wide range of environmental processes. All materials respond in some way to an applied magnetic field, and iron‐bearing minerals are sensitive to a range of environmental processes, which makes magnetic measurements extremely useful for detecting signals associated with environmental processes. Environmental magnetism has grown considerably since the mid 1970s and now contributes to research in the geosciences and in branches of physics, chemistry, and biology and environmental science, including research on climate change, pollution, iron biomineralization, and depositional and diagenetic processes in sediments to name a few applications. Magnetic parameters are used to routinely scan sediments, but interpretation is often difficult and requires understanding of the underlying physics and chemistry. Thorough examination of magnetic properties and of the environmental processes that give rise to the measured magnetic signal is needed to avoid ambiguities, complexities, and limitations to interpretations. In this review, we evaluate environmental magnetic parameters based on theory and empirical results. We describe how ambiguities can be resolved by use of combined techniques and demonstrate the power of environmental magnetism in enabling quantitative environmental interpretations. We also review recent developments that demonstrate the mutual benefit of environmental magnetism from close collaborations with biology, chemistry, and physics. Finally, we discuss directions in which environmental magnetism is likely to develop in the future.

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Magnetic susceptibility of eastern Mediterranean marine sediments as a proxy for Saharan dust supply?

2008

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Changes in Magnetic Parameters After Sequential Iron Phase Extraction of Eastern Mediterranean Sapropel S1 Sediments

Cited by 5 publications

References 38 publications

Low‐Temperature Magnetic Properties of Marine Sediments—Quantifying Magnetofossils, Superparamagnetism, and Maghemitization: Eastern Mediterranean Examples

Low‐Temperature Magnetic Properties of Marine Sediments—Quantifying Magnetofossils, Superparamagnetism, and Maghemitization: Eastern Mediterranean Examples

Environmental magnetism: Principles and applications

Magnetic susceptibility of eastern Mediterranean marine sediments as a proxy for Saharan dust supply?

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