Rock magnetic properties, magnetic susceptibility, and organic geochemistry comparison in core LZ1029-7 Lake El'gygytgyn, Far Eastern Russia

Abstract. Susceptibility measurements performed on initial short (3–16 m) cores taken from Lake El'gygytgyn exhibited a large range in values. This observation led to the suggestion of widespread magnetite dissolution within the sediments due to anoxic conditions within the lake. Rock magnetic properties and their comparison with magnetic susceptibility, Total Organic Carbon (TOC), and bulk δ13Corg proxies in core LZ1029-7 provide an insight into the character of the magnetic minerals present within the lake and can further the understanding of processes that may be present in the newer long core sediments Susceptibility measurements (χ) of discrete samples corroborate the two order of magnitude difference seen in previous continuous susceptibility measurements (κ), correlating high values with interglacial periods and low values with glacial intervals. Hysteresis parameters defined the majority of the magnetic material to be magnetite of PSD size. TOC values increase while δ13Corg values decrease in one section of LZ1029-7, which is defined as the Last Glacial Maximum (LGM), and help confine the age of the core to approximately 62 kyr. Increases in TOC during the most recent glacial interval suggest increased preservation of organic carbon during these times High TOC and low magnetic susceptibility during the LGM support the theory of perennial ice cover during glacial periods, which would lead to lake stratification and therefore anoxic bottom water conditions. Low temperature magnetic measurements also confirmed the presence of magnetite, but also indicated titanomagnetite, siderite and/or rhodochrosite, and vivianite were present. The latter three minerals are found only in anoxic environments, and further support the notion of magnetite dissolution.

Download Full-text

Rock magnetic properties, magnetic susceptibility, and organic geochemistry comparison in core LZ1029-7 Lake El'gygytgyn, Russia Far East

Climate of the Past ◽

10.5194/cp-9-467-2013 ◽

2013 ◽

Vol 9 (1) ◽

pp. 467-479 ◽

Cited By ~ 20

Author(s):

K. J. Murdock ◽

K. Wilkie ◽

L. L. Brown

Keyword(s):

Magnetic Properties ◽

Magnetic Susceptibility ◽

Organic Carbon ◽

Magnetic Measurements ◽

Organic Geochemistry ◽

Far East ◽

Magnetic Minerals ◽

Rock Magnetic Properties ◽

Lake El’Gygytgyn ◽

Order Of Magnitude

Abstract. Susceptibility measurements performed on initial short (~ 16 m) cores PG1351 taken from Lake El'gygytgyn exhibited a large range in values. This observation led to the suggestion of widespread magnetite dissolution within the sediments due to anoxic conditions within the lake. Rock magnetic properties and their comparison with magnetic susceptibility, total organic carbon (TOC), and bulk δ13Corg proxies in core LZ1029-7, taken from the same site as the previously drilled PG1351, provide an insight into the character of the magnetic minerals present within the lake and can further the understanding of processes that may be present in the newer long core sediments. Susceptibility measurements (χ) of discrete samples corroborate the two order of magnitude difference seen in previous continuous susceptibility measurements (κ), correlating high values with interglacial periods and low values with glacial intervals. Hysteresis parameters indicate that the majority of the magnetic material to be magnetite of PSD size. TOC values increase while δ13Corg values decrease in one section of LZ1029-7, which is defined as the Last Glacial Maximum (LGM), and help confine the age of the core to approximately 62 ka. Increases in TOC during the most recent glacial interval suggest increased preservation of organic carbon during this period. High TOC and low magnetic susceptibility during the LGM support the theory of perennial ice cover during glacial periods, which would lead to lake stratification and therefore anoxic bottom water conditions. Low temperature magnetic measurements confirmed the presence of magnetite, but also indicated titanomagnetite and possibly siderite, rhodochrosite, and/or vivianite were present. The latter three minerals are found only in anoxic environments, and further support the notion of magnetite dissolution.

Download Full-text

High-temperature thermomagnetic properties of vivianite nodules, Lake El'gygytgyn, Northeast Russia

Climate of the Past ◽

10.5194/cp-9-433-2013 ◽

2013 ◽

Vol 9 (1) ◽

pp. 433-446 ◽

Cited By ~ 14

Author(s):

P. S. Minyuk ◽

T. V. Subbotnikova ◽

L. L. Brown ◽

K. J. Murdock

Keyword(s):

Magnetic Susceptibility ◽

High Temperature ◽

Magnetic Measurements ◽

Iron Phosphate ◽

Northeastern Russia ◽

Northeast Russia ◽

Low Field ◽

Lake El’Gygytgyn ◽

Monoclinic Pyrrhotite ◽

Thermomagnetic Properties

Abstract. Vivianite, a hydrated iron phosphate, is abundant in sediments of Lake El'gygytgyn, located in the Anadyr Mountains of central Chukotka, northeastern Russia (67°30′ N, 172°05′ E). Magnetic measurements, including mass-specific low-field AC magnetic susceptibility, field-dependent magnetic susceptibility, hysteresis parameters, temperature dependence of the induced magnetization, as well as susceptibility in different heating media, provide ample information on vivianite nodules. Electron microprobe analyses, electron microscopy and energy dispersive spectroscopy were used to identify diagnostic minerals. Vivianite nodules are abundant in both sediments of cold (anoxic) and warm (oxic) stages. Magnetic susceptibility of the nodules varies from 0.78 × 10−6 m3 kg−1 to 1.72 × 10−6 m3 kg−1 (average = 1.05 × 10−6 m3 kg−1) and is higher than the susceptibility of sediments from the cold intervals. Magnetic properties of vivianite are due to the respective product of oxidation as well as sediment and mineral inclusions. Three types of curves for high-temperature dependent susceptibility of vivianite indicate different degrees of oxidation and inclusions in the nodules. Vivianite acts as a reductant and reduces hematite to magnetite and masks the goethite–hematite transition during heating. Heating vivianite and sulfur mixtures stimulates the formation of monoclinic pyrrhotite. An additive of arsenic inhibits the formation of magnetite prior to its Curie temperature. Heating selective vivianite and pyrite mixtures leads to formation of several different minerals – magnetite, monoclinic pyrrhotite, and hexagonal pyrrhotite, and makes it difficult to interpret the thermomagnetic curves.

Download Full-text

Magnetic Signatures on River Sediments and Agricultural Soils as Proxy Indicators of Anthropogenic-derived Pollution (Case Study: Cikijing River, Rancaekek, West Java)

Jurnal Penelitian Pendidikan IPA ◽

10.29303/jppipa.v7i3.697 ◽

2021 ◽

Vol 7 (3) ◽

pp. 381

Author(s):

Dini Fitriani ◽

Widya Utami ◽

Kartika Hajar Kirana ◽

Eleonora Agustine ◽

Siti Zulaikah

Keyword(s):

Magnetic Properties ◽

Magnetic Susceptibility ◽

Agricultural Soils ◽

River Sediments ◽

Paddy Fields ◽

Composition Analysis ◽

Magnetic Minerals ◽

West Java ◽

Anthropogenic Pollutants ◽

Magnetic Signatures

A number of activities occur around the Cikijing River in Rancaekek area, West Java, such as industrial and domestic activities. The various activities could decrease the quality of the river and surrounding environment due to anthropogenic pollutants that might be produced. Since the Cikijing River is also used as the source of irrigation, paddy fields around the river could be also be affected. The presence of pollutants in river sediments and agricultural soils over a long period could change their magnetic properties. Magnetic susceptibility of Cikijing River sediments and soils of the paddy fields in the surrounding have been examined considering that magnetic properties could represent environmental conditions. The results show that river sediments have magnetic susceptibility (cLF) in range of 356.2-456.3 (×10-8) m3kg-1, whereas soils samples have cLF varying from 94.1 to 347.1 (×10-8) m3kg-1, suggesting domination of ferrimagnetic minerals. The cFD (%) is <4% indicating the anthropogenic origin of magnetic minerals. Electron microscopy images show the imperfect octahedral and spherules shapes of magnetic grains that supports magnetic susceptibility analysis about the source of magnetic minerals. Elemental composition analysis reveals Fe and O’s content as main elements, including minor elements of Ca, Mg, Al. Si, Ti and Cr

Download Full-text

DC and AC Measurements of Magnetite Nanoparticulates and Implications for Nonlinear Response

MRS Proceedings ◽

10.1557/proc-1138-ff03-30 ◽

2008 ◽

Vol 1138 ◽

Author(s):

Silvia Liong ◽

Ricky Lamar Moore

Keyword(s):

Particle Size ◽

Magnetic Properties ◽

Polymer Composites ◽

Magnetic Measurements ◽

Bulk Material ◽

Low Frequency ◽

Anisotropy Field ◽

Coaxial Line ◽

Magnetic Data ◽

Order Of Magnitude

AbstractThis paper discusses preparation, characterization and measurement of linear DC and AC magnetic properties of magnetite (Fe3O4) nanoparticles (size ranges of 7-50 nm and 5 microns) and polymer composites of those particulates. Selected data and analysis are taken from the PhD thesis of Liong [1]. The goal of this research is to obtain magnetic data, specifically magnetization, anisotropy and coercivity as functions of particle size. These will be used as inputs to non linear magnetic simulations and in planning for future nonlinear magnetic measurements. Magnetite nanoparticles were synthesized by chemical coprecipitation, a method that allowed for the production of samples in gram quantities. Vibrating sample magnetometry was used to measure the room-temperature DC magnetization and coercivity of the particulates. Coaxial line impedance measurements were used to measure low frequency and dispersive AC permeability of Fe3O4–polymer composites from 1 Megahertz to 10 Gigahertz. AC data are applied to infer particulate magnetic susceptibility and anisotropy field change with particle size. Particle size was calculated from XTD data and supported by TEM images.Measured DC saturation magnetization and coercivity decreased with particle dimension while anisotropy was calculated to increase. Magnetization data are consistent with models that calculate nanoparticle magnetization as a volumetric average of a spherical bulk material core and a passive outer shell. The shell thickness was calculated at 0.84 nm, very near one lattice constant of bulk Fe3O4, 0.8394 nm. Composites containing particulate volume fractions less than 20% were fabricated. Effective media theory was applied to measured AC composite permeability to extract particle magnetic properties and thereby anisotropy field, which increased by an order of magnitude from the bulk. Permeability decreased with particulate size.

Download Full-text

High Temperature and High Pressure Synthesis and Magnetic Properties of Arsenic-Based Filled Skutterudite Compounds

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.289.85 ◽

2019 ◽

Vol 289 ◽

pp. 85-92

Author(s):

Chihiro Sekine ◽

Toshihide Osanai ◽

Hariharan Ponmani ◽

Atachariya Phuangyod ◽

Yukihiro Kawamura ◽

...

Keyword(s):

High Pressure ◽

Magnetic Properties ◽

Electrical Resistivity ◽

Magnetic Susceptibility ◽

Magnetic Measurements ◽

Spin Fluctuations ◽

Filled Skutterudite ◽

Lattice Constants ◽

Pressure Synthesis ◽

New Superconductor

We have succeeded in synthesizing new arsenic-based filled skutterudite compounds CaFe4As12and BaOs4As12under high pressure. These compounds have lattice constants of 8.3288 and 8.5809 Å, respectively. The magnetic properties of CaFe4As12and BaOs4As12have been studied by means of electrical resistivity, magnetic susceptibility and magnetization measurements. The electrical resistivity and magnetic measurements indicate that CaFe4As12is a nearly ferromagnetic metal with spin fluctuations of Fe 3delectrons and BaOs4As12is a new superconductor with a transition temperature around 3 K.

Download Full-text

Magnetic Susceptibility of Soils from Eastern Botswana: A Reconnaissance Survey and Potential Applications

Journal of Geography and Geology ◽

10.5539/jgg.v7n4p45 ◽

2015 ◽

Vol 7 (4) ◽

pp. 45 ◽

Cited By ~ 2

Author(s):

Rubeni Tawanda Ranganai ◽

Moikwathai Moidaki ◽

James G. King

Keyword(s):

Magnetic Properties ◽

Magnetic Susceptibility ◽

Land Use Planning ◽

Magnetic Measurements ◽

Parent Material ◽

Appreciable Amount ◽

Frequency Dependent ◽

Magnetic Susceptibilities ◽

Basement Rocks ◽

Rock And Soil

Soil magnetic properties measurements are relatively fast and inexpensive but have been proved to be sufficient for preliminary investigations in diverse socio-developmental issues. This paper presents results of a reconnaissance study of soil colour and magnetic susceptibility (c) in eastern Botswana, where ~80% of the population resides. The work is a first step to creating a database of rock and soil magnetic properties and to document spatial variations in magnetic properties in the country. These measurements are important as constraints for interpretation of available aeromagnetic data and can also be exploited for environmental soil research (pollution) and land-use planning (agriculture). The soils sampled include derivatives of varying types and provenance such as Archean gneissic granitoids, metamorphosed rocks (granulites), volcano-sedimentary assemblages, Karoo basalts, and alluvial sediments. A soil colour chart was used since soil colours and magnetic properties are diagnostic of its parent rock sources and weathering profiles. Soil magnetic susceptibilities were measured at both low frequency (0.46 MHz, clf) and high frequency (4.6 MHz, chf), thus allowing calculation of frequency-dependent susceptibility (cfd, cfd%) for detecting ultra-fine ferromagnetic minerals.It was found that soils with Hues ranging from 7.5YR to 10YR have appreciable amount of magnetic materials and soils with Hues of 2.5YR are generally nonmagnetic. The results of soil magnetic susceptibility profiles show spatial variation closely related to the variation in basement rocks, which provides excellent evidence that the magnetic susceptibility variation reflects basement rocks or bedrock composition (soil parent material). In relation to the Botswana physiographic units, soils from the hardveld (Precambrian) show the highest susceptibilities, followed by those from the sandveld, with the lowest values being from the alluvial. The frequency dependent magnetic susceptibilities indicate the presence of ultra-fine super-paramagnetic minerals such as magnetite/maghemite. It is suggested that a systematic and continuous programme of rock and soil magnetic measurements would benefit various socio-economic and development priority sectors of Botswana. This also applies to many developing countries in Africa where soil physics and measurement of soil susceptibility in particular, is generally still at an embryonic stage.

Download Full-text

Bulk Modulus of the YBaCuO Oxide Superconductor Obtained from Magnetic Measurements

MRS Proceedings ◽

10.1557/proc-169-1105 ◽

1989 ◽

Vol 169 ◽

Author(s):

Bokhimi

Keyword(s):

Magnetic Susceptibility ◽

Bulk Modulus ◽

Room Temperature ◽

Magnetic Measurements ◽

Oxygen Deficiency ◽

External Pressure ◽

Charge Carriers ◽

Oxide Superconductor ◽

Mechanical Measurements ◽

Order Of Magnitude

AbstractStarting from the fact that the YBa2Cu3O7-x oxide superconductor system has a constant magnetic susceptibility at high temperatures for each oxygen deficiency x, and assuming that the charge carriers have a free-electron-like behavior, the observed magnetic susceptibility of the samples at room temperature can be associated to the Pauli paramagnetismus and to the Landau diamagnetism of the charge carriers. This result allows one to calculate the charge carriers density from the magnetic susceptibility in the sample. If besides one assume that by applying an external pressure on the sample, there is a change of the volume of the unit cell, but not in the number of the charge carriers in it, then, it is possible to calculate the Bulk modulus of the YBaCuO system at room temperature starting from these magnetic measurements. The obtained results are of the same order of magnitude to those reported in the literature and obtained from thermodynamic and mechanical measurements.

Download Full-text

Magnetic Properties of a Holocene Sediment Core from the Yeongsan Estuary, Southwest Korea: Implications for Diagenetic Effects and Availability as Paleoenvironmental Proxies

Frontiers in Earth Science ◽

10.3389/feart.2021.593332 ◽

2021 ◽

Vol 9 ◽

Author(s):

Hyeon–Seon Ahn ◽

Jaesoo Lim ◽

Sung Won Kim

Keyword(s):

Grain Size ◽

Magnetic Properties ◽

Magnetic Susceptibility ◽

South Korea ◽

Size Distribution ◽

Sea Level ◽

West Coast ◽

Magnetic Minerals ◽

The West ◽

Saturation Moment

The sensitivity of magnetic properties, which characterize the mineralogy, concentration, and grain size distribution of magnetic minerals, to environmental processes may provide useful information on paleoenvironmental changes in estuarine environments. Magnetic property studies of estuaries are less common than other environments and, due to the west coast of South Korea having an abundance of estuaries, it provides a good place to study these processes. In this study, we analyzed a variety of magnetic properties based on magnetic susceptibility, hysteresis parameters, progressive acquisition of isothermal remanent magnetization and first-order reversal curve data from a Holocene muddy sediment core recovered from the Yeongsan Estuary on the west coast of South Korea. We examined diagenetic effects on magnetic properties and tested their availability as proxies of paleoenvironmental change. The presence of generally low magnetic susceptibility, ubiquitous greigite-like authigenic magnetic component, and very fine magnetic particle occurrence suggested that the analyzed sediments had undergone considerable early diagenetic alteration. Electron microscopic observations of magnetic minerals support this suggestion. Our results confirm that the use of initial bulk susceptibility as a stand-alone environmental change proxy is not recommended unless it is supported by additional magnetic analyses. We recognized the existence of ferromagnetic-based variabilities related to something besides the adverse diagenetic effects, and have examined possible relationships with sea-level and major climate changes during the Holocene. The most remarkable finding of this study is the two distinct intervals with high values in magnetic coercivity (Bc), coercivity of remanence (Bcr), and ratio of remanent saturation moment to saturation moment (Mrs/Ms) that were well coincident with the respective abrupt decelerations in the rate of sea-level rise occurred at around 8.2 and 7 thousand years ago. It is then inferred that such condition with abrupt drop in sea-level rise rate would be favorable for the abrupt modification of grain size distribution toward more single-domain-like content. We modestly propose consideration of the Bc, Bcr, and Mrs/Ms variability as a potential indicator for the initiation/occurrence of sea-level stillstand/slowstand or highstand during the Holocence, at least at estuarine environments in and around the studied area.

Download Full-text

Magnetic monitoring of PM filters from Air Monitoring Stations during the COVID-19 lockdown in Rome, Italy (March 10th - May 18th, 2020)

10.5194/egusphere-egu21-3817 ◽

2021 ◽

Author(s):

Aldo Winkler ◽

Antonio Amoroso ◽

Alessandro Di Giosa ◽

Giada Marchegiani

Keyword(s):

Magnetic Susceptibility ◽

Air Quality ◽

Urban Areas ◽

Magnetic Measurements ◽

Air Monitoring ◽

Magnetic Minerals ◽

Concentration Data ◽

Local Conditions ◽

The Impact ◽

Monitoring Stations

An extensive survey of the magnetic properties of PM filters from selected air monitoring stations in Rome and other localities in Latium Region (Sacco Valley, Civitavecchia, Fiumicino) was conducted for outlining the impact of the lockdown measures on air quality.The magnetic measurements highlighted a relevant content of magnetic minerals, mostly attributable to traffic related sources, on the filters from two stations in Rome and two stations from the urban areas of Civitavecchia and Fiumicino.The PM filters from the Sacco Valley showed reduced concentrations of magnetic minerals, compared to Rome, however higher than the Castel Di Guido and Civitavecchia Sant'Agostino control stations.The daily PM concentration data did not generally correlate with the mass susceptibility data, indicating that PM was often dominated by non-ferromagnetic contents, presumably due to wind-driven natural dusts, as stressed by the frequent anticorrelation between mass magnetic susceptibility and PM concentration.In Magnagrecia air quality station, Rome, the average values &#8203;&#8203;of the concentration depending magnetic parameters resulted about a half of those measured in 2005 on the filters from the same station.From the Day plot, the filters with higher magnetic susceptibility values showed relatively coarse magnetite-like particles as the main magnetic minerals, ascribable to non-exhaust PM emissions from brakes.This study confirmed that the interpretation of PM concentration during the lockdown is not straightforward and depends on many factors, such as natural inputs, resuspension and local conditions; anyway, magnetic analyses confirmed to be a valuable tool in PM source apportionment and concentration data interpretation.

Download Full-text

The magnetic properties of natural pigments: preliminary analyses for their identification in Fine Arts

10.5194/egusphere-egu21-3142 ◽

2021 ◽

Author(s):

Chiara Anselmi ◽

Antonio Sgamellotti ◽

Manuela Vagnini ◽

Aldo Winkler

Keyword(s):

Magnetic Properties ◽

Magnetic Susceptibility ◽

Magnetic Measurements ◽

Rock Magnetism ◽

Fine Arts ◽

Magnetic Behavior ◽

Spectroscopic Techniques ◽

Magnetic Carriers ◽

Magnetic Techniques ◽

Synthetic Pigments

A multidisciplinary approach, including compositional, spectroscopic and microscopic methodologies, is often used for the analysis and identification of pigments in Fine Arts. Although a large part of widely used natural and synthetic pigments contain Fe-oxides and hydroxides, their magnetic characterization is still poorly explored. The application of rock magnetism analyses through fast, cheap and non-destructive measurements, can be instead useful for the identification and discrimination of pigments through their distinctive magnetic properties.In this preliminary study, the magnetic properties of several iron-based commercial pigments together with paintings models and supports, were analyzed.In order to investigate the compositional differences of pigments by means of their magnetic behavior, the magnetic susceptibility, the hysteresis properties and the magnetic susceptibility variation at low and high temperature were measured on selected samples.All the pigments showed different magnetic properties, mainly related to variable proportions of magnetite, hematite and maghemite as the main magnetic carriers.Further studies will be addressed to define a protocol for applying the magnetic techniques to the characterization of pigments, including tests on samples produced by different brands and different periods, with the final aim of integrating the magnetic measurements with the different spectroscopic techniques commonly employed for the preservation and the analysis of cultural heritage.

Download Full-text